Effects of different protocols of postactivation performance enhancement on the resistance training performance of physically active men

1 Depa men o Physical Educa ion and Spo , Uni e si y o he Basque Coun y UPV/EHU EFFECTS OF DIFFERENT PROTOCOLS OF POST- ACTIVATION PERFORMANCE ENHANCEMENT ON THE RESISTANCE TRAINING PERFORMANCE OF PHYSICALLY ACTIVE MEN P esen ed by A kai z Ga bisu Hualde Vi o ia-Gas eiz, 2023 2 3 Depa men o Physical Educa ion and Spo , Uni e si y o he Basque Coun y UPV/EHU EFFECTS OF DIFFERENT PROTOCOLS OF POST- ACTIVATION PERFORMANCE ENHANCEMENT ON THE RESISTANCE TRAINING PERFORMANCE OF PHYSICALLY ACTIVE MEN P esen ed by A kai z Ga bisu Hualde Supe ised by: Jo dan San os Conceje o Uni e sidad del País Vasco/Euskal He iko Unibe si a ea, UPV/EHU Vi o ia-Gas eiz, 2023 (cc)2023 ARKAITZ GARBISU HUALDE (cc by 4.0) 5 ACKNOWLEDGMENTS I ha e ne e been b illian s udying, bu I ha e ne e s ood no unde s anding why hings happen o how hings wo k. So, when I was augh how o sea ch and il e quali y in o ma ion, I disco e ed a whole wo ld o knowledge a ailable. Fu he mo e, when I was p oposed o do a hesis, I was exci ed. The e y idea ha I could con ibu e o he knowledge people looks o all a ound he globe was inc edible. I also had o become amilia wi h he o he side o esea ching, ejec ion. I was ough a he beginning bu cla i ying. One o he mos impo an hings I ha e lea ned du ing hese yea s is ha no ma e how con inced you a e abou some hing, you can s ill be comple ely w ong. These ou yea s ha e been insane, bu I ha e been su ounded by my amily and iends, and I would like o dedica e hem some lines be o e I s a my disse a ion. My mom, Idoia Hualde, augh me ha pa ience and being cold-minded a e wo o he g ea es i ues a pe son can ha e. Thank you o eaching me ha no e en he g ea es bo anis can g ow a ee in h ee days. My dad, Mikel Ga bisu, augh me he impo ance o seeking pe ec ion h ough discipline and p o essionali y. Thank you o eaching me ha jus because pe ec ion is impossible, i doesn´ mean we shouldn´ look o i . My b o he , Oie Ga bisu, augh me ha s aying ocused on some hing is c ucial when ough imes a i e. Thank you o eminding me why I always walked behind you when we used o go ekking and climbing. 6 My g andmo he , Sa a I ua e, who has los he mos du ing hese yea s. E en i li e s oke you ha d, you ha e always been lo ely and suppo i e. Thank you o you uncondi ional suppo , e en when you did no unde s and wha was going on. My uncle D . Ja ie O dóñez and my aun Na alia Pe ez-Galdós ha e ne e discou aged me om lea ning and s udying, e en when his las yea I called hem o ask abou a comple ely insane idea. Thank you o eaching me ha educa ion is no some hing you can inish. My good iend and w i e Ike Sampe eminded me he impo ance o aking hings easy. Thank you o eaching me ha we li e in an o e ly accele a ed cul u e whe e p oduc i i y elies mo e on doing some hing as han doing he igh hing in ime. My gi l iend, Lau a Gu ie ez, who has been wi h me e e y day since I s a ed his jou ney, who has made me laugh when I mos needed i and who has o ced me o es when I didn´ wan o. Thank you o eaching me ha no one can pass o e a des oyed b idge. Finally, my supe iso D . Jo dan San os Conceje o, i i was no o you, I would ha e d opped ou o college du ing he 3 d yea . Thank you o eaching me ha being a scien is is an a i ude, no a job. 7 We´ e a anged a global ci iliza ion in which mos c ucial elemen s p o oundly depend on science and echnology. We ha e also a anged hings so ha almos no one unde s ands science and echnology. This is a p esc ip ion o disas e . We migh ge away wi h i o a while, bu soone o la e his combus ible mix u e o igno ance and powe is going o blow up in ou aces. Ca l Sagan – The demon-haun ed wo ld: science as a candle in he da k 8 9 SCIENTIFIC CONTRIBUTIONS Pee - e iewed publica ions S udy 1: Ga bisu-Hualde, A., & San os-Conceje o, J. (2021). Pos -Ac i a ion Po en ia ion in S eng h T aining: A Sys ema ic Re iew o he Scien i ic Li e a u e. Jou nal o Human Kine ics, 78(1), 141-150. Quali y indica o s: ISI-JCR Impac ac o : 2.923. 42/87 (Q2) SPORT SCIENCES 2021 S udy 2: Ga bisu-Hualde, A., Gu ie ez, L., Fe nández-Peña, E., & San os-Conceje o, J. (2023). In e mi en Volun a y Isome ic Con ac ions E ec s on Pe o mance Enhancemen and S icking Region Kinema ics in he Bench P ess. Jou nal o Human Kine ics, 87(1), 105- 117. Quali y indica o s: ISI-JCR Impac ac o : 2.923. 42/88 (Q2) SPORT SCIENCES 2022 S udy 3: Ga bisu-Hualde, A., Gu ie ez, L., & San os-Conceje o, J. (2023). Pos -Ac i a ion Pe o mance Enhancemen as a s a egy o imp o e bench p ess pe o mance o oli ional ailu e. Jou nal o Human Kine ics, 88(1), epub ahead o p in . Quali y indica o s: ISI-JCR Impac ac o : 2.923. 42/88 (Q2) SPORT SCIENCES 2022 10 Cong ess communica ions O al p esen a ion: E ec os de las con acciones isomé icas olun a ias in e mi en es en el endimien o y la cinemá ica de la egión de es ancamien o en el p ess de banca X Jo nadas In e nacionales de la Sociedad Española de Medicina del Depo e (Badajoz, Spain); F om 25/11/2022 o 26/11/2022 O he s Ex e nal e iewe o a s udy on he opic o he Resea ch Qua e ly o Exe cise and Spo Ex e nal e iewe o a s udy on he opic o he Jou nal o Human Kine ics 17 RESUMEN El en enamien o de ue za ha ganado una no able popula idad en los úl imos años. Es e c ecien e in e és po los depo es elacionados con la ue za, como el powe li ing, la hal e o ilia o el cul u ismo, ha aumen ado el núme o de compe ido es y en enado es. Dado que la unción p incipal de los en enado es es mejo a el endimien o de sus a le as, se han es udiado a ias es a egias, como la mejo a del endimien o pos -ac i ación (PAPE). La PAPE se ha u ilizado comúnmen e como una es a egia pa a mejo a la p oducción de ue za olun a ia de mane a aguda. No deben con undi se los é minos PAPE y po enciación pos -ac i ación (PAP), ya que exis en cie as di e encias: (i) la necesidad de una con i mación inducida eléc icamen e en el caso de PAP y (ii) el pe il de iempo-po enciación. En es e sen ido, la PAP iene una ida más co a (~4-5 minu os), mien as que la PAPE puede du a has a 20 minu os. La PAPE ha ganado una no o ia popula idad en depo es que se basan en la po encia debido a su capacidad pa a mejo a la asa de desa ollo de ue za de mane a aguda median e p o ocolos que siguen di e en es es a egias. En e esas es a egias, podemos encon a p o ocolos con ca gas muy a iadas, como ca gas óp imas pa a la po encia (op imal powe load), ca gas medias e incluso p o ocolos basados en con acciones pliomé icas. Es os p o ocolos de PAPE son especialmen e ú iles cuando se a a de mejo a el endimien o en a eas depo i as de ca ga submáxima, como pueden se el sp in , el sal o o los lanzamien os. O o ac o impo an e que ienen en cuen a los en enado es es la egión de es ancamien o. Es e é mino hace e e encia a la egión del le an amien o donde se puede alla du an e el en enamien o o la compe ición. Se de ine como la egión en e el p ime pico máximo de elocidad y el pico mínimo de elocidad du an e la ase ascenden e de 18 un le an amien o. La causa del enómeno pa ece se una des en aja mecánica del g upo muscula más débil in oluc ado. Es a egión es al amen e indi idual ya que depende de la can idad de masa muscula del pa icipan e y cómo es á dis ibuida, el g ado de expe iencia del indi iduo en el pa ón mo o que se es ea y la o ma a icula y longi ud ósea del pa icipan e. Se han adop ado di e en es es a egias pa a comba i la egión de es ancamien o, que podemos clasi ica en es a egias a la go plazo (como el en enamien o especí ico) o a co o plazo (donde la PAPE pod ía se ú il). Po an o, los p opósi os p incipales de es a esis ue on: (i) obse a si una es a egia pa a mejo a el endimien o de o ma aguda (es deci , PAPE) es e ec i a sob e la cinemá ica y las ca ac e ís icas de la egión de es ancamien o, (ii) compa a di e en es p o ocolos de PAPE basados en di e en es egímenes de con acción y (iii) es udia si un p o ocolo de PAPE puede mejo a el olumen de en enamien o de ue za. La esis comienza con una e isión sis emá ica de la li e a u a cien í ica, cuyo obje i o es de e mina la combinación ideal pa a un p o ocolo de Po enciación Pos -Ac i ación ca a a mejo a el endimien o. Realizamos una búsqueda bibliog á ica en oc ub e de 2020 (PubMed y Scopus) de a ículos de in es igación o iginales. Después de analiza 202 esul ados, solo se incluye on los es udios que cumplie on con los siguien es c i e ios de inclusión: a) la edad de los suje os e a en e 18 y 30 años; b) los es udios analiza on le an ado es expe imen ados; c) la Po enciación Pos -Ac i ación se es udió en depo es con al os equisi os de la asa de desa ollo de la ue za; d) el p o ocolo de po enciación se ealizó con eje cicios con ba a; e) la e aluación p e ia y pos e io se ealizó con un eje cicio de ue za, sal o e ical o simila (es deci , un squa jump, sal o en con amo imien o o d op jump). Solo se selecciona on es udios e isados po pa es 19 esc i os en inglés. Diecisie e es udios cumplie on con los c i e ios de inclusión, diez enían un ni el de e idencia 1b (ensayos con olados alea o ios de buena calidad) y los 7 es an es enían un ni el de e idencia 2b según la escala de ni el de e idencia de Ox o d. De acue do con los esul ados, incluso si se pueden usa di e en es p o ocolos pa a log a la PAP, pa ece que las in ensidades más al as inducen una mayo mejo a del endimien o. Más p ecisamen e, pa ecía que (i) los le an ado es expe imen ados se bene ician más que sus compañe os sin expe iencia, (ii) las in ensidades al as b indan mejo es esul ados, y (iii) los in e alos de descanso de 7-8 minu os pa ecen ap opiados. Basándonos en esos esul ados, in en amos compa a un p o ocolo de PAPE basado en un égimen de con acción di e en e con un p o ocolo de PAPE adicional de al a in ensidad. El es udio u o como obje i o analiza el papel de un p o ocolo de PAPE de con acción isomé ica máxima en el endimien o y sus e ec os en la cinemá ica de la egión de es ancamien o en compa ación con un p o ocolo de PAPE adicional. Pa a ello, se eclu a on ein iuna pe sonas (edad 26.4 ± 5.4 años) que ealiza on dos sesiones expe imen ales: una consis ía en ealiza una se ie de una única epe ición en p ess de banca plano con el 93% del 1RM (conside ado un p o ocolo adicional pa a induci PAPE) y o a sesión que consis ía en ealiza 15 con acciones isomé icas olun a ias máximas en la egión de es ancamien o de 1 segundo de du ación, con 1 segundo de descanso en e con acciones. Los da os analizados incluían la elocidad de p opulsión media de la egión p e-es ancamien o, el p ime pico máximo de elocidad y el p ime pico mínimo de elocidad. Solo el p o ocolo isomé ico de PAPE mejo ó el endimien o en la egión de p e-es ancamien o ( elocidad media desde el inicio del le an amien o has a el p ime pico máximo de elocidad) (p < 0.001; ES = 0.67, e ec o mode ado), elocidad en el p ime pico máximo (p = 0.005; ES = 0.71, e ec o mode ado) y en el 20 p ime pico mínimo (p = 0.025; ES = 0.38, e ec o pequeño). Los hallazgos de es e es udio sugie en que un p o ocolo de PAPE isomé ico de al a in ensidad mejo a la cinemá ica de la egión de es ancamien o y de la egión p e ia al es ancamien o, lo que ayuda al le an ado a supe a el le an amien o. Es a mejo a es especialmen e e iden e en el p ime pe iodo de la subida, p e io a la egión de es ancamien o, mejo ando el p ime pico máximo de elocidad después del p o ocolo isomé ico. Es o iene como esul ado la ob ención de mayo impulso, acili ando así el paso po la egión de es ancamien o y cambiando el pe il elocidad- iempo. Como los p o ocolos de PAPE suelen usa se en a eas con ca ga submáxima o a eas explosi as, a amos de p oba si un p o ocolo de PAPE es ú il cuando se a a de mejo a el olumen de en enamien o. Es e úl imo es udio u o como obje i o analiza la in luencia de un p o ocolo de PAPE en el endimien o de p ess de banca en una se ie de en enamien o al allo muscula en indi iduos en enados en compa ación con un g upo con ol sin p o ocolo de PAPE. Reclu amos ca o ce pa icipan es con al menos 2 años de expe iencia en en enamien o de ue za (edad 24.57 ± 2.7 años; masa co po al 77.47 ± 12.2 kg; al u a 174.21 ± 7.4 cm 1 epe ición máxima en p ess de banca con aga e medio (1RM): 101.6 ± 25.8 kg), de los cuales 14 comple a on el p o ocolo de con ol y 12 el expe imen al. En el g upo que ealizó un p o ocolo de PAPE, los pa icipan es ealiza on más epe iciones que en la condición con ol (p=0.008; ES=0.5, e ec o pequeño), su úl ima epe ición ue más len a (p=0.02; ES=0.52, e ec o pequeño) y u ie on una mayo pé dida de elocidad (p=0.004; ES=0.75, e ec o mode ado). Los esul ados de es e es udio sugie en que ealiza un p o ocolo de PAPE adicional an es de una se ie al allo pod ía hace que el a le a sea más esis en e a la a iga en a eas de la ga du ación, lo que pod ía esul a en una po encial o ma de mejo a el olumen de en enamien o. La 21 can idad de abajo ealizado po sesión, en endido como núme o de se ies o como onelaje (se ies x epe iciones x kilog amos) es á elacionado con la can idad de masa muscula ganada. Po lo an o, si la PAPE mejo a el núme o de epe iciones has a el allo concén ico, el onelaje po sesión aumen a ía, y lo mismo pod ía ocu i con la hipe o ia muscula . Puede asumi se que esa hipo é ica mejo a en la hipe o ia muscula se debe a una ensión mecánica mayo en la úl ima epe ición y al mayo núme o de epe iciones ealizadas. Sin emba go, el es udio se ealizó con una sola se ie, pe o no se p obó el e ec o de es a se ie y su a iga en pos e io es se ies. La p incipal conclusión de es a esis ue que exis e un dis anciamien o en e la ciencia y la p ác ica, ya que los p o ocolos que se u ilizan habi ualmen e no son e ec i os en los con ex os comúnmen e usados (es deci , sesiones de ue za máxima o compe iciones de powe li ing). Los p o ocolos al e na i os (como los p o ocolos isomé icos) son más adecuados pa a esas si uaciones, ya que las lige as mejo as en la cinemá ica de la egión de es ancamien o pueden se c uciales cuando se iene éxi o en un in en o de 1RM. En cuan o a los p o ocolos de PAPE adicionales de al a in ensidad, deben usa se p incipalmen e en a eas de ca ga submáxima, donde combinados con un in e alo de descanso adecuado pueden b inda cla os bene icios. Palab as cla e: Po enciación Pos -Ac i ación; mejo a del endimien o pos -ac i ación; Región de es ancamien o; powe li ing; AMRAP; allo muscula ; en enamien o de ue za; olumen de en enamien o; ue za isomé ica 22 23 LIST OF SYMBOLS AND ABBREVIATIONS PAPE: Pos -Ac i a ion Pe o mance Enhancemen ATP: Adenosine T iphospha e PAP: Pos -Ac i a ion Po en ia ion CA: Condi ioning Ac i i y 1RM: 1 Repe i ion Maximum ROM: Range o Mo ion min: minu es Ca2+: Calcium ions MLCK: Myosin Ligh Chain Kinase S1: Sub agmen 1 S2: Sub agmen 2 mM: millimola KCl: Po assium chlo ide CAD: Ca aly ic Domain CD: Con e e Domain LD: Le e Domain nm: nanome e! A1: Low ene gy s a e A2: High ene gy s a e " G: Basic ee ene gy change " H: Change in en halpy T " S: T s ands o empe a u e; " S s ands o en opy change MVC: Maximal Volun a y Con ac ion SERCA: Sa co/Endoplasmic Re iculum Ca2+-ATPase 24 # : Pi " P: P essu e change 4: Radius o he ou h powe η: Viscosi y l: leng h F: Blood low F hickness: Comp essi e o ce upon he muscle F adial: Fo ce in he adial di ec ion caused by F hickness CMJ: Coun e Mo emen jump CPX: Complex CPX – CNT: Con as complex CPX – DT: Descending complex CPX – AT: Ascending complex CPX – FCNT: F ench complex RFD: Ra e o Fo ce De elopmen Vs.: Ve sus PPA: Po enciación-Pos Ac i ación PED o: Physio he apy E idence Da abase scale RCT: Randomised Con olled T ials BPM: Bea s Pe Minu e RPE: Ra e o Pe cei ed Exe ion Vmax: Maximum eloci y Vmin: Minimum eloci y Vmax peak: Maximum peak eloci y Vmin peak: Minimum peak eloci y 25 ISO: Isome ic condi ioning p o ocol TRAD: T adi ional condi ioning p o ocol MVIC: Maximal Volun a y Isome ic Con ac ion ANOVA: Analysis o Va iance ES: E ec Size CI: Con idence In e al s 2: a iance o he esponse a iable 1- b : s a is ical powe a : alpha le el CON: Con ol condi ion SD: S anda d de ia ion η2: E a-squa ed, used in s a is ics as an index o he p opo ion o a iance RPD: Ra e o Powe De elopmen p: Signi icance le el. S a is ical measu e used o alida e a hypo hesis. EMG: Elec omyog aphy F: Fo ce m: Mass a: accele a ion Vmax1: Fi s maximum peak in eloci y m·s-1: me e pe second 26 33 4.1.3 Cha ac e is ics o he Pa icipan s ............................................................................................ 97 4.1.4 S udies ma ching olume load .................................................................................................. 99 4.1.5 S udies no ma ching olume load ......................................................................................... 101 4.2 Publica ion 2: In e mi en Volun a y Isome ic Con ac ions E ec s on Pe o mance Enhancemen and S icking Region Kinema ics in he Bench P ess ............................... 104 4.2.1 Kinema ics o he s icking egion ........................................................................................... 104 4.2.2 Mean eloci y changes and RPE ............................................................................................ 107 4.3 Publica ion 3: Pos -Ac i a ion Pe o mance Enhancemen as a s a egy o imp o e bench p ess pe o mance o oli ional ailu e .................................................................. 109 5. DISCUSSION .......................................................................................................... 113 5.1 Publica ion 1: Pos -ac i a ion po en ia ion in s eng h aining: A sys ema ic e iew o he scien i ic li e a u e .................................................................................................... 113 5.2 Publica ion 2: In e mi en Volun a y Isome ic Con ac ions E ec s on Pe o mance Enhancemen and S icking Region Kinema ics in he Bench P ess ............................... 115 5.3 Publica ion 3: Pos -Ac i a ion Pe o mance Enhancemen as a s a egy o imp o e bench p ess pe o mance o oli ional ailu e .................................................................. 119 5.4 Gene al Discussion ........................................................................................................ 121 5.4.1 Gene al concep s .................................................................................................................... 121 5.4.2 PAPE p o ocols o hea y li ing ........................................................................................... 126 5.4.3 Isome ic PAPE and hea y li ing .......................................................................................... 129 6. LIMITATIONS & FUTURE RESEARCH ............................................................ 137 6.1 Limi a ions ..................................................................................................................... 137 6.2 Fu u e esea ch ............................................................................................................. 137 7. CONCLUSIONS ...................................................................................................... 141 7.1 Conclusions .................................................................................................................... 141 34 7.2 Conclusiones .................................................................................................................. 143 8. REFERENCES ........................................................................................................ 149 9. ADDENDUMS ......................................................................................................... 163 35 1 INTRODUCTION E´e o a u h ha ha h a alsehood´s ace Ough one o close his lips as bes as he can, Fo , hough one aul less be, i b ings him shame Dan e Alighie i – In e no XVI (124-126) 36 37 1. INTRODUCTION 1.1 Gene al In oduc ion o he Topic This hesis s udies he e ec o a no el and di e en p o ocol o pos -ac i a ion pe o mance enhancemen (PAPE) in he pe o mance and kinema ics o he s icking egion o he bench p ess and he e ec s o he PAPE on aining olume. The 3 published s udies1–3 s a wi h a e iew o he scien i ic li e a u e o es ablish wha is ecommended by expe s and coaches in he ield1. The pu pose o ha p e ious li e a u e sea ch was based on he b oad spec um o a ailable p o ocols and es ime ecommenda ions. The second s udy2 hen examined he e ec i eness o an isome ic PAPE p o ocol in pe o mance based on p e ious li e a u e4,5. As new p o ocols wi h di e en con ac ion egimes ha e been p oposed6 and p e ious li e a u e sugges ed he e ec i eness o isome ic con ac ions as po en ia ion s imuli 4,5, he in en ion o his s udy was o p o e he e icacy o hose isome ic p o ocols in ield condi ions. Thus, a common exe cise was es ed, he ba bell bench p ess7, wi h an isome ic con ac ion p o ocol, 15 maximal olun a y con ac ions o 1 second wi h 1 second es in e spe sed. Sho ly, we disco e ed ha 15 maximal con ac ions in e spe sed wi h 1 second es esul ed in an e ec i e po en ia ion s imulus. Finally, he hi d s udy3 analysed he e ec o a adi ional PAPE p o ocol on a ask o ailu e in he bench p ess, as a possible mechanism o enhance aining olume and maximise muscle mass gains. In his wi hin-subjec s udy, pa icipan s pe o med he con ol and expe imen al condi ions in a andomised o de . In bo h condi ions 38 pa icipan s pe o med a ask o oli ional ailu e wi h he 80% o hei 1RM in he bench p ess, bu in he expe imen al condi ion hey pe o med a adi ional PAPE p o ocol p io o he ask o ailu e. Resul s indica e ha PAPE could be a use ul ool o imp o e pe o mance in submaximal in ensi y asks, imp o ing pe o med olume. Bu , be o e s a ing in o much o wha is desc ibed abo e, some impo an and ecu en e ms a e de ined in he ollowing sec ion. 1.2 Backg ound and De ini ions Resis ance aining has gained popula i y o e he yea s as i s bene i s 8–10 and muscle issue´s bene i s11–13 o heal h ha e been unmasked. Also, he popula i y o s eng h compe i ions (such as s ongman, weigh li ing, and powe li ing compe i ions) and physique shows (such as bodybuilding) ha e inc eased exponen ially. In an eage ness o apid muscle mass gain, some basic concep s o esis ance aining a e de alua ed, such as he impo ance o a p ope wa m-up. Wa ming up p epa es he whole sys em o wha is coming du ing he aining session aising body empe a u e (inc easing Adenosine T iphospha e -ATP- u no e , muscle ib e unc ionali y, c oss-b idge cycling, and conduc ion eloci y) and hus, being able o achie e he bes pe o mance possible14. The e a e plen y o p o ocols a ailable, such as passi e body empe a u e aises, plyome ics, low olume, and hea y esis ance aining bou s, mobili y d ills, pos - ac i a ion po en ia ion and so on14. B ie ly said, wa ming up p epa es he body o he s ess bou ha aining supposes. Once he wa m-up is pe o med, we a e eady o ain. I is known ha in o de o adap , we mus pu ou bodies unde a con olled amoun o s ess15–17, which has been 39 pos ula ed bo h in he gene al adap a ion synd ome 15 and in he subsequen i ness- a igue model17. To s anda dise aining bou s and a igue managemen , and consequen ly he applied s ess, se e al quan i ica ion me hods ha e been p oposed. One o hose me hods is he measu emen o he mean p opulsi e eloci y (in m·s-1) and he eloci y loss (exp essed in m·s-1 o by a pe cen age) o he li 18. When a se is pe o med eally close o muscle ailu e, he eloci y- ime ela ionship o he li changes, and a zone known as s icking egion appea s19,20. I is well known ha aining o ailu e leads o g ea e s ess han no aining o ailu e21. Ne e heless, whene e he objec i e is o imp o e pe o mance pe se o o imp o e pe o mance o gain muscle mass, aining nea o muscle ailu e is needed o op imise gains22,23 , bu should be wisely pe iodised21,24. The close o ailu e, he highe he p oduced a igue 25,26. As highe olumes seem o b ing mo e gains27,28 , i seems in elligen app oaching ailu e bu ying no o de imen he o al amoun o olume ha we a e capable o ole a e. In his way, esis ance aining should be execu ed always unde he supe ision o a p o essional, o a leas , ollowing some good, e idence-based, and s uc u ed guidelines. As e idence seems solid agains aining sys ema ically o ailu e, whe he you a e an expe imen ed o no ice li e , i seems easonable o op imise he wa ming up s a egy o a oid ailu e du ing li ing. As men ioned ea lie , se e al s a egies a e a ailable, bu his hesis ocuses on he e ec s o he pos -ac i a ion pe o mance enhancemen on he s icking egion kinema ics. 40 1.2.1. Pos -Ac i a ion Po en ia ion o Pos -Ac i a ion Pe o mance Enhancemen ? 1.2.1.1 B ie de ini ion Bo h Pos -Ac i a ion Po en ia ion (PAP) and PAPE e e o an imp o ed con ac ile capaci y o a muscle a e an in ense bou o exe cise, known as condi ioning ac i i y (CA). This is, a e an in ense bou o exe cise he muscle issue has an imp o ed capaci y o exe o ce olun a ily o a gi en s imulus o agains a gi en esis ance. The main di e ence be ween PAP and PAPE is ha o con i m he p esence o he i s one, elec ic s imula ion is used, while he e m PAPE is used when con i ma ion ia elec ic s imula ion is no ca ied ou 29 . The condi ioning ac i i y mus accomplish some equi emen s o p oduce an imp o emen in pe o mance: a) The e mus be a biomechanical simila i y be ween condi ioning ac i i y and he es ed mo emen 1 b) A minimum in ensi y is needed, achie ed using ei he high-load and low- eloci y exe cises o ligh -load and high- eloci y exe cises30. When high-load and low- eloci y p o ocols a e used, excessi e p oximi y o muscle ailu e mus be a oided, as high a igue is p oduced21,24. c) Reco e y be ween condi ioning ac i i y and he es ed mo emen is o u mos impo ance. In his way, s onge indi iduals can bene i om sho e es in e als (5-7 mins) han non- ained o weake indi iduals (>8 mins)31. In addi ion, i seems ha sel -selec ed es in e als adjus well o each one´s needs32. 41 The mechanisms behind PAPE a e no ully elucida ed. In he beginning, he phospho yla ion o he egula o y ligh chain o myosin was p oposed as he unde lying mechanism (as in he case o PAP), bu disc epancies in he occu ing ime we e ound. This led o he c ea ion o new e ms and he p oposal o new mechanisms. 1.2.1.2. His o y o Pos -Ac i a ion Po en ia ion Fi s in es iga ions alking abou a opic ela ed o pos -ac i a ion po en ia ion (PAP) go back o he ea ly XX cen u y, whe e Lee33 s udied in mo e de ail wha desc ibed Bowdi ch in 1867. In his s udy, Lee desc ibed wha he eppe was, o , in English, he s ai case po en ia ion. This s ai case po en ia ion is based on he achie emen o be e muscle con ac ion a e he applica ion o epea ed low- equency s imula ions as condi ioning ac i i y o s imulus. La e in ha cen u y, in 1937, he e m pos - e anic po en ia ion34 was bo n, which e e s o an obse ed augmen a ion o he ension p oduced by a ib e a e e anic con ac ion. Finally, in 1976 Bu ke e al. (1976)35 in oduced he e m pos -ac i a ion po en ia ion (PAP), whe e hey used equencies and numbe o pulses mo e simila o wha ou body can achie e physiologically. This es ablished a well-ma ked di e ence be ween pos - e anic po en ia ion and PAP. Nowadays, is commonly accep ed ha PAP is con i med when an ampli ude in wi ch con ac ion is measu ed (a wi ch is he con ac ile esponse o a single elec ical s imulus applied di ec ly o he muscle o he mo o ne e). Thus, PAP needs o elec ically e oked e i ica ion, bu his seldom happens. This is one o he easons why he e m Pos - Ac i a ion Pe o mance Enhancemen (PAPE) was p oposed, which e e s o a pe o mance enhancemen p oduced by a olun a y ac ion (like PAP), bu wi h no wi ch 42 e i ica ion29 . This p oblema ic will be u he discussed in “ he con using axonomy p oblem” sec ion. 1.2.1.3 The di e si y o PAPE p o ocols Nume ous PAPE p o ocols ha e seen he ligh o e he las yea s wi h he in en ion o imp o ing acu e pe o mance in esis ance aining. The mos common p o ocol ha can be seen in almos e e y gym is a high-in ensi y and low- eloci y p o ocol, whe e a nea maximal li is pe o med. Fo his ype o p o ocols, a hea y se o one epe i ion is pe o med be o e he e ec i e wo k o he aining session i sel , looking o imp o ed pe o mance in ha exe cise. This “hea y se ” is usually pe o med be ween 93-100% o he one epe i ion maximum (1RM), and equen ly, his epe i ion eaches ailu e and elies on he help ha a spo e ( he pe son aking ca e o he pa icipan no ge ing hu du ing he aining session) gi es o ha ainee. This usual p o ocol o PAPE eminds us he “ o ced epe i ions” ad anced aining me hod o hype ophy36, which elies on eaching ailu e and ge ing help o pe o m some mo e epe i ions. While he o ced epe i ions me hod could be in e es ing o achie e muscle hype ophy when p esc ibed wisely, hey a e no o achie e PAPE, as acu e a igue is mo e han needed and could unde pin he bene i s. Anyway, he use o his p o ocol is de i ed om a misin e p e a ion o scien i ic wo k behind. When applied co ec ly, his high-in ensi y and low- eloci y p o ocol should be ela i ely nea o, bu no each ailu e1. This is based on he i ness- a igue model17, which usually is applied in he long e m, bu no hing seems o sugges ha i canno be used o sho - e m o acu e adap a ions as PAPE. Acco ding o his model, he highe he applied 49 I. Two o mo e condi ions mus be compa ed II. Subjec s mus ha e ma ked expe ience in he pe o med ask. I hey do no ha e expe ience, amilia isa ion is c ucial, as he lea ning e ec could lead o misin e p e a ions o esul s. III. Condi ioning p o ocols should be applied in andom o de IV. I possible, a double-blind app oach should be conside ed. As he esea che canno be blinded, i is impo an ha subjec s do no know wha p o ocol hey a e going o un, and is o u e mos impo ance ha hey do no know wha esea che s expec o he p o ocol, as esul s could be biased Is wo h men ioning ha MacIn osh e al. (2012)29 highligh he impo ance o moni o ing body empe a u e whene e possible o be able o dis inguish e ec s caused by PAP/PAPE o by he empe a u e aise i sel 14,70. Blaze ich and Babaul 59 men ion some possible mechanisms o explain PAPE´s ime cou se, such as inc eased wa e low in o he muscle cell, which could lead o imp o ed Ca2+ sensi i i y, which ul ima ely leads o an augmen o a e o o ce de elopmen . As a ma e o ac , Sugi e al. (2013)71 s a ed ha in condi ions o low ionic s eng h (low concen a ion o ions in a solu ion), muscle ib es could exe highe o ces han compa ed o hose condi ions o highe ionic s eng h (50mM and 170mM KCl espec i ely), e en i maximum unloaded sho ening eloci y emained unchanged. They a ibu ed he imp o emen o o ce o an ampli ica ion o he o ce exe ed by e e y myosin head (inc easing wo old) a he han o he quan i y o o med c ossed b idges. In a la e s udy by he same g oup72 an elec on mic oscope combined wi h an en i onmen al gas chambe was used o assess mo e accu a ely myosin´s powe s oke mobili y. Sho ly, he 50 myosin head can be di ided in o he ollowing pa s: (i) The ca aly ic domain (CAD) ha has a p oximal ( espec o he myosin backbone) and a dis al pa , (ii) he con e e domain (CD) and (iii) he le e domain (LD), which is bound o he Sub agmen 2 (S2) o he myosin (Figu e 1). Figu e 1. Rep esen a ion o he myosin head and i s pa s. CAD: Ca aly ic domain; 1: Binding si e o an ibody 1, CAD dis al pa espec o he myosin backbone; 2: Binding si e o an ibody 2, CAD p oximal pa espec o he myosin backbone; CD: Con e e domain; LD: Le e domain; S2: myosin sub agmen 2. Adap ed om Sugi e al. (2015)72 In his s udy72, esea che s showed ha unde no mal condi ions, he dis al po ion o CAD pe o med a powe s oke o 3.3 ± 0.2 nm (n = 732) and he p oximal egion o CAD 2.5 ± 0.1 nm (n = 613), while in low ionic s eng h condi ion, he dis al po ion o CAD pe o med a powe s oke o 4.4 ± 0.1 nm (n = 361) and he p oximal po ion 4.3 ± 0.2 nm (n = 305). This inc emen in he pe o med powe s oke is in line wi h he hypo hesis ha in low ionic s eng h condi ions he imp o ed o ce is due o he 51 augmen a ion o o ce pe myosin head a he han o he numbe o c oss-b idges o med. Ne e heless, he acc e ion o wa e con en inside muscle cells (also known as cell swelling) is p oduced a e an in ense bou o esis ance aining23 o by augmen ed blood pe usion, so u he esea ch is needed o know i he minimal cell swelling ha a wa m- up p oduces could be e ec i e o imp o e he o ce exe ed by each myosin head. Ano he p omising mechanism o explain he elusi e mechanism behind PAPE is muscle empe a u e. Decos e e al. (2005)73 s udied he e ec o di e en empe a u es o e he wo king s oke o ac in-myosin. In his s udy, he wo king s oke was di ided in o ou phases: I. Phase 1 is a change in leng h due o he elas ic componen s o he sa come e II. Phase 2 is he sho ening di ec ly p oduced by he wo king s oke III. Phase 3 is he educ ion o sho ening eloci y due o de achmen and ea achmen o he myosin head along he ac in ilamen IV. Phase 4 Final sho ening a cons an eloci y due o s eady-s a e de achmen /a achmen o myosin heads In hei s udy, Decos e e al. (2005)73 ound ha wi h inc easing empe a u e phases 2 and 4 we e as e , while phase 3 was sho e . Addi ionally, hey ound ha bo h passi e and ac i e elemen s o he sa come e we e s ained in p opo ion o o ce, poin ing o a ise in o ce pe myosin head as he eason why he inc ease in empe a u e p oduces mo e o ce. This augmen ed o ce pe myosin head could be due o a highe quan i y o myosin heads in a high ene gy s a e. Au ho s p opose ha he inc ease in empe a u e p o okes a lowe ing o basic ee ene gy, acili a ing he ansi ion o myosin heads om 52 a low ene gy s a e (A1) o a high ene gy s a e (A2). The lowe ing in basic ee ene gy makes he eac ion happen easie o e en spon aneously (DG = DH - TDS; his esul s in DG > 0), making i easie o myosin heads o achie e he high ene gy s a e. Bu he p incipal limi a ion o his s udy is ha he empe a u es hey use a e e y low (be ween 2ºC – 17ºC), which makes he esul s di icul o ex apola e o physiological condi ions, e en i i shows ha empe a u e could play an impo an ole. In addi ion, he ole o empe a u e in muscle con ac ion was ecen ly add essed by Rod igues e al. (2022)74 in hei e iew. In his s udy a e men ioned wo u he s udies, one by Racinais e al. (2017)75 whe e pa icipan s imp o ed hei maximal olun a y con ac ion (MVC) and ano he s udy by Go o e al. (2011)76 whe e pa icipan s imp o ed hei muscle mass. I would like o highligh some poin s he e. Fi s , in Racinais e al. (2017)75 he e is no desc ip ion o pa icipan s´ expe ience le el in s eng h aining, so possibly hey could be no ices. In Go o e al. (2011)76 pa icipan s do no p ac ice se ious o compe i i e le el spo , only ec ea ionally. Also, in his las s udy, muscle mass is augmen ed, bu muscle mass augmen a ion and imp o emen o unc ional hype ophy a e no he same, as he main objec i e o any esis ance aining plan is o seek an augmen a ion o con ac ile p o ein quan i y52. Finally, is wo h men ioning ha bo h s udies alk abou passi e hea ing p o ocols, which helps us unde s and he po en ial in e es s o s udying empe a u e e ec on pe o mance, bu esul s should be aken ca e ully, as passi e hea ing p o ocols a e long and no applicable in ield condi ions (1h / day o e 11 days75 and 8h /day, 4 days /week o e 10 weeks76 ). Lea ing aside long- e m empe a u e aise´s po en ial bene i s, Rod igues e al. (2022)74 ocus he es o he e iew on he acu e e ec s o empe a u e aises. They de end ha 53 empe a u e aises imp o es hal - elaxa ion ime o he con ac ile appa a us, which would be caused by he imp o ed kinema ics o Ca2+, as sugges ed by he imp o ed ac i i y in he Sa co/Endoplasmic e iculum Ca2+-ATPase (SERCA), ha has as he main unc ion o anspo Ca2+ om cy osol back o he sa coplasmic e iculum61. Wa e and empe a u e seem wo p omising mechanisms o PAPE, bu could hey be ela ed somehow? Could hey be wo sides o he same coin? The e iew by Rod igues e al. (2022)74 ollows exposing ha empe a u e aises can cause blood pe usion by an inc eased libe a ion o adenosine iphospha e (ATP), which ac s as a asodila o . When asodila ion occu s, blood low inc eases ollowing Poiseuille´s law61, which s a es ha : $=#·"'·(! 8·*·+ He e we can see ha i p essu e di e ence ( " P), iscosi y (η), and leng h (l) a e kep cons an , blood low (F) will inc ease p opo ionally o he ou h powe o he adius o he blood essel ( 4). This augmen ed low is due o he lamina low o he blood when he adius inc eases. In small essels, all he blood inside causes ic ion agains he essel´s walls, while inc easing he blood essel´s adius inc eases he amoun o blood ha can ge inside. I mo e blood ge s inside he essel, only he ou e mos laye o blood will cause ic ion agains he blood essel´s wall and he cen e mos laye will ci cula e as e (which is known as lamina low pa abolic eloci y p o ile)61,77,78. 54 This augmen ed blood low due o asodila ion inc eases in amuscula wa e con en , which leads us again o Sugi e al. (2013; 2015)71,72 , bu s ill we do no know why i happens. The answe could be in he s udies by Eng e al. (2018)79 and Eng & Robe s (2018)80. In hei s udies, Eng e al. (2018)79 and Eng & Robe s (2018)80 s a e ha due o he iso olume ic p ope y o he muscle ib e, when i con ac s, i can be de o med in any di ec ion o hogonal o he line o ac ion. When McKibben ac ua o s we e disposed close o each o he o mimic eal muscle ib e condi ions du ing muscle con ac ions, hey saw ha each ac ua o limi ed he upwa ds and downwa ds expansion o he adjacen ac ua o s, p oducing a adial expansion o he sides, and e en o a ions, i needed. One o he mos impo an hings highligh ed in his model is ha hose o ces ha a e no aligned wi h ib es´ line o ac ion ( hose o -axis o ces), load in amuscula connec i e issue and luid. These o -axis o ces a e caused by comp ession o in amuscula luid, equi ing ib es o expand adially as hey sho en. The second cause o he o -axis o ces a e he hickness o ces gene a ed in penna e muscles, he componen o he o ce ha comp esses muscle in he hickness di ec ion. Thus, he e a e wo o ces de o ming muscle ib es: (i) he hickness o ce ha c ushes muscle “ om upside down” and (ii) he adial o ce ha expands he ib e. Au ho s hypo hesise ha o coun e ac he hickness o ce, in amuscula luid expands causing he adial expansion. This adial expansion loads muscula elas ic elemen s such as endomysium, pe imysium, and epimysium (Figu e 2). 55 Figu e 2. Link among empe a u e, wa e con en and o ce ansmission. Filled blue ci cles ep esen wa e molecules; F hickness: Fo ce in he upside-down di ec ion ha c ashes o comp esses he muscle; F adial: Radial expansion p oduced by luid in esponse o F hickness . Adap ed om Rod igues e al. (2022)74 In summa y, in amuscula luid edi ec s he hickness comp essi e o ce o adial s e ching o ce, o which muscles a e p epa ed due o hei elas ic componen s. Conside ing his, inc emen s in in amuscula wa e may enhance muscle comp essi e o ce ole ance, ac ing like a sp ing, and imp o ing o ce ansmission74, which could explain he link be ween wa e and muscle empe a u e in enhanced p oduced o ces. E en i his seems p omising as an explana ion o PAPE, wha di e ence would be be ween a empe a u e aise caused by a classic wa m-up and a empe a u e aise caused by PAPE? Could his empe a u e aise be signi ican ? Weige e al. (2018)81 ound small and non-signi ican empe a u e changes a e 10 epe i ions o biceps cu l a 70% 1RM, sugges ing ha some PAP/PAPE p o ocols ( he adi ional hea y p o ocols consis ing o 1 se o 1 epe i ion o example) a e unlikely o ely on his mechanism. Boullosa e al (2018)82 men ion ha a possible Ca2+ aise due o low- equency wi ches ha could enhance pe o mance in hose p o ocols. This would p oduce an e ec simila o MLCK ac i a ion, bu wi hou myosin phospho yla ion. 56 In any case, exis ing PAP/PAPE p o ocols a e di e se, some could ely in a mechanism and o he s in o he mechanism. Could i be ha PAPE is an ex ension o PAP o e ime? I is easonable o hink ha myosin egula o y ligh chain phospho yla ion occu s and ha i s e ec is leng hened due o empe a u e aises, in acellula wa e con en , imp o ed Ca2+ sensi i i y o ano he mechanism. As scien is s, we end o compa men alise e ec s and i s causes, bu he human body is complex and no hing seems o sugges ha PAP and PAPE happen independen ly one o each o he 59,83. This is, PAP occu s be o e PAPE because o he apid ac ion o MLCK, and PAPE occu s a e o some mechanism no ully elucida ed ye . Bu , e en i PAPE has ano he mechanism behind, his does no mean ha PAP could no con ibu e o PAPE´s e ec s. PAPE could pe ec ly be an ex ension o PAP o e ime by ano he syne gis ic mechanism. 1.2.1.6 The con using axonomy p oblem Conside ing all ha has been said in he p e ious sec ion and emembe ing ha PAP las s ~4-5 min, why a e so many s udies alking abou PAP and epo ing pe o mance imp o emen s 8,10 o e en 20 min a e condi ioning ac i i y? The e a e mo e e ms han PAP, and he uni ica ion o hose e ms seems ha de han he elucida ion o he mechanism behind PAPE. O iginally, PAP and PAPE we e c ea ed wi h he in en ion o simpli ying hings o esea che s: PAP was used o alk abou po en ia ion e i ied wi h elec ic wi ch, and PAPE when ha e i ica ion was no ca ied ou 84 e en i in bo h cases he condi ioning ac i i y elies on a olun a y con ac ion. 57 Howe e , a a ie y o new e ms ha e been p oposed in addi ion o hose wo o iginal e ms. One o he a emp s o es ablish a mo e p ecise e minology was ca ied ou by Boullosa e al. (2020)85. They de end ha a mo e accu a e e minology is needed o include some in luencing ac o s like aining expe ience1, sex di e ences86 and aining backg ound87 . Following his line o easoning, hey p opose he ollowing scheme o name any po en ia ion p o ocol: Pos -(condi ioning ac i i y) ( e i ica ion es ) Po en ia ion in (Popula ion) Some examples o ha scheme a e p o ided in hei pape : • Pos -high in ensi y long in e als, sp in po en ia ion in well- ained unne s • Pos -eccen ic lywheel squa swim s a po en ia ion in a si y ained male swimme s This is a eally comple e p oposal, whe e all de ails a e speci ied in he name o he po en ia ion p o ocol, bu i does no seem eally applicable in eal li e whe e mo e s aigh o wa d names a e easie o emembe . Based on he ex eme complexi y o his p oposal, Smi h and MacIn osh (2021)83 eplied, de ending hei old and simple wo e m axonomy (PAP & PAPE, i espec i e o p o ocols, sex, o popula ion). Recen ly, Co mie e al. (2022)30 ied a new axonomy p oposal. In his case, esea che s summa ise exis ing p o ocols o h ee possible ypes: A. One o se e al se s o high-load exe cise (back qua ) be o e a low-load exe cise (CMJ) 58 B. One o se e al se s o low-load and high- eloci y exe cise (CMJ) be o e a high- load exe cise (squa ) C. Al e na ing high-load and low-load exe cises in a se -by-se ashion They p opose a b oade e minology han PAP and PAPE a he ime ha hey no o iously simpli y he e minology p oposed by Boullosa e al. (2020)85. They s a p oposing “Complex” as an umb ella e m which is going o be combined wi h ou di e en sub- e ms o implemen a ions, namely: I. Con as : An exe cise sequence al e na ing high-load and low-load exe cises in a se -by-se ashion (e.g., Back Squa 85% 1RM – CMJ - Back Squa 85% 1RM – CMJ) II. Ascending: Se e al se s o low-load exe cise be o e a high-load one (e.g., CMJ – CMJ – Back Squa 85% 1RM – Back Squa 85% 1RM) III. Descending: Se e al se s o high-load exe cise be o e a low-load one (e.g., Back Squa 85% 1RM – Back Squa 85% 1RM – CMJ - CMJ) IV. F ench Con as : A hea y compound exe cise – A plyome ic exe cise – Ligh o mode a e compound exe cise – Assis ed plyome ic exe cise Thus, combining he umb ella e m (Complex – CPX) wi h i s ou sub- e ms, depending on he cha ac e is ics o he p o ocol ha is going o be used, he new e minology would be: (i) Con as complex (CPX – CNT), (ii) Descending complex (CPX – DT), (iii) Ascending complex (CPX – AT), o (i ) F ench Con as Complex (CPX – FCNT). This las p oposal seems he mo e sui able one, as i emains concise a he ime i is speci ic. I would like o add ha a new e m should be c ea ed speci ically o eccen ic6 65 1.3 Theo e ical F amewo k o he Thesis 1.3.1 Ideological Basis As a new s eng h coach and Spo Science s uden , I wan ed o lea n as much as possible o apply all ha knowledge in o my wo k. When I s a ed eading and lea ning on my own and ealising how hings wo k, how I could imp o e my aining, I s a ed no icing how people a ound me ain in he gym. O cou se, no e e yone had a coach (ei he online o p esen ial), bu e en some o hose people unde he supe ision o an online coach, used o ain ollowing old guidelines o scien i ically disc edi ed me hods, exe cises o echnical s anda ds. Among hose disc edi ed e ms and echniques, PAPE (wha in gyms is s ill known as PAP) and S icking Region (wha , again, is s ill known as S icking Poin ) we e eally popula . When I ealised abou his si ua ion, in e es ing ques ion came o me: 1. Why do so many coaches use he e m PAP ins ead o PAPE 2. Why do so many powe li ing coaches say S icking Poin , and no Region? 3. Why do coaches use a PAP/PAPE s a egy p io o a hea y se when mos o s udies a e o ien ed o submaximal in ensi y wo k? 4. Why do coaches assume ha be e pe o mance p oduced by PAP/PAPE equals mo e muscle mass gain? 5. Why don´ coaches use mo e han a adi ional PAPE p o ocol? This disconnec ion be ween scien i ic li e a u e and coaches´ p ac ice spa ked he idea o his hesis. Why was his happening? Is science a ailable and unde s andable o g adua ed s uden s and coaches? 66 S eng h aining has gained no o ious popula i y. The quan i y o publica ions, whe he i is o heal h o pe o mance, has aised no ably (437 publica ions indexed in PubMed in 2000 s. 5,886 publica ions indexed in PubMed in 2021). This is no unusual conside ing ha in science, wha is ue oday, can be e u ed omo ow by ano he s udy. Bu a e hose publica ions ead by someone? When s udying he Spo Science deg ee, we a e augh how o look o in o ma ion and how o il e ha in o ma ion, wha in my own opinion, is he mos impo an compe ence acqui ed du ing he 4-yea jou ney. Those who eally enjoy s udying o who eally app ecia e he po en ial sou ce o knowledge hey a e p esen ed when lea ning hese skills, a e la e known as scien is s. Usually, whe he hey unde go a PhD o dedica e hei li e o di ulga ion in pe sonal blogs o social ne wo ks, i does no ma e , hey a e esponsible o c ea ing, in e p e a ing and eaching wha is new and wha needs o be known. Bu wha abou aine s and coaches? Is science he p i ilege o a small popula ion wea ing whi e lab coa s, he s ange language o people ha has ne e ained? Is one on one coaching ese ed o hose people ha a e only based on expe ience, o hose oo soldie s? Nowadays his di ision is happening and is some hing we should hink abou . I scien is s a e making con ibu ions and ad ances in spo science knowledge, bu his knowledge is no being ead by coaches, wha use does i ha e? O cou se, esea ching abou a opic o he me e pu pose o knowing, e en i i does no ha e eal wo ld applica ions is legi , and mus be done, as his can de i e in di e en esea ch lines in he u u e ha will ha e applica ion. 67 1.3.2 F om Theo y o Reali y: When did science and p ac ice ake di e en pa hs? In a s udy based on a ansc ip ion o a ound able o he inaugu al cong ess o he Aus alian Associa ion o Exe cise and Spo s Science by Bishop e al. (2006)105, pa icipan s we e asked abou wha spo -science o hem was, abou he necessi y o ins an applicabili y o esea ch and i he p oblem was due o he lack o communica ion abili ies o he scien is s. Sho ly, he e was a clea di e en ia ion on base spo -science and applied spo -science. The i s was made o publica ion, and he applicabili y in ield was seconda y, while he las one was science made o applica ion in coaching, and i may o may no be published. This di e ence was s ill p esen in he second ques ion, whe e i was s a ed ha he b oad majo i y o coaches asked o apid solu ions, while less coaches we e pa ien enough o wai o longi udinal s udies o se ies o s udies. These wo ques ions s and ou some hing: coaches hink ha s udies should be mo e appliable and sho - e m o ien ed. Bu , as D . Robe New on s a ed du ing ha ound able, impo an esul s canno come ou o nowhe e, hey need ime and a se ies o p eceding s udies; asking only o sho - e m o ien ed s udies does no make sense. Ins ead, coaches need pa ience and abili y o in e p e esul s and seek o applica ion. E en i coaches a e pa ien , i is s ill he doub i he p oblem elies on he lack o in e p e a ion abili y o coaches o poo communica ing abili y o scien is s. As hei name indica e, spo -scien is s esea ch a ound spo , ha is, o imp o e pe o mance, educe inju y isks, imp o e echnologies… Thus, a good communica ion among he 68 p incipal s akeholde s is c ucial, and esea che s need o imp o e hei communica ing abili ies as much as hei esea ch abili ies105. This is why he e a e scien is s ha a e no dedica ed o esea ch, bu o in e p e a ion o esea ch o he less specialised public, as unde g adua e s uden s. This is o pa amoun impo ance, as nowadays social ne wo ks a e used by e e yone o ob ain in o ma ion. Based on www.s a is a.com , Facebook, You ube and Ins ag am a e 3 o he 4 mos used social ne wo ks, wi h 2,910 million, 2,562 million and 1,478 million use s in 2022. E e yone ollows people o subjec s in which a e in e es ed, and he e is whe e scien is s should come in. They should be he e o igh misin o ma ion and misin e p e a ion; hey should be he e o p o ide audience wi h quali y in o ma ion. Science is useless i i eaches nobody. D . Ca l Sagan belie ed ha he e was an u ge o s op conside ing science as an eli is language, ha science needed o be unde s ood by e e yone. D . Richa d Feynman once said ha i you canno explain some hing in simple e ms, you don´ unde s and i . These wo g ea scien is s belie ed in he necessi y o communica ion skills, o make science a ailable o anyone who needed i . O cou se, he e a e scien i ic subjec s and discussions ha canno be simpli ied enough o be unde s ood by people wi hou p e ious s udies, and hose subjec s a e ine i ably ese ed o he scien i ic communi y. Anyways, I s ill hink ha mos o he people pe cei e science as an inaccessible ield. One o he main easons why I decided o do my PhD was p omo ing he “scien i ic coach” igu e. I s ongly belie e ha scien is s can be coaches o ad iso s i hey a e eally in e es ed, and coaches can (and should) be scien is s, as hey need o keep up wi h 69 science o do hei job he bes hey can. The e is no need o publish pape s by coaches i hey do no wan o, bu a leas hey should be able o sea ch, il e and ead scien i ic s udies. I am no p e ending o disdain he impo ance o expe ience when coaching. Expe ience can be c i ical, especially when he spo in ol es di icul echnical o ac ical aspec s. Bu wha is clea is ha he e is a need o a b idge be ween science and p ac ice, and p omo ing gene al public o ien ed di ulga ion could help. Specialised ex s a e needed and ha e hei pu pose; bu as scien is s, we should no o ge ha science, e en i made by a small, specialised popula ion, is mean o e e yone, and should be as accessible as possible. Thus, he s a ing poin o his hesis was o y o emo e as many biases as possible, as many misin e p e a ions as possible, and c ea ing a documen o which any s eng h, powe li ing o bodybuilding coach hinking o implemen PAPE in hei a hle es´ aining could go o. I ha e ied sepa a ing me e cu iosi y and non-applicable con en (as physiological mechanisms) om he mo e applicable and ield o ien ed (as di e en exis ing p o ocols and hei possible uses), wi h he in en ion o easing he eading and acili a e inding wha he eade is looking o . 70 71 2 HYPOTHESES & AIMS The cul u e we ha e does no make people eel good abou hemsel es. And you ha e o be s ong enough o say i he cul u e doesn´ wo k, don´ buy i . Mi ch Albom – Tuesdays wi h Mo ie 72 73 2. HYPOTHESES & AIMS 2.1. Hypo hesis In o de o make his case 3 pape s we e planned. The i s s udy was a sys ema ic e iew o he scien i ic li e a u e a ailable on PAP and PAPE o s eng h spo s, and i was pe o med o se e as an in oduc ion. Following his we analysed he possible e ec o an isome ic PAPE p o ocol compa ed o a adi ional PAPE p o ocol in high-loaded (85% 1RM) s eng h aining, and i s e ec s on s icking egion kinema ics. Finally, we analysed he e ec s o a high-loaded (93% 1RM) adi ional PAPE p o ocol compa ed o a con ol g oup (no PAPE) on pe o med epe i ions un il oli ional ailu e in a se o bench p ess, as a po en ial way o imp o e muscle mass adap a ions. In essence, we analysed he possible applica ion o a di e en con ac ion egime PAPE p o ocol, o inc ease he numbe o a ailable use ul p o ocols and he e ec o a PAPE p o ocol in aining olume. This was pe o med wi h he in en ion o expanding he numbe o a ailable ools o coaches and s eng h aining specialis s. 2.2. Summa y o Aims • Examine he li e a u e ega ding Pos -Ac i a ion Po en ia ion and Pos -Ac i a ion Pe o mance Enhancemen (Publica ion 1) • Examine he impo ance o olume and in ensi y in Pos -Ac i a ion Po en ia ion and Pos -Ac i a ion Pe o mance Enhancemen (Publica ion 1) • Examine he e ec s o an isome ic PAPE p o ocol compa ed o a adi ional PAPE p o ocol (Publica ion 2) 74 • Examine he e ec s o an isome ic and adi ional p o ocol o e he s icking egion (Publica ion 2) • Compa e he pe o med olume in a aining bou wi h and wi hou a high-loaded adi ional PAPE p o ocol (Publica ion 3) • Compa e he eloci y loss du ing a aining bou o oli ional ailu e wi h and wi hou a high-loaded adi ional PAPE p o ocol (Publica ion 3) • Explo e why any po en ial disc epancies occu ed (All Publica ions) 81 3. METHODOLOGY 3.1 Publica ion 1: Pos -ac i a ion po en ia ion in s eng h aining: A sys ema ic e iew o he scien i ic li e a u e 3.1.1 Expe imen al App oach o he P oblem A li e a u e sea ch was conduc ed on Oc obe 23, 2020. The ollowing da abases we e sea ched: PubMed and Scopus. The p e iously named da abases we e sea ched om incep ion o Oc obe 2020, wi h language limi a ions: only pee e iewed a icles in English we e selec ed. Ci a ions om scien i ic con e ences we e excluded. 3.1.2 Li e a u e Sea ch In he da abase, he i le and abs ac s we e sea ched. The ollowing MeSH e ms and key wo ds, combined wi h he Boolean ope a o s (AND, OR), we e used: “a hle ic pe o mance”, “ esis ance aining”, “pos ac i a ion po en ia ion”, “PPA”, “PAP”, “pos - ac i a ion po en ia ion”, “po en ia ion pos ac i a ion”, “po en ia ion pos -ac i a ion”, “pe o mance”, “s eng h pe o mance”, “s eng h aining”, “s eng h” and “powe li ing”. No addi ional il e s o sea ch limi a ions we e used. 3.1.3 Inclusion C i e ia S udies we e eligible o u he analysis i he ollowing inclusion c i e ia we e me ; a) subjec s´ age anged be ween 18-30 yea s; b) s udies analysed expe ienced li e s; c) pos - 82 ac i a ion po en ia ion was s udied in spo s wi h high equi emen s o he a e o o ce de elopmen ; d) he po en ia ion p o ocol was conduc ed wi h ba bell exe cises; e) p e- and pos -e alua ion was done wi h a esis ance exe cise, e ical jump o simila (i.e. squa jump, coun e mo emen jump o d op jump). In he s udies whe e olume was no di ec ly epo ed, i was calcula ed as ollows: olume = se s x epe i ions x kilog ams. Figu e 4. Flow cha o sea ch s a egy and selec ion o a icles 3.1.4 Quali y assessmen Ox o d’s le el o e idence108 and he Physio he apy E idence Da abase (PED o) scale109,110 we e used in o de o assess he me hodological quali y o he s udies included in he e iew. Ox o d’s le el o e idence anges om 1a o 5, wi h 1a being sys ema ic 83 e iews o high-quali y andomized con olled ials (RCT) and 5 being expe opinions. The PED o scale consis s o 11 di e en i ems ela ed o he scien i ic igo . Gi en ha assesso s a e a ely blinded and ha blinding pa icipan s is almos impossible, i ems 5- 7 (which a e speci ic o blinding) we e emo ed om he scale28. Wi h he emo al o hese i ems, he maximum esul on he modi ied PED o scale was 7 ( he i s i em is no included in he inal sco e) and he lowes , 0. Ze o poin s a e awa ded o a s udy ha ails o sa is y any o he included i ems and 7 poin s o a s udy ha sa is ies all he included i ems. 84 Table 1. Physio he apy E idence Da abase (PED o) a ings and Ox o d e idence le els o he included s udies. S udy 1 2 3 4 5 6 7 8 To al E idence le el And ews e al. (2016) Yes 1 1 1 1 1 1 1 7 1b Comyns e al. (2007) Yes 1 1 1 1 1 1 1 7 1b Dello Iacono e al. (2019) Yes 1 1 1 1 1 1 1 7 1b Do Ca mo e al. (2018) Yes 1 1 1 1 1 1 1 7 2b Gilbe & Lees (2007) Yes 1 1 1 1 1 1 1 7 1b Golas e al. (2017) Yes 1 1 1 1 1 1 1 5 2b Kildu e al. (2008) Yes 0 0 1 1 1 1 1 5 2b Kobal e al. (2019) Yes 0 0 1 1 1 1 1 5 2b K zysz o ik e al. (2020a) Yes 1 1 1 1 1 1 1 7 1b K zysz o ik e al. (2020b) Yes 1 1 1 1 1 1 1 7 1b K zysz o ik e al. (2020c) Yes 1 1 1 1 1 1 1 7 1b K zysz o ik and Wilk (2020) Yes 1 1 1 1 1 1 1 7 1b Lowe y e al. (2012) Yes 1 1 1 1 1 1 1 7 2b Mina e al. (2019) Yes 1 1 1 0 1 1 1 6 1b Poulos e al. (2018) Yes 1 1 1 1 1 1 1 7 1b Rea don e al. (2014) Yes 1 1 1 1 1 1 1 7 2b Thomas e al. (2015) Yes 1 0 0 1 1 1 1 5 2b I ems in he PED o scale: 1 = eligibili y c i e ia we e speci ied; 2 = subjec s we e andomly alloca ed o g oups; 3 = alloca ion was concealed; 4 = he g oups we e simila a baseline ega ding he mos impo an p ognos ic indica o s; 5 = measu es o 1 key ou come we e ob ained om 85% o subjec s ini ially alloca ed o g oups; 6 = all subjec s o whom ou come measu es we e a ailable ecei ed he ea men o con ol condi ion as alloca ed o , whe e his was no he case, da a o a leas 1 key ou come we e analysed by “in en ion o ea ”; 7 = he esul s o be ween-g oup s a is ical compa isons a e epo ed o a leas 1 key ou come; 8= he s udy p o ides bo h poin measu es and measu es o a iabili y o a leas 1 key ou come 85 3.2 Publica ion 2: In e mi en Volun a y Isome ic Con ac ions E ec s on Pe o mance Enhancemen and S icking Region Kinema ics in he Bench P ess 3.2.1 Pa icipan s Twen y-one pa icipan s (age 26.4 ± 5.4 yea s; body mass 79.4 ± 9.7 kg; body heigh 176.2 ± 6.9 cm; medium g ip bench p ess 1 epe i ion maximum (1RM) 97.4 ± 19.8 kg; ela i e s eng h (1RM/body mass) 1.22 ± 1.9) wi h a leas wo yea s o esis ance aining expe ience olun a ily ook pa in his s udy. Pa icipan s we e equi ed o mee he ollowing inclusion c i e ia: 1) men be ween he age o 18–40 yea s; 2) lack o musculoskele al diso de s o inju y in he p e ious 6 mon hs; 3) expe ienced in esis ance aining, de ined as consis en ly li ing weigh s a leas 3 imes pe week o a minimum o 2 yea s. A o al o 20 pa icipan s comple ed he s udy: one pa icipan d opped ou p io o comple ion due o pe sonal easons. We did no con ol o nu i ion no hyd a ion le els, bu pa icipan s we e old no o make any changes in he abo e du ing he es ing pe iod. Pa icipan s we e asked o e ain om aining 48 h be o e each es ing session and no o ake ca eine. All pa icipan s pe o med he h ee sessions a he same ime o he day wi h a leas 48 h o es be ween sessions. W i en in o med consen was ob ained om each pa icipan a e a ho ough explana ion o he es ing p o ocol, he possible isks in ol ed, and he igh o e mina e pa icipa ion a will. The s udy was conduc ed acco ding o he Decla a ion o Helsinki111, and he Ins i u ional Re iew Boa d o he Uni e si y o he Basque Coun y (UPV/EHU) app o ed he expe imen al p o ocol. 86 3.2.2 P ocedu es Pa icipan s isi ed he labo a o y on h ee sepa a ed occasions. P io o e e y expe imen al session and he 1RM es , pa icipan s pe o med a s anda dised wa m-up p o ocol, consis ing o 5 min o cycling and bench p ess wa m-up se s consis ing o 1 se o 12 epe i ions wi h he ba bell only, ollowed by 3 se s o 8, 6 and 3 epe i ions wi h 40%, 60% and 75% 1RM, espec i ely. The es in e al be ween wa m-up se s was o 2 min. In e e y session, du ing he bench p ess, pa icipan s pe o med he descen wi h a 2 s empo, ollowed by a 1 s pause in he ches wi h help o a me onome a 60 bea s pe minu e (BPM) o s anda dise epe i ions. Pa icipan s we e ins uc ed o pe o m he concen ic phase as as as possible. Bench p ess g ip wid h was se a 1.4 imes biac omial dis ance as desc ibed elsewhe e 89. 3.2.2.1 1RM calcula ion Du ing he i s isi , pa icipan s unde wen a di ec 1RM es o he bench p ess. The 1RM was de ined as he highes load li ed by pa icipan s wi hou any compensa o y mo emen and only i hey comple ed he pause on he ches p ope ly. When an a emp was success ul, he nex a emp was decided asking he pa icipan and e alua ing he epo ed mean p opulsi e eloci y by he eloci y linea (Speed4Li s, Spain) 112. Pa icipan s es ed o 3 min be ween a emp s. The es inished when pa icipan s epo ed a a e o pe cei ed exe ion (RPE) o 10 in he epe i ions in he ese e based RPE scale 54. I pa icipan s ailed an a emp , he weigh was educed by 2.5 kg and ano he a emp was pe o med a e a 3 min es in e al. 87 3.2.2.2 S icking egion iden i ica ion In addi ion, each li on amilia iza ion was eco ded om a side iew a 300 Hz using an ac i e LED ma ke on he ba bell’s edge and a high-speed ideo came a (Casio ExilimEX-F1). Video eco dings we e analysed using kinema ic analysis so wa e Kino ea ( e sion 0.8.15), which is alid, p ecise, and eliable 113. Da a expo ed om Kino ea o Excel ( e sion 16.16.27) we e il e ed (Bu e wo h low pass il e a 5Hz) and hen used o de e mine whe e he s icking egion was, de ined as he egion o he li be ween he i s peak (Vmax peak) in eloci y and he i s minimum a e he peak (Vmin peak) 114. This egion di e s in e -indi idually due o di e ences in ana omical c oss- sec ional a ea o he muscle, o ce-leng h ela ionship, o ce- eloci y ela ionship, a igue, mo o uni ec ui men , ibe ype and biomechanical ac o s ha a ec o que de elopmen 20. Once he s icking egion was de ec ed, he heigh o he ba bell a his egion was calcula ed. Since he s icking egion is no a speci ic poin , bu a ange o mo ion o he li , o ensu e ha he isome ic con ac ion a ec ed he s icking egion, he p o ocol was pe o med in he middle o his egion, as isome ic con ac ions had been demons a ed o s eng hen 20º-50º away om he adop ed join angles 4. 3.2.2.3 Condi ioning Ac i i ies Measu emen s o he expe imen al condi ions las ed 45 minu es and we e scheduled one week a e he i s isi o he labo a o y. The s udy ollowed a wi hin-pa icipan design, whe e each pa icipan was his own con ol. In his way, in bo h expe imen al sessions 88 pa icipan s pe o med a p e-condi ioning li (con ol li ), a condi ioning ac i i y and se e al pos -condi ioning li s. Thus, he second day, pa icipan s we e andomly assigned o one o he ollowing wo expe imen al condi ions: an isome ic con ac ion condi ioning p o ocol (ISO) o a adi ional condi ioning p o ocol (TRAD). Volume was no ma ched be ween condi ioning ac i i ies. On he hi d session, pa icipan s changed expe imen al condi ions. A e comple ing he condi ioning p o ocol (ISO o TRAD), pa icipan s we e asked o RPE. Figu e 5. Scheme o ollowed in es iga ion p ocedu e Each expe imen al session consis ed o he s anda dised wa m-up p o ocol ollowed by a 3-min es in e al and a p e-condi ioning li (con ol li ), which consis ed o 1 se o 1 epe i ion o he bench p ess a 85% 1RM. A e he p e-condi ioning li , pa icipan s es ed 3 min and hen hey p oceeded wi h he condi ioning ac i i y o which hey we e andomly assigned. 89 The ISO condi ioning ac i i y consis ed o 15 maximal olun a y isome ic con ac ions (MVIC) o 1 s wi h 1-s es in e al be ween con ac ions5 a hei s icking egion as p e iously desc ibed. Pa icipan s we e encou aged o exe o ce as as as possible. Isome ic con ac ions we e pe o med by ixing he ba bell o a Smi h machine a he app op ia e heigh (using a 11mm diame e ock climbing ope) o ma ch he middle o he s icking egion heigh . The TRAD condi ioning ac i i y consis ed o 1 se o 1 epe i ion wi h 93% o hei es ima ed 1RM o he amilia isa ion day1. Pos -condi ioning measu emen s (1 se o 1 epe i ion o he bench p ess a 85% 1RM) we e eco ded 0, 4, 8, 12 and 16 minu es la e (pos 0, pos 4, pos 8, pos 12 and pos 16)103,115 using he same eloci y linea ansduce . Pa icipan s we e ins uc ed o li he ba bell as as as possible du ing he ascending phase o he mo emen . I pa icipan s imp o ed pe o mance om p e-condi ioning o any o he pos - condi ioning li s, hey we e chosen o u he analysis o he s icking egion kinema ics. This dis inc ion be ween esponde s and non- esponde s o condi ioning ac i i y was based on he calcula ed smalles meaning ul di e ence. When he di e ence in he bes pos -condi ioning li and he p e-condi ioning li was highe han he smalles meaning ul di e ence, pa icipan s we e conside ed esponde s and chosen o analysis o he s icking egion. 90 3.2.3 S a is ical Analyses Da a we e sc eened o no mali y o dis ibu ion using he Shapi o-Wilk es . Two-way ANOVA wi h epea ed measu es (li x ime) was used o de e mine i any o he pos - condi ioning li s imp o ed pe o mance unde each expe imen al condi ion and o compa e same ime poin ac oss expe imen al condi ions (ISO s. TRAD). The magni ude o di e ences o e ec sizes (ES) we e calcula ed using Cohen’s d 116 and in e p e ed as small (>0.2 and <0.6), mode a e (≥0.6 and <1.2) and la ge (≥1.2 and <2) o e y la ge (≥2) acco ding o Hopkins e al. (2009) 117. All s a is ical analyses we e pe o med using P ism 9 o Mac. Signi icance o all analyses was se a p < 0.05. 95% con idence in e als a e epo ed as 95% [Lowe limi , Uppe limi ]. Addi ionally, o hose pa icipan s o whom he condi ioning ac i i y imp o ed pe o mance ( esponde s), he eloci y un il he i s peak in eloci y was measu ed and compa ed using one-way ANOVA wi h epea ed measu es (li x ime), compa ing p e-condi ioning eloci y, pos 0 eloci y and eloci y o he as es ime poin . To selec hose esponde s, we calcula ed he smalles meaning ul di e ence ollowing he o mula below: , 2·." /·!(1#$% +1#$& ") The epo ed esul s by he o mula we e smalle (e.g., measu ed smalles meaning ul di e ence = 0.005 m·s-1) han alues epo ed by he used eloci y linea ansduce (e.g., 0.23 m·s-1). Thus, i any pa icipan imp o ed pe o mance in any pos -condi ioning li (e.g., om 0.23 m·s-1 o 0.24 m·s-1), he di e ence mus ha e been highe han he calcula ed smalles meaning ul di e ence. We also pe o med a Fishe ´s exac es o 97 4. RESULTS 4.1 Publica ion 1: Pos -ac i a ion po en ia ion in s eng h aining: A sys ema ic e iew o he scien i ic li e a u e 4.1.1 S udies Selec ed The sea ch s a egy yielded 202 o al ci a ions as p esen ed in Figu e 1. F om hose 202 a icles, 17 me he inclusion c i e ia. Excluded s udies had a leas one o he ollowing cha ac e is ics: he po en ia ion p o ocol included s a egies di e en om esis ance aining (e.g., elec os imula ion o ib a ion), pa icipan s we e no expe ienced li e s (had less han 2 yea s o esis ance aining expe ience o less han 2 x bodyweigh squa 1-RM) o he e alua ion p o ocol was done wi h sp in ing bou s (Table 1). 4.1.2 Le el o E idence and Quali y o he S udies Ten o he se en een included s udies had a le el o e idence 1b (good quali y andomized con ol ials). The 7 emaining s udies had a le el o e idence o 2b (indi idual coho s udies). Also, he mean sco e in he PED o scale was 6.47 ± 0.87, wi h alues anging om 5 o 7 (Table 1). 4.1.3 Cha ac e is ics o he Pa icipan s Pa icipan s we e cha ac e ized as expe ienced o well- ained a hle es due o hei aining expe ience o hei one epe i ion maximum ( he maximum amoun o weigh ha a pe son is able o li o one epe i ion). A summa y o pa icipan s´ cha ac e is ics 98 is p esen ed in Table 2. The o al numbe o pa icipan s was 279 (253 men, 6 women and 20 unknown). Table 2. Included s udies S udy Numbe (M/F) Age (yea s) RT expe ience (yea s) Main Ou come And ews e al. (2016) 14 (8/6) M 21.3 ± 1.8 / F 21.2 ± 0.4 ≥ 2 Unila e al PAP and a igue Comyns e al. (2007) 12 (12/0) 23.3 ± 2.5 1RM ≥ 2x bodyweigh Op imal esis i e load and PAP Dello Iacono e al. (2019) 26 (26/0) 23.2 ± 5.1 ≥ 2 T adi ional se s PAP s clus e se s PAP Do Ca mo e al. (2018) 12 (12/0) 25.4 ± 3.6 ≥ 3 PAP es in e al Gilbe and Lees (2007) 15 (15/0) 24.3 ±3.3 unknown Changes in o ce de elopmen Golas e al. (2017) 16 (16/0) 18-35 ≥ 5 Used PAP load magni ude Kildu e al. (2008) 20 (Unknown) 25.4 ± 4.8 3.1 ± 1.6 Reco e y ime and PAP Kobal e al. (2019) 18 (18/0) 25.42 ± 3.58 3 Di e en olume and PAP K zysz o ik e al. (2020a) 12 (12/0) 25.2 ± 2.1 3 PAPE and aining olume K zysz o ik e al. (2020b) 32 (32/0) 28.4 ± 4.5 3 Eccen ic and concen ic PAP K zysz o ik e al. (2020c) 13 (13/0) 25.7 ±1.9 6.5 ± 2.2 Eccen ic PAP K zysz o ik and Wilk (2020) 24 (24/0) 24.5 ± 2.6 6.3 ± 2.5 Plyome ic PAP p o ocol Lowe y e al. (2012) 13 (13/0) 21 ± 3 3 PAP s imuli and eco e y ime Mina e al. (2019) 15 (15/0) 21.7 ± 1.1 ≥ 5 PAP: ee weigh s a iable esis ance Poulos e al. (2018) 15 (15/0) 24.3 ± 2.6 ≥ 2 Back Squa in ensi y and PAP Rea don (2014) 11 (11/0) 25.18 ± 3.60 1RM ≥ 2x bodyweigh Muscle a chi ec u e and PAP Thomas e al. (2015) 11 (11/0) 23 ± 4 ≥ 2 PAP and neu omuscula unc ion PAP = pos ac i a ion po en ia ion; M = male; F = emale; RT = esis ance aining 99 4.1.4 S udies ma ching olume load Fi e o he included 17 s udies ma ched he olume load in he p o ocols used. F om hese i e s udies, h ee compa ed di e en in ensi y p o ocols103,115,119 and wo he op imal es in e al32,40. Mina e al. (2019)103 pe o med a s udy compa ing ee weigh back squa s and a iable esis ance back squa s (elas ic bands we e used o gene a e he 35% o he o al load a he uppe pa o he squa ). Unde he ee weigh condi ion, no signi ican changes we e ound in jump heigh , peak powe o a no malized ( o body weigh ) a e o o ce de elopmen (RFD) compa ed o p e-in e en ion pe o mance. On he o he hand, unde he a iable esis ance condi ion, s a is ically signi ican inc eases (p < 0.05) in CMJ heigh we e obse ed a 30s (5.9 ± 1.2%), 4 min (5.6 ± 1.8%), 8 min (6.5 ± 2.6%) and 12 min (5.3 ± 2.5%) compa ed o p e-in e en ion. In addi ion, s a is ically signi ican inc eases (p < 0.05) we e e iden in peak powe a 30s (4.7 ± 1.2%), 4 min (5.9 ± 1.3%), 8 min (4.4 ± 1.7%) and 12 min (4.8 ± 1.7%) ime poin s. These changes in CMJ heigh and peak powe we e also signi ican ly di e en om he ee weigh condi ion g oup (p < 0.05). Dello Iacono e al. (2019)119 compa ed he e ec o wo p o ocols using he indi idualized op imal powe load wi h adi ional and clus e -se con igu a ion in a andomized c oss- o e design. Al hough bo h p o ocols inc eased jump heigh 4 and 8 min pos - in e en ion, he clus e se con igu a ion eached signi ican ly be e esul s by 1.33 cm (95% CI, 1.02 o 1.65 cm) and 1.64 cm (95% CI, 1.41 o 1.88 cm), espec i ely. 100 Addi ionally, clus e se con igu a ion was able o main ain 10% highe powe ou pu (95% CI, 8 o 12%) ela i e o hei ela i e mean p opulsi e powe . Lowe y e al. (2012)115 s udied he e ec s o h ee di e en loads (ligh , 56% 1RM; medium, 70% 1RM; and hea y, 93% 1RM) on e ical jump heigh . Ve ical jumps a e he ligh load p o ocol did no each s a is ically signi ican di e ences. Mode a e and high load p o ocols dec eased e ical jump pe o mance igh a e he condi ioning ac i i y (p < 0.05; ESmedium loaded = -2.45, la ge; EShea y loaded = -2.87, la ge). Addi ionally, a medium loaded p o ocol eached a signi ican pe o mance inc ease a 4 min in he pos ac i a ion aining p o ocol (p < 0.05; ES = 1.46, la ge) and a high loaded p o ocol eached s a is ically signi ican imp o emen s a bo h 4 and 8 min pos p o ocol (p < 0.05; ES4min = 1.34, la ge; ES8min = 1.48, la ge). Kildu e al. (2008)40 a emp ed o se he op imal eco e y ime o a complex aining session. Pa icipan s pe o med 3 se s o 3 epe i ions a 87% 1RM back squa s be o e an explosi e ac i i y. They epo ed a s a is ically signi ican (p < 0.05) dec ease a 15s pos condi ioning ac i i y and a s a is ically signi ican (p < 0.05) inc ease a 8 min pos condi ioning ac i i y o powe ou pu and o jump heigh . A s a is ically signi ican (p < 0.05) inc ease in he RFD 8 min pos condi ioning ac i i y was also epo ed. Addi ionally, Do Ca mo e al. (2018)32 sugges ed ha sel -selec ed es in e als we e be e han a ixed es in e al in o de o dissipa e he a igue c ea ed by he condi ioning ac i i y. They conduc ed a s udy, and no signi ican changes we e obse ed a e he condi ioning ac i i y in he ixed es in e al g oup (38.0 ± 5 cm s. 37.7 ± 5.1 cm; p = 0.4; ES = 0.04) no in he sel -selec ed es in e al g oup om p e- o pos - es (38.2 ± 4.6 cm s. 40.5 ± 4.4 cm). 101 4.1.5 S udies no ma ching olume load The emaining wel e o he included 17 s udies did no ma ch he olume load in he p o ocols used. Fou o hese s udies6,38,41,120 suppo he ela ionship be ween a highe olume load and po en ia ion s imuli. O he emaining 8 s udies, one analysed he neu omuscula unc ion121, compa ed PAP in exe cised and con ala e al legs122, compa ed he ela ionship be ween PAP and ime unde ension50 and ano he s udied he e ec s o plyome ic PAP in bench p ess h ow123. The emaining 4 epo ed con adic o y esul s39,106,124,125. Fou s udies6,38,41,120 suppo he no ion o highe olume loads as be e po en ia ion s imuli. These ou s udies compa ed di e en in ensi ies and olumes anging om 65% 1 RM o 130% 1 RM. Gilbe and Lees (2005)38 ound s a is ically signi ican inc eases in he isome ic RFD in he 1RM g oup a 15 min (p = 0.021) and 20 min (p = 0.006), wi h a peak inc ease o 11.8%. In he op imal powe load g oup, a s a is ically signi ican inc ease (p = 0.038) in he isome ic RFD was ound a 2 min, wi h a peak inc ease o 6.7%. Comyns e al. (2007)120 ound ha con ac ime showed a s a is ically signi ican educ ion (p < 0.05) and e ical leg sp ing s i ness indica ed a signi ican inc ease (p < 0.05) o he hea y loaded p o ocol (93% 1RM). Howe e , he e we e signi ican ly (p < 0.01) sho e ligh imes o all he p o ocols. K zysz o ik e al. (2020)6 compa ed he di e ences be ween a classic PAP p o ocol (2 se s o 2 epe i ions o concen ic bench p ess a 90% 1-RM) and eccen ic p o ocols (2 se s o 2 epe i ions o ei he only eccen ic 90% 1-RM, only eccen ic 110% 1-RM o only eccen ic 130% 1-RM bench p ess). The s udy epo ed be e po en ia ion esul s wi h eccen ic only p o ocols, achie ing g ea e peak eloci y (η2 = 0.441; p = 0.019) and g ea e mean eloci y (η2 = 0.011; p = 0.041) 102 a e he 110% 1-RM eccen ic only p o ocol and g ea e peak eloci y a e he 130% 1- RM eccen ic only p o ocol (η2 = 0.323; p = 0.037). In ano he s udy by K zysz o ik e al. (2020)41 wi h he same eccen ic p o ocols, he bench p ess h ow wi h a load o 30% 1-RM imp o ed peak powe by 10.5 ± 6.0% (e ec size = 0.34) and by 9.9 ± 8.1% (e ec size = 0.33) o he 110 and 130% 1-RM condi ions, espec i ely. Peak eloci y inc eased by 5.9 ± 5.5% (e ec size = 0.4) and by 6.1 ± 6.1% (e ec size 0.43) o he 100 and 130% 1-RM p o ocols, espec i ely. Since se s and epe i ions emained he same h ough p o ocols, he di e ences in olume load we e a esul o he di e en in ensi ies. Fou s udies39,106,124,125 showed con lic ing esul s. In he s udy by Poulos e al. (2018)106 bo h p o ocols (10 se s o 3 o 5 epe i ions wi h 87% 1RM s. 65% 1RM espec i ely) enhanced jump heigh (65% 1RM: +3.3 ± 2.2% [CI: 1.0 o 5.6]; 87% 1RM +2.6% ± 1.9% [CI: 0.7 o 4.5]) a e 10 se s. Ne e heless, he e was a la ge chance o jump heigh imp o emen when CMJs we e pe o med ac oss he 10 se s o squa s in he p o ocol o 87% 1RM. Golas e al. (2017)39 compa ed i e di e en p o ocols and hey obse ed s a is ically signi ican (p = 0.01) di e ences in he RFD and he a e o powe de elopmen (RPD) (p = 0.02) in he medium olume load g oup (80% 1RM) compa ed o he o he condi ions. Addi ionally, Kobal e al. (2019)124 ound ha a lowe olume load wi h a highe in ensi y (100% 1RM) p o ocol induced simila esul s o a highe olume load and ligh e load p o ocol (93% 1RM and 87% 1RM). Rea don e al. (2014)125 ound no pe o mance imp o emen in any o hei p o ocols (3 se s o ei he 10 o 3 epe i ions wi h 75% 1RM s. 90% 1RM). Thomas e al. (2017)121 analysed neu omuscula unc ion using EMG du ing a PAP p o ocol. Coun e mo emen jump heigh inc eased signi ican ly (p = 0.008) om p e- o 103 pos -po en ia ion ( om 41.0 ± 4.3 cm o 44.7 ± 4.1 cm). Neu omuscula unc ion was measu ed be o e he i s CMJ and a e he las CMJ. A small and s a is ically non- signi ican dec ease in he maximum olun a y con ac ion (MVC) (p = 0.142) and in olun a y ac i a ion (p = 0.06) was obse ed, bu po en ia ed wi ch o ce was signi ican ly (p < 0.001) educed a e s eng h aining (235 ± 65 N o 185 ± 51 N) in compa ison o he con ol g oup. And ews e al. (2016)122 s udied he e ec o unila e al squa s po en ia ion in he exe cised leg and in he con ala e al leg using a low a igue p o ocol. The esul s showed no s a is ically signi ican di e ences a 1, 5 and 10 min in compa ison o p e- es alues o he d op jump con ac ime o he d op jump eac i e s eng h index. Rega ding he CMJ, a condi ion x ime in e ac ion indica ed ha he exe cised leg exhibi ed signi ican bu small o i ial magni ude jump heigh inc eases o 4.0% (p = 0.02; d = 0.36), 0.9% (p = 0.06; d = 0.08) and 1.6% (p = 0.04; d = 0.15) a 1, 5 and 10min pos -in e en ion, espec i ely. The con ala e al leg, on he o he hand, had i ial CMJ de ici s pos in e en ion: 1.3% (p = 0.23; d = 0.12), 0.9% (p = 0.09; d = 0.10) and 1.7% (p = 0.03; d = 0.19) a 1, 5 and 10min pos -in e en ion, espec i ely. K zysz o ik and Wilk (2020)123 showed ha 3 se s o 5 epe i ions o plyome ic push ups wi h 1 min es in e al imp o ed bench p ess peak eloci y (p < 0.01) and mean eloci y (p < 0.01) compa ed o a con ol g oup. In addi ion, K zysz o ik e al. (2020)50 also ound ha a PAP p o ocol consis ing o 3 se s o 3 epe i ions a 85% 1-RM achie ed highe aining olume based on ime unde ension a he end o he aining session (p < 0.01) when compa ed o a con ol g oup, despi e comple ing he same numbe o epe i ions. 104 4.2 Publica ion 2: In e mi en Volun a y Isome ic Con ac ions E ec s on Pe o mance Enhancemen and S icking Region Kinema ics in he Bench P ess 4.2.1 Kinema ics o he s icking egion To analyse he changes in he kinema ics o he s icking egion, subjec s who imp o ed pe o mance in any ime poin (i.e., esponde s) we e analysed, e en i s a is ical signi icance was no eached. The Fishe ´s exac es epo ed a signi ican di e ence be ween he numbe o esponde s and non- esponde s (p = 0.001). Thus, se en subjec s we e analysed o he TRAD condi ion and 17 o he ISO condi ion. When compa ing mean eloci y om he s a o he ascending phase un il he i s maximum peak in eloci y (p e-s icking egion), no di e ences we e ound in he TRAD expe imen al condi ion o he esponde s (n = 7; 33.33% o pa icipan s) (p = 0.229; 95% CI [−0.1545, 0.035]) (Figu e 6A). 105 Figu e 6 Li ing eloci ies p e-condi ioning and in he slowes - and as es pos -condi ioning ac i i y ime poin s. (A) TRAD pos -ac i a ion pe o mance enhancemen expe imen al session. (B) ISO pos -ac i a ion pe o mance enhancemen expe imen al session. * p < 0.05; ** p < 0.001 In con as , when compa ing he eloci y om he s a o he ascending phase un il he i s maximum peak in eloci y unde he ISO expe imen al condi ion in he same ime poin s, we ound ha o esponde s (n = 17; 85% o pa icipan s), he i s maximum peak in eloci y was highe in he as es ime poin (i.e., highe eloci ies we e achie ed 106 p io o he ini ia ion o he s icking egion) (p < 0.001; ES = 0.67; 95% CI [0.07, 0.02]). Howe e , when compa ing he i s maximum peak in eloci y om p e- wi h he i s maximum peak in eloci y in he slowes ime poin (pos 0), we ound ha in he slowes ime poin , he i s maximum peak was smalle (lowe eloci ies we e eco ded p io o he ini ia ion o he s icking egion) (p = 0.004; ES = 0.64; 95% CI [-0.012, -0.063]). Addi ionally, he ascending phase eloci y un il he i s maximum peak in he as es ime poin was highe han in he pos 0 ime poin (p < 0.0001; ES = 1.22; 95% CI [0.112, 0.053]) (Figu e 6B). We compa ed Vmax peak and Vmin peak om p e- o he as es pos -condi ioning li o each pa icipan o whom ei he he TRAD o he ISO expe imen al condi ion was e ec i e. The TRAD expe imen al condi ion showed no imp o emen s in Vmax peak (p = 0.457; ES = 0.37; 95% CI [-0.074, 0.146]) no in Vmin peak (p = 0.125; ES = 0.85; 95% CI [-0.0271, 0.173]), while he ISO expe imen al condi ion showed imp o emen s in bo h Vmax peak (p = 0.005; ES = 0.71; 95% CI [0.02, 0.093]) and Vmin peak (p = 0.025; ES = 0.38; 95% CI [0.006, 0.072]) (Figu es 7A–D). 113 5. DISCUSSION 5.1 Publica ion 1: Pos -ac i a ion po en ia ion in s eng h aining: A sys ema ic e iew o he scien i ic li e a u e The main inding o his sys ema ic e iew is ha he olume load plays an impo an ole in pe o mance enhancemen a e a condi ioning ac i i y. Fou s udies i mly suppo ha he olume load is he main condi ioning ac o o achie e an op imal po en ia ion e ec 6,38,41,120, while ou showed con adic o y esul s39,106,124,125. This sys ema ic e iew also shows ha when he o al olume is low, in ensi y seems o be decisi e106,122. Rec ui men o ype II ibe s is needed o achie e po en ia ion, which is he esul o combining olume and in ensi y126–129. As s a ed by Schoen eld (2010)22, in o de o ec ui high o de mo o uni s, ligh loads a e no as e ec i e as hea y loads. In he ou s udies6,38,41,120 i mly suppo ing ou hypo hesis, high in ensi ies we e used (up o 130% 1 RM) o achie e highe olume loads. Howe e , po en ia ion can be achie ed using lowe olume loads as well39,124. Gołas e al. (2017)39 and Kobal e al. (2019)124 pe o med be ween 3 and 5 se s wi h di e en loads anging om 60% 1 RM o 100% 1- RM wi h a ixed es in e al. Conside ing ha a igue is especially e iden when aining is pe o med close o 1-RM o o ailu e26,130, he be e po en ia ion achie ed in hese s udies wi h lowe olume loads may ely on he es - ime be ween he condi ioning ac i i y and he e- es . Al hough acco ding o Do Ca mo e al. (2018)32 a sel -selec ed es may be su icien o imp o e pe o mance, o he s udies sugges ha po en ia ion alues peak a e 8 min o longe es ing pe iods38,40. 114 The second inding is ha a minimum e ec i e in ensi y is needed o achie e po en ia ion. Howe e , in ensi y should be unde s ood as he numbe o epe i ions in ese e and no as he pe cen age o 1-RM. In o de o achie e po en ia ion, we can ei he use ligh loads wi h high olumes o high in ensi ies wi h low olumes127. Thus, when lea ing a leas 2 epe i ions in ese e, pe o ming mul iple se s leads o po en ia ion wi hou accumula ing excessi e a igue106,122. Howe e , al hough lowe ing in ensi y du ing he condi ioning ac i i y may lead o lesse a igue103, lea ing oo many epe i ions in ese e may no p o ide enough s imuli o elici po en ia ion54,125. On he o he hand, lea ing oo ew epe i ions in ese e (be ween 0 and 1) may lead o excessi e a igue and impai ed pe o mance a e he condi ioning ac i i y 54,125. In his way, he highe he in ensi y, he longe he es in e al he a hle e needs o dissipa e a igue32,38. We also ound di e en ime-po en ia ion p o iles o high- and medium-load p o ocols. In he s udy by Lowe y e al. (2012)115, hea y and medium p o ocols peaked a he same ime poin , bu po en ia ion achie ed wi h he hea y loaded p o ocol was main ained o a longe ime. These indings a e in line wi h hose o Gilbe and Lees (2005)38, who epo ed di e en ime-po en ia ion p o iles; while he op imal powe load g oup peaked ea lie , he hea y loaded p o ocol g oup peaked la e bu wi h a highe po en ia ion e ec (6.7% s. 11.8%, espec i ely). These indings a e in line wi h hose by K zysz o ik and Wilk (2020)123, who obse ed he g ea e inc ease in peak eloci y and mean eloci y o he bench p ess in he i s se a e he plyome ic push ups p o ocol. Thus, he ime- po en ia ion p o iles seem o be de e mined by he in ensi y o he s imuli and he es ing ime ( a igue-po en ia ion ela ionship). Fa igue in esis ance aining, as sugges ed by Zajac e al. (2015)130, is p oduced by pos -exe cise in amuscula pe u ba ions (i.e., dec ease in phosphoc ea ine, glycogen, ATP s o es and augmen a ion o phospha e and 115 hyd ogen ions) and modula ion o cen al mo o d i e du ing exe cise by nocicep i e a e en inpu (III and IV muscle a e en s). These changes a e especially e iden when aining sessions a e close o 1-RM. Du ing submaximal con ac ions, he close o ailu e, he mo e mo o uni s a e ec ui ed, bu also he highe he me aboli e accumula ion, which con ibu es o a igue26. This may pa ially explain he di e ences in he po en ia ion p o ocols lea ing oo many122 o oo li le125 epe i ions in ese e du ing submaximal e o s. We ha e o acknowledge se e al limi a ions. These include he lack o aw da a o a deepe analysis. The main pu pose o he e iew was o summa ize he e idence so a and, i possible, o analyse di e ences in used p o ocols based on he olume load. While he mos ecen s udies included aw da a, he oldes ones did no . This limi ed ou in en ion o compa e he olume load o di e en p o ocols as we could no calcula e i o 2 o he 13 s udies. Ano he impo an limi a ion was ela ed o he he e ogenei y o he p o ocols used. Finally, he esul s o his e iew canno be ex apola ed o he gene al popula ion as i only analysed ained subjec s and almos all subjec s we e men. All hese limi a ions imply ha he conclusions o his e iew should be in e p e ed wi h cau ion. 5.2 Publica ion 2: In e mi en Volun a y Isome ic Con ac ions E ec s on Pe o mance Enhancemen and S icking Region Kinema ics in he Bench P ess The indings o his s udy suppo one o ou wo hypo heses, i.e., he kinema ics and he cha ac e is ics o he s icking egion change conside ably (Figu e 11 A-C) a e he ISO condi ioning p o ocol, howe e , mean p opulsi e eloci y emains unchanged. 116 The main inding o his s udy was ha an isome ic PAPE p o ocol imp o ed s icking egion kinema ics in he i s pa o he ange o mo ion o he medium g ip bench p ess. This imp o emen is e iden in he i s pe iod o he ascending phase, p io o he s icking egion, which helps he li e o o e come ha s icking egion 20. The main enhancemen is ha he i s maximum eloci y peak is g ea e a e he ISO condi ioning p o ocol (Figu e 7C), which p o ides he li e wi h a g ea e impulse o o e come he s icking egion. Also, he minimum eloci y is highe a e he ISO condi ioning p o ocol (Figu e 7D). The augmen ed i s maximum and minimum eloci y peaks esul in a change in he eloci y- ime p o ile o he li (Figu e 11 A-C). This change in he eloci y- ime p o ile o he li and he s icking egion (i.e., less eloci y loss om maximum o minimum eloci y poin s) is due o he g ea e impulse ha he li e has achie ed p io o he s icking egion. The imp o emen in he i s pa o he li can p o ide he li e wi h enough impulse o a oid excessi e eloci y loss om Vmax peak o Vmin peak, making he s icking egion impe cep ible (Figu e 11C). 117 Figu e 11. (A) Illus a ion o a ypical S icking Region eloci y- ime p o ile, which could be obse ed in p e- condi ioning li s. (B) Illus a ion o a S icking Region eloci y- ime p o ile pos -condi ioning, wi h enhanced he i s peak in he eloci y o he load (Vmax) and i s i s local minimum peak he ea e (Vmin). (C) Illus a ion o a pos - condi ioning li whe e he impulse p io o he ini ia ion o he S icking Region is augmen ed o he poin ha no eloci y loss occu s and, hus, Vmin disappea s. The ISO condi ioning p o ocol imp o ed pe o mance in mo e pa icipan s (85%) han he adi ional condi ioning p o ocol (33.33%), which could be ela ed o he in e ac ion be ween s imuli and a igue 17. Rec ui men o ype II ibe s is needed o achie e PAPE, which is he esul o a co ec selec ion o in ensi y 1. The TRAD condi ioning p o ocol implied a highe RPE han he ISO condi ioning p o ocol (ES = 0.36). None heless, in bo h condi ioning p o ocols pa icipan s epo ed an RPE 7, which is in line wi h p e ious li e a u e 1. The ISO condi ioning p o ocol includes 1-second es in e als, which ia he educ ion in ino ganic phospha e accumula ion could help educe excessi e a igue 5. Is wo h men ioning ha he ISO condi ioning p o ocol p oduced g ea e dec ease in pe o mance immedia ely pos condi ioning (pos 0) compa ed o he TRAD p o ocol. This could be due o he o al ime unde ension, which is g ea e in he ISO condi ioning 118 p o ocol (15-seconds in o al). Howe e , in con as o he TRAD condi ioning p o ocol, imp o emen s in eloci y un il he ini ia ion o he s icking egion we e ound in he ISO condi ioning p o ocol, which sugges s ha isome ic con ac ions p oduce less a igue han dynamic con ac ions, o ha subjec s eco e om he p oduced a igue as e 4. This lowe cumula i e a igue may be due o he lowe consump ion o ATP in leng hened and isome ic con ac ions compa ed o sho ening con ac ions131. Rega ding he neu al ac o s limi ing maximal o ce p oduc ion, i is widely accep ed ha mo o uni ec ui men s a egies play a key ole 132. The o igin o his cen al a igue could be a spinal le el, due o inhibi o y in amuscula a e en s (i.e., g oup Ia and II muscle a e en s) and ecu en inhibi ion by Renshaw cells 133. We mus acknowledge some limi a ions. Conside ing ha a linea encode p o ides he mean p opulsi e eloci y 134 and ha he minimum mean p opulsi e eloci y o a success ul li on he bench p ess has been calcula ed 18, mo e eloci y implies mo e dis ance om ha mean minimum p opulsi e eloci y, and hus, u he s subjec s om ailu e. Un o una ely, changes in magni ude (e.g., om 0.27 m·s-1 o 0.29 m·s-1) we e so small ha s a is ical signi icance was no eached. Ne e heless, when compa ing ins an aneous eloci ies, magni ude changes we e g ea e (e.g., om 0.26 m·s-1 o 0.34 m·s-1). Also, he selec ed in ensi y o he con ol li (85% 1RM) was high. E en i no o ious mean p opulsi e eloci y changes a e ha d o see a hose in ensi ies, 85% 1RM was chosen o wo main easons: (i) highe simila i y o a eal s eng h aining o compe i ion and (ii) his is he minimum in ensi y needed o eco d a s icking egion 96, which was one o he in en ions o he s udy. Finally, i is wo h men ioning ha his s udy does no include a classic con ol g oup wi h no condi ioning ac i i y ca ied ou . These limi a ions imply ha conclusions o his s udy should be in e p e ed wi h cau ion. 119 5.3 Publica ion 3: Pos -Ac i a ion Pe o mance Enhancemen as a s a egy o imp o e bench p ess pe o mance o oli ional ailu e The main inding o his s udy was ha pe o ming a adi ional PAPE p o ocol consis ing o a single se o a single epe i ion wi h he 93% 1RM 1 imp o ed bench p ess pe o mance, measu ed as numbe o epe i ions o oli ional ailu e. These esul s a e in ag eemen wi h p e ious esea ch 49. Pe o ming a adi ional PAPE p o ocol p io o a se o oli ional ailu e could make he a hle e acu ely mo e esis an o a igue in long-las ing asks (in ou case, a se o oli ional ailu e o a ious epe i ions) 127. The exac a ionale behind his imp o emen in pe o mance is no ully elucida ed. Tempe a u e aises a e a commonly men ioned mechanism behind pe o mance enhancemen , bu based on he esul s o Weige e al. (2018) 81, whe e small and non-signi ican empe a u e changes we e seen a e 10 epe i ions a 70% in a biceps cu l, i seems unlikely. Ne e heless, Boullosa e al. (2018)82 men ion a possible mechanism, whe e he ele a ion o Ca2+ le els inc ease due o low- equency wi ches, wha can cause he pe o mance enhancemen independen o myosin egula o y ligh chain phospho yla ion. In e es ingly, pe o mance imp o emen s obse ed in his s udy may be ela ed o imp o ed capaci y o pe o m slowe epe i ions, as unde he PAPE condi ion, pa icipan s pe o med, on a e age, one mo e epe i ion, which was slowe han unde he CON condi ion (Figu e 10). In consequence, he eloci y loss was g ea e om he i s o he las epe i ion. The a emp o comple e one mo e epe i ion so close o ailu e could 120 be due o psychological easons47. The maximal adap abili y heo y47 s a es ha hype s ess si ua ions could lead o bad pe o mance. In his way, hose las , ha d, and slow epe i ions would be he s essing si ua ions whe e pa icipan s need o s i e o ul il he li . Pe o ming he condi ioning ac i i y in he PAPE p o ocol (a hea y epe i ion p io o he es ed ask), could imp o e pa icipan s´ con idence when s uggling wi h hose las epe i ions 47. Ano he possible explana ion o he pe o mance imp o emen obse ed could be he aining eloci y speci ici y, which means ha a e pe o ming ha speci ic condi ioning ac i i y, pa icipan s gain acu e i ness o adap acu ely o low eloci y li ing 135. The quan i y o wo k pe o med pe session, unde s ood as o al numbe o se s 27, o he olume load (se s x epe i ions x kilog am) 136 is ela ed o he quan i y o gained muscle mass. Thus, i PAPE leads o an inc eased numbe o epe i ions pe o med un il ailu e, olume load pe session would be imp o ed, and so could muscle hype ophy. Following his line o easoning, i could also be assumed ha hypo he ic muscle hype ophy bene i s could be due o bo h he imp o ed mechanical ension o he las epe i ion (due o ob ained lowe mean p opulsi e eloci ies, Figu e 10) and a g ea e numbe o pe o med epe i ions (Figu e 9). This means ha he pe o med addi ional epe i ion may be e ec i e when aiming a muscle hype ophy. P e ious s udies suppo he no ion ha wi h a g ea e eloci y loss, muscle hype ophy gains can be mo e signi ican 134, bu only o some ex en 137,138. E idence sugges s ha when eloci y loss is excessi e (40%), subsequen se s could be a ec ed138. This is in line wi h indings o Al es e al. (2019)49, whe e signi ican di e ences we e ound in he numbe o epe i ions pe o med in he i s (PAP = 11.5 ± 3.1; CON = 10.4 ± 2.7; p < 0.05; ES = 0.38) and he second (PAP = 6.5 ± 1.9; CON = 5.5 ± 1.8; p < 0.05; ES = 0.54) se be ween PAP and CON g oups, bu 121 no in he hi d se . This sugges s ha pe o mance enhancemen s can inc ease aining olume signi ican ly, bu when eloci y loss is oo p onounced, a igue may o e come po en ia ion and impai pe o mance in subsequen se s. Ou s udy is in line wi h ha by K zysz o ik, Wilk, Filip, e al. (2020)50, as inc easing he numbe o epe i ions led o highe ime unde ension. Based on his, u u e esea ch should add ess whe he a g oup pe o ming a PAPE p o ocol combined wi h a mode a e eloci y loss (i.e., 20% eloci y loss) can comple e mo e epe i ions han a con ol g oup o se e al se s ( ou o six se s). Fu he mo e, i he PAPE expe imen al condi ion g oup can pe o m mo e epe i ions, i would be in e es ing o ca y ou a long- e m in e en ion o examine whe he his p o ocol would b ing mo e muscle mass gain han a con ol condi ion. This s udy aced se e al limi a ions, including ela i ely small (n=12) sample size, which make i di icul o gene alise he ob ained esul s. Ou esul s p o e ha a PAPE p o ocol can be use ul o imp o e pe o mance in a ask o ailu e, which makes PAPE a po en ial s a egy o inc ease muscle hype ophy gains. Howe e , his was no measu ed, and he e o e, u he s udies a e wa an ed. Fu he mo e, ou s udy included only one se un il oli ional ailu e, howe e , he e ec o his se on pe o mance in subsequen se s was no e alua ed. 5.4 Gene al Discussion 5.4.1 Gene al concep s Conside ing all he in o ma ion abo e, he basis o any PAP o PAPE p o ocol a e bo h in ensi y and olume. This is no unexpec ed, because i manipula ion o hose wo 122 concep s is o pa amoun impo ance when c ea ing a aining s imulus o any du a ion (a session, mic ocycle, mesocycle, mac ocycle o any leng h cycle)16,17, why should i be di e en when conside ing sho e ime pe iods? Thus, when ying o achie e a co ec PAP o PAPE s imulus du ing a wa m-up, he goal should be ocused on p ope ly combining a ce ain olume load (se s · epe i ions · kilog ams o pounds)1 wi h an app op ia e es in e al. To co ec ly achie e a po en ia ion e ec om a PAP o PAPE p o ocol, ec ui men o ype II ibe s is needed, and his can be done ei he using high in ensi ies22 o low in ensi ies close o muscle ailu e26. As ype II ibe s a e mo e sensi i e o calcium, a hle es wi h highe p opo ion o ype II ibe s will bene i mo e om high in ensi y (PAP o PAPE p o ocols whe e high o ces a e exe ed) p o ocols59. Conside ing ha ibe ype pe cen age is no ully inhe i ed139 and ha aining backg ound can ha e a huge impac on i 140, in e indi idual di e ences in esponse magni ude o he p o ocol a e common. In any case, p oximi y o ailu e (unde s ood as a leas an RPE 6 in he epe i ions in ese e based RPE scale54) is needed o ec ui ype II ibe s 128,141. As his in ensi y need can be ul illed in wo di e en ways, is he e any di e ence in a p o ocol based on in ensi y o based on olume? In he s udy by Lowe y e al. (2012)115 he medium load p o ocol (70% 1RM) imp o ed pe o mance 4 min pos condi ioning ac i i y (p < 0.05; ES = 1.46, la ge), while he high load p o ocol (93% 1RM) achie ed peak pe o mance 4 and 8 min pos condi ioning ac i i y (p < 0.05; ES4min = 1.34; ES8min = 1.48, la ge). These esul s a e suppo ed by Gilbe and Lees (2005)38, whe e inc eases in he isome ic RFD we e seen a wo di e en ime poin s o each g oup. The 1RM g oup (high in ensi y g oup) imp o ed 129 5.4.3 Isome ic PAPE and hea y li ing I isome ic con ac ions a e ene ge ically less demanding han sho ening con ac ions (i.e., a hypo he ic isome ic PAPE p o ocol should be ene ge ically less demanding han a adi ional high in ensi y dynamic PAPE p o ocol) and conside ing ha he s icking egion is he weakes poin o a li , pe o ming an isome ic PAPE p o ocol in he s icking egion is in e es ing. In his app oach, esea che s would be ying o acu ely imp o e pe o mance o he weakes poin o he li . Ne e heless, he e is some hing impo an o conside , he muscle leng h. I has been men ioned ea lie in “1.2.2.2 S icking Poin o S icking Region?” ha he s icking egion seems o be he poin whe e a clea mechanical disad an age occu s. This disad an age can be due o he a io be ween in e nal and ex e nal momen a ms o due o excessi e muscle leng h. Muscles a e o med by sa come es, and hese sa come es ha e hei leng h- o ce ela ionship, meaning ha hey ha e an op imum leng h whe e hey can apply o ce155 . When a sa come e (and by ex ension a muscle) is oo elonga ed (o oo sho ened) i s capaci y o apply ac i e o ce dec eases102,148. Thus, whene e he s icking egion o an indi idual is due o excessi e elonga ion o he in ol ed muscle, pe o ming isome ic con ac ions he e could no be help ul, bu expe imen al da a is lacking. Fo his eason, in ou s udy2 bench p ess g ip wid h was se a 1.4 imes biac omial dis ance, o ensu e ha he pec o alis majo no he iceps b achii we e no excessi ely elonga ed. In ha s udy2 we compa ed he e ec s o an isome ic (15 maximal isome ic con ac ions o 1 second wi h 1 second o es in be ween -15 MVIC-) PAPE p o ocol wi h a adi ional dynamic p o ocol (1 epe i ion wi h 93% 1RM) on mean p opulsi e eloci y and s icking egion kinema ics o a high loaded (85% 1RM) li . Mean p opulsi e eloci y did no 130 show signi ican imp o emen s bu s icking egion kinema ics did. The isome ic p o ocol imp o ed eloci y in he p e-s icking egion (p io o he ini ia ion o he s icking egion) (p < 0.001; ES = 0.67, mode a e e ec ; 95% CI [0.07, 0.02]), he 1s maximum eloci y peak (p =0.005; ES = 0.71, mode a e e ec ; 95% CI [0.02, 0.093]) and he minimum eloci y peak (p = 0.025; ES = 0.38, small e ec ; 95% CI [0.006, 0.072]). These esul s could seem o i ial impo ance, bu no hing is u he om eali y. Fo expe ienced li e s, a small change in mean p opulsi e eloci y can suppose he di e ence be ween succeeding a li o ailing i (wha was con i med by he smalles meaning ul di e ence calcula ion ca ied ou in ou s udy´s s a is ical analyses). Changes in he eloci y- ime p o ile o he li and he s icking egion kinema ics (i.e., less eloci y loss om maximum o minimum eloci y poin s) a e due o he g ea e impulse ha he li e has achie ed p io o he s icking egion. This augmen ed capaci y o apply o ce a e p esumably due o acu e s eng h adap a ions by he isome ic PAPE p o ocol, because as s a ed by Lum & Ba bosa (2019)4, isome ic s eng h aining enhances o ce om he adop ed join angles (in ou s udy2 he middle o he s icking egion) un il 20-50º away. This imp o emen o he i s pa o he li (p e-s icking egion) can p o ide he li e wi h enough impulse o a oid excessi e eloci y loss om Vmax peak o Vmin peak, u he ing pa icipan om ailu e. Un il his poin , i seems ha isome ic PAPE p o ocols applied in he S icking Region a e use ul o enhance sligh ly pe o mance ( educing epo ed RPEs), bu no enough o allow li ing mo e weigh . Sho ly, indings up o his poin sugges ha his p o ocol is help ul o aise success p obabili y in a hea y li , bu i does no imp o e maximal s eng h. Exe ed ac i e o ce is a esul o he numbe o c oss b idges o med in he high 131 o ce s a e156, and i all mo o uni s a e ec ui ed du ing a maximal s eng h ask128,141, p esumably he maximum quan i y o c oss b idges a e being o med. Thus, i should no be possible o imp o e he quan i y o o med c oss b idges wi hou c ea ing new sa come es, esul ing in an impossibili y o imp o e maximal s eng h acu ely. Wha can be done is imp o ing RFD pe c oss b idge. PAP and PAPE p o ocols imp o e RFD due o myosin ligh chain phospho yla ion, wha imp o es myosin´s mobili y and ge s myosin heads close o ac in binding si es63,157. The ole o PAP o PAPE in s eng h spo s migh be imp o ing pe o mance in submaximal loaded asks, such as pe o ming se s un il oli ional ailu e wi h 60-80% 1RM. As PAP o PAPE a e al eady commonly used o sp in ing107, jumping115 o h owing41, i seems easonable o hink ha i will be e ec i e in submaximally loaded s eng h asks. Following his line o easoning, K zysz o ik e al. (2020)50 and Al es e al. (2019)49 ound con lic ing esul s. K zysz o ik e al. (2020)50 ound no s a is ically signi ican di e ences in he numbe o pe o med epe i ions, bu hey ound an inc ease in ime unde ension o he PAPE g oup. Con a y o his, Al es e al. (2019)49 ound di e ences in he pe o med numbe o epe i ions in he i s and second se . The PAPE g oup pe o med mo e epe i ions (p < 0.05) (PAPE 11.5 ± 3.1 and 6.5 ± 1.9, in he i s and second se s espec i ely) han con ol g oup (10.4 ± 2.7, 5.5 ± 1.8, in he i s and second se s espec i ely). One key di e ence is he used load. While K zysz o ik e al. (2020)50 used 60% 1RM, Al es e al. (2019)49 used 75% 1RM. This could sugges ha when using excessi ely ligh loads, a igue could unde pin esul s26,130,141. Following Al es e al. (2019)49 esul s, we conduc ed a s udy using only one se un il oli ional ailu e wi h a highe in ensi y (80% 1RM) in he bench p ess, whe e we 132 compa ed a con ol g oup (no PAPE p o ocol) and a PAPE g oup ( he same wa m-up han in con ol g oup, bu wi h 1 se o 1 epe i ion a 93% 1RM p io o he ask o ailu e). Ou esul s suppo ed hose by Al es e al. (2019)49, bu also hose by, K zysz o ik e al. (2020)50. On one hand, pa icipan s in he PAPE g oup pe o med mo e epe i ions (10.83 ± 2.5 epe i ions) han in CON condi ion (9.76 ± 1.72 epe i ions) (p=0.008; ES=0.5, small e ec ). On he o he hand, mean p opulsi e eloci y o he las epe i ion p io o he concen ic oli ional ailu e was lowe in he PAPE condi ion (0.16 ± 0.06 m·s-1) han in he CON condi ion (0.2 ± 0.09 m·s-1) (p=0.02; ES=0.52, small e ec ), wha inc eases ime unde ension as in K zysz o ik e al. (2020)50. Al hough his imp o ed pe o mance in submaximal load asks is no di ec ly ele an o s eng h compe i o s, who need o maximal s eng h imp o emen s, i could be indi ec ly ele an . As muscle mass is he key de e minan o s eng h pe o mance in ad anced li e s58, imp o ing he hype ophic s imulus (i.e., imp o ed mechanical ension) ecei ed pe uni o aining bou (i.e., a aining se ) could be in e es ing in he long e m. To be s onge , hype ophy is needed a myo ib illa p o ein le el52, o impulse new sa come e c ea ion, e en hough any esis ance aining p og amme impulses p o ein c ea ion also a in acellula le el (e.g., ibosome biogenesis158) o ex acellula le el159. Depending on ained muscle leng h o con ac ion egime, sa come es will be added in pa allel o in se ies102,160, shi ing o ce-leng h ela ionship upwa ds102 o le wa ds101. In any case, he in e es ing aspec o using PAPE o muscle hype ophy aining is based on he augmen a ion o pe o med wo k. I PAPE imp o es pe o med numbe o epe i ions un il ailu e, olume load pe session (se s x epe i ions x kilog am)136 would imp o e, and so could muscle hype ophy. Following his line o easoning, i could also 133 be assumed ha hypo he ic muscle hype ophy bene i s could be due o bo h, imp o ed mechanical ension22,56 o he las epe i ion and o highe pe o med epe i ions136. In ou s udy3 pe o ming a adi ional PAPE p o ocol p io o oli ional ailu e made pa icipan s mo e a igue esis an , achie ing mo e epe i ions (9.76 ± 1.72 epe i ions he con ol g oup, s. 10.83 ± 2.5 epe i ions in he PAPE g oup). This pe o mance imp o emen s in a ask o oli ional ailu e in he bench p ess could be ela ed o an imp o ed capaci y o pe o m slowe epe i ions, as he PAPE g oup pe o med slowe he las epe i ion (0.2 ± 0.09 m·s-1 in he con ol g oup s. 0.16 ± 0.06 m·s-1 in he PAPE g oup). In consequence, he eloci y loss was g ea e om he i s o he las epe i ion and p e ious s udies suppo he no ion ha wi h a g ea e eloci y loss, muscle hype ophy gains can be g ea e 134. This means ha he pe o med ex a epe i ion may be e ec i e when aiming o p oduce muscle hype ophy, wha means ha he e icacy o e e y se would be highe (i.e., he achie ed hype ophy o e e y se would be highe ). 134 135 6 LIMITATIONS & FUTURE RESEARCH Look o wha is wi hin: do no allow he in insic quali y o he wo h o any one ac o escape you Ma cus Au elius – Medi a ions VI 3 136 137 6. LIMITATIONS & FUTURE RESEARCH 6.1 Limi a ions Ou wo k aced some limi a ions: • Ou i s o iginal esea ch aimed o measu e mean p opulsi e eloci y changes wi h a de ice ha was no sensi i e enough (e.g., eal magni ude changes we e abou 0.001 m·s-1 and he used de ice measu es 0.01m·s-1 o highe eloci ies). This di icul ed s a is ical analysis and esul in e p e a ion in mean p opulsi e eloci ies. Ne e heless, indi ec measu emen s using Kino ea based digi alisa ion allowed o ins an aneous eloci y compa isons, wha allowed o compa e esul s mo e p ecisely. • Ou second o iginal esea ch aced wi h sample size limi a ion, making di icul o gene alise achie ed esul s. Howe e , ob ained sample was o med by ained indi iduals, wha is ep esen a i e o he compe i i e popula ion. • In ou second o iginal esea ch we alk abou hypo he ic applica ions o PAPE o muscle mass gain, bu longi udinal da a is needed o i mly con i m ha hypo hesis. 6.2 Fu u e esea ch Fu u e wo k, based on wha has been p esen ed abo e could ocus on he ollowing: • A wide ange o a ailable p o ocols exis al eady. I would be in e es ing o es he di e en ime-po en ia ion p o iles o wo p o ocols ma ched in olume load 138 bu wi h di e en in ensi ies, o see i he ime-po en ia ion p o ile is he same in shape bu di e en in ime un il peak pe o mance. • Isome ic PAPE p o ocol applied in he middle o he s icking egion based on 15 MVIC wi h 1 second es in be ween has p o ed i s e icacy imp o ing li ing e iciency. I would be in e es ing o es he applica ion o he same p o ocol in la ge muscle leng hs, o es whe he i causes mo e a igue due o acu e muscle damage o imp o es pe o mance. • As PAPE p o ocols seem o imp o e pe o med wo k pe session, i would be in e es ing o design a s udy be ween 8 – 16 weeks o es i he po en ial bene i on hype ophy is eal o only hypo he ic. • PAP´s and PAPE´s unde lying mechanisms a e no mu ually exclusi e, as PAPE could be a side e ec o PAP o an ex ende PAP. The ole o empe a u e seems in e es ing bu emains o be p o en as a mechanism o PAPE. I would be wo h esea ching he eal ole o empe a u e in any PAPE p o ocol. 145 isomé icas son ene gé icamen e más exigen es que las con acciones excén icas, pe o écnicamen e más simples, los in e alos de descanso pod ían se ela i amen e simila es pa a ambos ipos de p o ocolos (es deci , 5-7 min pa a indi iduos más ue es y ≥8 min pa a indi iduos más débiles30). O o escena io en el que los p o ocolos de PAPE isomé icos son ú iles, es cuando los en enado es buscan mejo a el endimien o en le an amien os pesados con ca ga casi máxima. Como hemos demos ado en nues o es udio2, es posible que la elocidad media p opulsi a no mejo e signi ica i amen e, pe o sí lo hacen las elocidades máximas de la egión de es ancamien o, lo que acili a el le an amien o. Es a mejo a en los pun os cla e de la egión de es ancamien o (es deci , Vmax1 y Vmin) se log a con un p o ocolo de PAPE basado en con acciones isomé icas ealizadas en la zona de desacele ación164 de la egión de es ancamien o. El e ce y úl imo obje i o de es a esis ue p oba el impac o de un p o ocolo de PAPE en el olumen de en enamien o. En es e caso, el p o ocolo de PAPE p opues o e a un p o ocolo dinámico adicional1, ya que las se ies al allo concén ico se ealizan con ca ga submáxima. La e idencia en es a á ea es escasa y con adic o ia, pe o nues os esul ados espalda on los de Al es e al. (2019) 49, a i mando que un p o ocolo de PAPE puede mejo a el olumen de en enamien o de ue za. Es a mejo a puede debe se a azones psicológicas 47 o a azones de especi icidad de la elocidad de en enamien o 135. Como en enado que soy, al comenza es a esis, mi obje i o e a a a de comp ende mejo la b echa en e la ciencia y la p ác ica. Es a esis a a el ema de la PAPE en 146 di e en es (y ecuen es) si uaciones pa a un en enado de ue za, y po lo an o, me gus a ía esumi las conclusiones ex aídas: • Conclusión 1: Los en enado es deben comenza a di e encia PAP de PAPE y egión de es ancamien o de pun o de es ancamien o • Conclusión 2: Un p o ocolo de PAPE es un modelo de i ness- a iga agudo. Si el olumen es al o, la in ensidad debe se baja y ice e sa. Si el olumen y la in ensidad usados son al os, el uso de se ies clus e puede se ú il • Conclusión 3: Las pe sonas ue es se bene ician más de los p o ocolos pesados que las pe sonas no a as. Además, los indi iduos más ue es necesi an in e alos de descanso más co os (5-7 min) que sus compañe os más débiles (≥8 min) • Conclusión 4: Los p o ocolos de PAPE adicionales no son ú iles cuando se a a de mejo a el endimien o en le an amien os pesados. Sin emba go, los p o ocolos PAPE isomé icos son ú iles en es e escena io • Conclusión 5: Los p o ocolos de PAPE isomé icos no mejo an la ue za máxima, pe o mejo an la cinemá ica de la egión de es ancamien o, acili ando lige amen e el le an amien o y e i ando que el a le a alle • Conclusión 6: Un p o ocolo PAPE adicional de al a in ensidad puede mejo a el endimien o de una se ie lle ada al allo concén ico. Es o pod ía mejo a el olumen ealizado po sesión 147 8 REFERENCES Le no one delay in he s udy o philosophy while he is young, and when he is old, le him no become wea y o he s udy; o no man can e e ind he ime unsui able o oo la e o s udy he heal h o his soul Epicu us – Le e o Menoeceus 148 149 8. REFERENCES 1. Ga bisu-Hualde, A. & San os-Conceje o, J. Pos -Ac i a ion Po en ia ion in S eng h T aining: A Sys ema ic Re iew o he Scien i ic Li e a u e. J Hum Kine . 78, 141–150 (2021). 2. Ga bisu-Hualde, A., Gu ie ez, L., Fe nández-Peña, E. & San os-Conceje o, J. In e mi en Volun a y Isome ic Con ac ions E ec s on Pe o mance Enhancemen and S icking Region Kinema ics in he Bench P ess. J Hum Kine . 87, 105–117 (2023). 3. Ga bisu-Hualde, A., Gu ie ez, L. & San os-Conceje o, J. Pos -Ac i a ion Pe o mance Enhancemen as a S a egy o Imp o e Bench P ess Pe o mance o Voli ional Failu e. J Hum Kine . 88, Epub ahead o p in (2023). 4. Lum, D. & Ba bosa, T. M. B ie Re iew: E ec s o Isome ic S eng h T aining on S eng h and Dynamic Pe o mance. In e na ional Jou nal o Spo s Medicine 40, 363– 375 (2019). 5. Sku ydas, A. e al. Wha a e he bes isome ic exe cises o muscle po en ia ion? Eu J Appl Physiol 119, 1029-1039. (2019). 6. K zysz o ik, M. e al. Does Eccen ic-only and concen ic-only ac i a ion inc ease powe ou pu ? Med Sci Spo s Exe c 52, 484–489 (2020). 7. Gomo, O. & Tillaa , R. V. D. The e ec s o g ip wid h on s icking egion in bench p ess. J Spo s Sci. 34, 232–238 (2016). 8. Wes co , W. L. Resis ance aining is medicine: E ec s o s eng h aining on heal h. Cu en Spo s Medicine Repo s 11, 209–216 (2012). 9. Zi zmann, A. L. e al. The e ec o di e en aining equency on bone mine al densi y in olde adul s. A compa a i e sys ema ic e iew and me a-analysis. Bone 154, 1–13 (2022). 10. Lieg o, C. M. D., Schie a, G., P oia, P. & Lieg o, I. D. Physical ac i i y and b ain heal h. Genes 10, (2019). 11. Calle, M. C. & Fe nandez, M. L. E ec s o esis ance aining on he in lamma o y esponse. Nu i ion Resea ch and P ac ice 4, 259 (2010). 12. Se ano, A. L., Baeza-Raja, B., Pe digue o, E., Ja dí, M. & Muñoz-Cáno es, P. In e leukin-6 Is an Essen ial Regula o o Sa elli e Cell-Media ed Skele al Muscle Hype ophy. Cell Me abolism 7, 33–44 (2008). 150 13. Pede sen, B. K. & Febb aio, M. A. Muscle as an Endoc ine O gan: Focus on Muscle-De i ed In e leukin-6. Physiological e iews 88, 1379–1406 (2008). 14. McGowan, C. J., Pyne, D. B., Thompson, K. G. & Ra ay, B. Wa m-Up S a egies o Spo and Exe cise: Mechanisms and Applica ions. Spo s Med 45, 1523–1546 (2015). 15. Selye, H. A synd ome p oduced by di e se nocuous agen s. Na u e 1936, 32 (1936). 16. Cunanan, A. J. e al. The Gene al Adap a ion Synd ome: A Founda ion o he Concep o Pe iodiza ion. Spo s Medicine 48, 787–797 (2018). 17. Chiu, L. Z. F. & Ba nes, J. L. The Fi ness-Fa igue Model Re isi ed: Implica ions o Planning Sho - and Long-Te m T aining. S eng h and Condi ioning Jou nal 25, 42–51 (2003). 18. González-Badillo, J., Ma ques, M. & Sánchez-Medina, L. The Impo ance o Mo emen Veloci y as a Measu e o Con ol Resis ance T aining In ensi y. J Hum Kine 29A, 15–19 (2011). 19. Komp , J. & A andjelo ić, O. The S icking Poin in he Bench P ess, he Squa , and he Deadli : Simila i ies and Di e ences, and Thei Signi icance o Resea ch and P ac ice. Spo s Medicine 47, 631–640 (2017). 20. Komp , J. & A andjelo ić, O. Unde s anding and O e coming he S icking Poin in Resis ance Exe cise. Spo s Med. 46, 751–762 (2016). 21. Da ies, T., O , R., Halaki, M. & Hacke , D. E ec o T aining Leading o Repe i ion Failu e on Muscula S eng h: A Sys ema ic Re iew and Me a-Analysis. Spo s Medicine 46, 487–502 (2016). 22. Schoen eld, B. J. The Mechanisms o Muscle Hype ophy and Thei Applica ion o Resis ance T aining. J S eng h Cond Res 24, 2857–2872 (2010). 23. Schoen eld, B. J. & Con e as, B. The muscle pump: Po en ial mechanisms and applica ions o enhancing hype ophic adap a ions. S eng h and Condi ioning Jou nal 36, 21–25 (2014). 24. Nób ega, S. R. & Liba di, C. A. Is esis ance aining o muscula ailu e necessa y? F on ie s in Physiology 7, 75–78 (2016). 25. Viei a, J. G. e al. E ec s o Resis ance T aining o Muscle Failu e on Acu e Fa igue: A Sys ema ic Re iew and Me a-Analysis. Spo s Medicine 52, 1103–1125 (2022). 26. Dankel, S. J. e al. Do me aboli es ha a e p oduced du ing esis ance exe cise enhance muscle hype ophy? Eu J Appl Physiol. 117, 2125–2135 (2017). 151 27. Baz-Valle, E., Balsalob e-Fe nández, C., Alix-Fages, C. & San os-Conceje o, J. A Sys ema ic Re iew o he E ec s o Di e en Resis ance T aining Volumes on Muscle Hype ophy. J Hum Kine . 81, 199–210 (2022). 28. Baz-Valle, E., Fon es-Villalba, M. & San os-Conceje o, J. To al Numbe o Se s as a T aining Volume Quan i ica ion Me hod o Muscle Hype ophy. J S eng h Cond Res Publish Ahead o P in , NA; (2018). 29. MacIn osh, B. R., Robilla d, M. E. & Toma as, E. K. Should pos ac i a ion po en ia ion be he goal o you wa m-up? Appl Physiol Nu Me ab. 37, 546–550 (2012). 30. Co mie , P. e al. Wi hin Session Exe cise Sequencing du ing P og amming o Complex T aining : His o ical Pe spec i es , Te minology , and T aining Conside a ions. Spo s Medicine 1–38 (2022). 31. Sei z, L. B. & Ha , G. G. Fac o s Modula ing Pos -Ac i a ion Po en ia ion o Jump, Sp in , Th ow, and Uppe -Body Ballis ic Pe o mances: A Sys ema ic Re iew wi h Me a-Analysis. Spo s Medicine 46, 231–240 (2015). 32. Ca mo, E. C. do e al. Sel -Selec ed Res In e al Imp o es Ve ical Jump Pos - Ac i a ion Po en ia ion. Jou nal o S eng h and Condi ioning Resea ch 1 (2018) doi:10.1519/jsc.0000000000002519. 33. Lee, F. S. THE CAUSE OF THE TREPPE. Ame ican Jou nal o Physiology-Legacy Con en 18, 267–282 (1907). 34. Gu man, S. A., Ho on, R. G. & Wilbe , D. T. Enhancemen o muscle con ac ion a e e anus. Ame ican Jou nal o Physiology-Legacy Con en 119, 463–473 (1937). 35. Bu ke, R. E., Rudomin, P. & Zajac, F. E. The e ec o ac i a ion his o y on ension p oduc ion by indi idual muscle uni s. B ain Resea ch 109, 515–529 (1976). 36. Hacke , D. A. & Ami halingam, T. A b ie e iew o o ced epe i ions o he p omo ion o muscula hype ophy. S eng h and Condi ioning Jou nal 37, 14–20 (2015). 37. Tillin, N. A. & Bishop, D. Fac o s Modula ing Pos -Ac i a ion Po en ia ion and i s E ec on Pe o mance o Subsequen Explosi e Ac i i ies. Spo s Med 39, 147–166 (2009). 38. Gilbe , G. & Lees, A. Changes in he o ce de elopmen cha ac e is ics o muscle ollowing epea ed maximum o ce and powe exe cise. E gonomics 48, 1576–1584 (2005). 39. Gołas´, A. e al. Op imizing hal squa pos ac i a ion po en ial load in squa jump aining o elici ing ela i e maximal powe in ski jumpe s. Jou nal o S eng h and Condi ioning Resea ch 31, 3010–3017 (2017). 152 40. Kildu , L. P. e al. In luence o eco e y ime on pos -ac i a ion po en ia ion in p o essional ugby playe s. Jou nal o Spo s Sciences 26, 795–802 (2008). 41. K zysz o ik, M. e al. Pos ac i a ion Pe o mance Enhancemen o Concen ic Bench P ess Th ow A e Eccen ic-Only Condi ioning Exe cise. Jou nal o S eng h and Condi ioning Resea ch Epub ahead, (2020). 42. Lo is , M. M., Ke nell, D., Meijman, T. F. & Zijdewind, I. Mo o a igue and cogni i e ask pe o mance in humans. Jou nal o Physiology 545, 313–319 (2002). 43. Mussini, E. e al. E ec o ask complexi y on mo o and cogni i e p epa a o y b ain ac i i ies. In e na ional Jou nal o Psychophysiology 159, 11–16 (2021). 44. Lo u co, I. e al. The Op imum Powe Load: A Simple and Powe ul Tool o Tes ing and T aining. In e na ional Jou nal o Spo s Physiology and Pe o mance 17, 151–159 (2021). 45. O msbee, M. J. e al. E icacy O The Repe i ions In Rese e-Based Ra ing O Pe cei ed Exe ion Fo The Bench P ess In Expe ienced And No ice Benche s. Jou nal o S eng h and Condi ioning Resea ch 1 (2017) doi:10.1519/jsc.0000000000001901. 46. He nández-P eciado, J. A., Baz, E., Balsalob e-Fe nández, C., Ma chan e, D. & San os-Conceje o, J. Po en ia ion e ec s o he F ench con as me hod on e ical jumping abili y. Jou nal o S eng h and Condi ioning Resea ch 32, 1909–1914 (2018). 47. Szalma, J. L. & Hancock, P. A. Noise e ec s on human pe o mance: A me a- analy ic syn hesis. Psychological Bulle in 137, 682–707 (2011). 48. Woodman, T. e al. Emo ions and spo pe o mance: An explo a ion o happiness, hope, and ange . Jou nal o Spo and Exe cise Psychology 31, 169–188 (2009). 49. Al es, R. R. e al. Pos ac i a ion Po en ia ion Imp o es Pe o mance in a Resis ance T aining Session in T ained Men. J S eng h Cond Res. 35, 3296–3299 (2019). 50. K zysz o ik, M. e al. Can pos -ac i a ion pe o mance enhancemen (PAPE) imp o e esis ance aining olume du ing he bench p ess exe cise? In J En i on Res Public Heal h 17, (2020). 51. Ba aka , C., Pea son, J., Escalan e, G., Campbell, B. & Souza, E. O. D. Body Recomposi ion: Can T ained Indi iduals Build Muscle and Lose Fa a he Same Time? S eng h & Condi ioning Jou nal 42, 7–21 (2020). 52. Haun, C. T. e al. A c i ical e alua ion o he biological cons uc skele al muscle hype ophy: Size ma e s bu so does he measu emen . F on ie s in Physiology 10, 1– 23 (2019). 53. Folland, J. P. & Williams, A. G. The adap a ions o s eng h aining: Mo phological and neu ological con ibu ions o inc eased s eng h. Spo s Medicine 37, 145–168 (2007). 153 54. Helms, E. R., C onin, J., S o ey, A. & Zou dos, M. C. Applica ion o he Repe i ions in Rese e-Based Ra ing o Pe cei ed Exe ion Scale o Resis ance T aining. S eng h and Condi ioning Jou nal 38, 42–49 (2016). 55. Sun, Z., Guo, S. S. & Fässle , R. In eg in-media ed mechano ansduc ion. J Cell Biol 215, 445–456 (2016). 56. Alix-Fages, C., Vecchio, A. D., Baz-Valle, E., San os-Conceje o, J. & Balsalob e- Fe nández, C. The ole o he neu al s imulus in egula ing skele al muscle hype ophy. Eu opean Jou nal o Applied Physiology (2022) doi:10.1007/s00421-022-04906-6. 57. Ma ino, F., Pe es elo, A. R., Vina ský, V., Paglia i, S. & Fo e, G. Cellula mechano ansduc ion: F om ension o unc ion. F on Physiol. 9, 1–21 (2018). 58. Maden-Wilkinson, T. M., Balshaw, T. G., Massey, G. J. & Folland, J. P. Wha makes long- e m esis ance- ained indi iduals so s ong? A compa ison o skele al muscle mo phology, a chi ec u e, and join mechanics. Jou nal o Applied Physiology 128, 1000–1011 (2020). 59. Blaze ich, A. J. & Babaul , N. Pos -ac i a ion Po en ia ion Ve sus Pos -ac i a ion Pe o mance Enhancemen in Humans: His o ical Pe spec i e, Unde lying Mechanisms, and Cu en Issues. F on ie s in Physiology 10, (2019). 60. Hodgson, M., Doche y, D. & Robbins, D. Pos -ac i a ion po en ia ion: Unde lying physiology and implica ions o mo o pe o mance. Spo s Medicine 35, 585–595 (2005). 61. Hall, J. & Guy on, A. C. Guy on and Hall Tex book o Medical Physiology - 13 h Edi ion. (Saunde s, 2015). 62. Robe is, E. D. & Hib, J. Fundamen os de Biología celula y molecula de De Robe is. (2004). 63. G ange, R. W., Vandenboom, R. & Hous on, M. E. Physiological Signi icance o Myosin Phospho yla ion in Skele al Muscle. Canadian Jou nal o Applied Physiology 18, 229–242 (2008). 64. Jones, M. e al. Phospho yla ion o he egula o y ligh chains o myosin a ec s Ca 2+ sensi i i y o skele al muscle con ac ion . Jou nal o Applied Physiology 92, 1661– 1670 (2015). 65. Wilson, J. M. e al. Me a-Analysis o Pos ac i a ion Po en ia ion and Powe . J S eng h Cond Res 27, 854–859 (2013). 66. K u ki, P., M ówczyński, W., Baczyk, M., Łochyński, D. & Celichowski, J. Adap a ions o mo oneu on p ope ies a e weigh -li ing aining in a s. Jou nal o Applied Physiology 123, 664–673 (2017). 154 67. Nuzzo, J. L., Ba y, B. K., Gande ia, S. C. & Taylo , J. L. Acu e s eng h aining inc eases esponses o s imula ion o co icospinal axons. Medicine and Science in Spo s and Exe cise 48, 139–150 (2016). 68. Squi e, L. R. e al. Fundamen al Neu oscience. (Else ie Inc., 2013). doi:10.1016/b978-0-12-385870-2.00047-0. 69. M ówczyński, W., Celichowski, J., Raiko a, R. & K u ki, P. Physiological consequences o double discha ges on mo oneu onal i ing and mo o uni o ce. F on ie s in Cellula Neu oscience 9, 1–6 (2015). 70. Lep oul , R. & Pe sson, P. B. Enhanced men al pe o mance a highe body empe a u e? Ame ican Jou nal o Physiology - Regula o y In eg a i e and Compa a i e Physiology 283, 8–9 (2002). 71. Sugi, H. e al. Enhancemen o Fo ce Gene a ed by Indi idual Myosin Heads in Skinned Rabbi Psoas Muscle Fibe s a Low Ionic S eng h. PLoS ONE 8, 1–8 (2013). 72. Sugi, H. e al. Elec on mic oscopic eco ding o myosin head powe s oke in hyd a ed myosin ilamen s. Scien i ic Repo s 5, 1–11 (2015). 73. Decos e, V., Bianco, P., Lomba di, V. & Piazzesi, G. E ec o empe a u e on he wo king s oke o muscle myosin. P oceedings o he Na ional Academy o Sciences o he Uni ed S a es o Ame ica 102, 13927–13932 (2005). 74. Rod igues, P., T ajano, G. S., S ewa , I. B. & Mine , G. M. Po en ial ole o passi ely inc eased muscle empe a u e on con ac ile unc ion. Eu J Appl Physiol. (2022) doi:10.1007/s00421-022-04991-7. 75. Racinais, S., Wilson, M. G. & Pé ia d, J. D. Passi e hea acclima ion imp o es skele al muscle con ac ili y in humans. Am J Physiol Regul In eg Comp Physiol 312, 101–107 (2017). 76. Go o, K. e al. Responses o muscle mass, s eng h and gene ansc ip s o long- e m hea s ess in heal hy human subjec s. Eu opean Jou nal o Applied Physiology 111, 17–27 (2011). 77. Ahmadizad, S. & El-Sayed, M. S. The acu e e ec s o esis ance exe cise on he main de e minan s o blood heology. Jou nal o Spo s Sciences 23, 243–249 (2005). 78. Nade , E. e al. Blood heology: Key pa ame e s, impac on blood low, ole in sickle cell disease and e ec s o exe cise. F on ie s in Physiology 10, (2019). 79. Eng, C. M., Azizi, E. & Robe s, T. J. S uc u al de e minan s o muscle gea ing du ing dynamic con ac ions. In eg a i e and Compa a i e Biology 58, 207–218 (2018). 80. Eng, C. M. & Robe s, T. J. Aponeu osis in luences he ela ionship be ween muscle gea ing and o ce. J Appl Physiol 125, 513–519 (2018).