Associations of fat mass and fat-free mass with physical fitness in 4-year-old children: Results from the MINISTOP trial

This is an elec onic ep in o he o iginal a icle. This ep in may di e om he o iginal in pagina ion and ypog aphic de ail. Au ho (s): Ti le: Yea : Ve sion: Please ci e he o iginal e sion: All ma e ial supplied ia JYX is p o ec ed by copy igh and o he in ellec ual p ope y igh s, and duplica ion o sale o all o pa o any o he eposi o y collec ions is no pe mi ed, excep ha ma e ial may be duplica ed by you o you esea ch use o educa ional pu poses in elec onic o p in o m. You mus ob ain pe mission o any o he use. Elec onic o p in copies may no be o e ed, whe he o sale o o he wise o anyone who is no an au ho ised use . Associa ions o a mass and a - ee mass wi h physical i ness in 4-yea -old child en: Resul s om he MINISTOP ial Hen iksson, Pon us; Cadenas-Sanchez, C is ina; Leppänen, Ma ja; Nys öm, Ch is ine Delisle; O ega, F ancisco B.; Pome oy, Je emy; Ruiz, Jona an R.; Lö , Ma ie Hen iksson, P., Cadenas-Sanchez, C., Leppänen, M., Nys öm, C. D., O ega, F. B., Pome oy, J., Ruiz, J. R., & Lö , M. (2016). Associa ions o a mass and a - ee mass wi h physical i ness in 4-yea -old child en: Resul s om he MINISTOP ial. Nu ien s, 8(8), A icle 473. h ps://doi.o g/10.3390/nu8080473 2016 nu ien s A icle Associa ions o Fa Mass and Fa -F ee Mass wi h Physical Fi ness in 4-Yea -Old Child en: Resul s om he MINISTOP T ial Pon us Hen iksson 1,2,*, C is ina Cadenas-Sanchez 1, Ma ja H. Leppänen 3, Ch is ine Delisle Nys öm 4, F ancisco B. O ega 1,4, Je emy Pome oy 5, Jona an R. Ruiz 1,4 and Ma ie Lö 2,4,* 1PROmo ing FITness and Heal h h ough Physical Ac i i y Resea ch G oup (PROFITH), Depa men o Physical Educa ion and Spo , Facul y o Spo Sciences, Uni e si y o G anada, 18071 G anada, Spain; [email p o ec ed] (C.C.-S.); o ega @ug .es (F.B.O.); uizj@ug .es (J.R.R.) 2Depa men o Clinical and Expe imen al Medicine, Facul y o Heal h Science, Linköping Uni e si y, 581 53 Linköping, Sweden 3Depa men o Heal h Sciences, Uni e si y o Jy askyla, 40014 Jy askyla, Finland; [email p o ec ed] 4Depa men o Biosciences and Nu i ion, Ka olinska Ins i u e , 141 83 Huddinge, Sweden; [email p o ec ed] 5Ma sh ield Clinic Resea ch Founda ion, Ma sh ield, WI 54449, USA; pome oy[email p o ec ed] *Co espondence: [email p o ec ed] (P.H.); [email p o ec ed] (M.L.); Tel.: +34-620-768-977 (P.H.); +46-852-481-095 (M.L.) Recei ed: 16 June 2016; Accep ed: 27 July 2016; Published: 30 July 2016 Abs ac : Physical i ness is a powe ul ma ke o heal h in you h. S udies in adolescen s and adul s sugges ha highe a mass is ela ed o wo se physical i ness. Howe e , he e is limi ed knowledge whe he a mass and a - ee mass a e associa ed wi h physical i ness al eady in p eschoole s. Baseline da a om he MINISTOP (Mobile-based IN e en ion In ended o STop Obesi y in P eschoole s) ial was u ilized o his c oss-sec ional analysis. Body composi ion was assessed using ai -displacemen ple hysmog aphy. Fa mass index [ a mass (kg)/heigh 2 (m)] and a - ee mass index [ a - ee mass (kg)/heigh 2 (m)] we e used o p o ide heigh -adjus ed measu es o body composi ion. Physical i ness was measu ed using he PREFIT (FITness es ing in PREschool child en) ba e y, which assesses ca dio espi a o y i ness, uppe -body and lowe -body muscula s eng h as well as mo o i ness. In o al, his s udy included 303 child en (168 boys and 135 gi ls), who we e on a e age 4.48 ˘ 0.15 yea s old. Highe a mass index was associa ed wi h wo se ca dio espi a o y i ness (s anda dized β = ´ 0.17, p= 0.002), lowe -body muscula s eng h ( β=´0.17 ,p= 0.003) and mo o i ness ( β = ´ 0.21, p< 0.001) in eg ession analyses adjus ed o age, sex and mu ually adjus ed o a -mass index and a - ee mass index. Con e sely, highe a - ee mass index was associa ed wi h be e ca dio espi a o y i ness ( β = 0.18, p= 0.002), uppe -body muscula s eng h ( β = 0.39, p< 0.001 ), lowe -body muscula s eng h ( β = 0.22, p< 0.001) and mo o i ness ( β = 0.17, p= 0.004). Thus, a mass and a - ee mass in p eschoole s appea o ha e join bu opposi e associa ions wi h physical i ness, an impo an ma ke o cu en and u u e heal h. Keywo ds: ai -displacemen ple hysmog aphy; body composi ion; ca dio espi a o y i ness; muscula s eng h; mo o i ness; p eschool 1. In oduc ion Childhood obesi y is a se ious public heal h challenge [1] and he p opo ion o o e weigh and obese child en is high in many coun ies [ 1 , 2 ]. This is o g ea conce n since childhood obesi y is associa ed wi h a highe isk o adul obesi y [ 1 , 3 ] as well as impai ed heal h [ 4 ] la e in li e. A high Nu ien s 2016,8, 473; doi:10.3390/nu8080473 www.mdpi.com/jou nal/nu ien s Nu ien s 2016,8, 473 2 o 11 body a ness in childhood may also ha e a nega i e impac on physical i ness [ 5 – 8 ], which is a po en ially impo an obse a ion since physical i ness is a powe ul ma ke o heal h al eady in you h [ 4 , 9 , 10 ]. Fo ins ance, highe le els o physical i ness (pa icula ly ca dio espi a o y i ness and muscula s eng h) in childhood and adolescence ha e been associa ed wi h a heal hie ca dio ascula p o ile la e in li e and wi h a lowe isk o p ema u e dea h [ 4 , 9 , 10 ]. Al hough he e is some e idence ha body a ness may be ela ed o physical i ness in p ima y school child en [ 5 , 7 , 8 ], e y li le is known whe he such associa ions a e p esen al eady in p eschool child en, i.e., child en aged 5 yea s o younge . The ew s udies conduc ed in p eschoole s sugges ha a highe body mass index (BMI) is associa ed wi h a lowe ca dio espi a o y i ness [ 11 – 15 ] bu wi h a highe uppe -body muscula s eng h [ 12 , 16 ]. Fu he , con lic ing esul s ha e been p esen ed whe he BMI is associa ed wi h lowe -body muscula s eng h and measu es o mo o i ness/speed-agili y [ 12 , 13 , 15 – 17 ]. Howe e , BMI is poo ly co ela ed wi h % a mass (%FM) in a p eschool popula ion [ 18 ]. Fu he mo e, BMI e lec s bo h he a mass (FM) and he a - ee mass (FFM) in he body [ 19 ], which may ha e di e en associa ions wi h physical i ness. To ou knowledge, only wo s udies [ 14 , 15 ] ha e epo ed any da a on he associa ion be ween es ima es o FM wi h physical i ness in p eschoole s. Fu he mo e, we ha e no ound any s udies ha ha e in es iga ed associa ions be ween FFM and physical i ness in p eschoole s. Consequen ly, u he s udies in es iga ing associa ions o bo h FM and FFM wi h physical i ness a e wa an ed in p eschoole s. The aim o his s udy was he e o e o in es iga e he associa ions o FM and FFM wi h physical i ness in p eschool-aged child en. 2. Ma e ials and Me hods 2.1. Design and Pa icipan s This s udy was pe o med unde he umb ella o he MINISTOP p ojec (Mobile-based IN e en ion In ended o STop Obesi y in P eschoole s) [ 20 , 21 ]. B ie ly, he MINISTOP p ojec is a andomized con olled ial conduc ed in Ös e gö land (Sweden) be ween 2014 and 2015. The objec i e was o e alua e he impac o a mobile-based pa en al heal h in e en ion on body a ness, die a y habi s, physical i ness, physical ac i i y and seden a y beha iou in 4-yea -old child en [ 20 ]. This analysis only includes baseline da a collec ed p io o andomiza ion. O he 315 p eschoole s assessed a baseline, 303 had comple e body composi ion da a and we e included in his s udy. Pa en s epo ed hei age, weigh , heigh and educa ional a ainmen using a ques ionnai e. The s udy was conduc ed acco ding o he guidelines laid down in he Decla a ion o Helsinki and in o med consen , wi nessed and o mally eco ded, was ob ained om all pa en s. The MINISTOP ial was app o ed by he Resea ch E hics Commi ee, S ockholm, Sweden (2013/1607–31/5; 2013/2250–32) and is egis e ed as a clinical ial (h ps://clinical ials.go /c 2/show/NCT02021786). 2.2. Body Composi ion Weigh was measu ed o he nea es g am using an elec onic scale a ached o he BodPod (COSMED USA, Conco d, CA, USA). Heigh was measu ed using a wall s adiome e (Tillquis , Spånga, Sweden) o he nea es 0.1 cm. O e weigh /obesi y was classi ied acco ding o Cole e al. [ 22 ]. Weigh - o -age and leng h- o -age z-sco es we e calcula ed using Swedish e e ence da a [ 23 ]. FM and FFM we e assessed using ai -displacemen ple hysmog aphy using he pedia ic op ion o BodPod (COSMED USA, Conco d, CA, USA), which has been shown o be accu a e in he es ima ion o %FM in p eschool child en [ 24 ]. The comple e es -p ocedu e has been desc ibed elsewhe e [ 18 , 24 ]. All measu emen s we e pe o med wi hou shoes and in igh i ing unde wea . BMI was calcula ed as body weigh (kg)/heigh 2 (m). Fa mass index (FMI) [FM (kg)/heigh 2 (m)] and a - ee mass index (FFMI) [ a - ee mass (kg)/heigh 2 (m)] we e calcula ed o p o ide heigh -adjus ed measu es o FM and FFM, espec i ely. Nu ien s 2016,8, 473 3 o 11 2.3. Physical Fi ness Ca dio espi a o y i ness, muscula s eng h and mo o i ness we e assessed by he PREFIT (FITness es ing in PREschool child en) ba e y [ 25 ]. De ailed in o ma ion o each es has been epo ed elsewhe e [ 26 ]. Ca dio espi a o y i ness was measu ed using he 20 m shu le un es which s a ed a 8.5 km/h and inc eased 0.5 km/h/min. Each child an he 20 m shu le un es indi idually and one pe son om he ained esea ch s a an nex o he child in o de o pace hem. Uppe -body muscula s eng h was assessed by he handg ip s eng h es using an analogue dynamome e (TKK 5001, G ip-A, Takei, Tokyo, Japan) wi h a g ip span o 4.5 cm. Fo lowe -body muscula s eng h, he s anding long jump es was used. Mo o i ness and speed-agili y was assessed by he 4 ˆ 10 m shu le un es . All i ness es s we e conduc ed wice, apa om he 20 m shu le un es ha was pe o med once. In he handg ip s eng h es , he bes o wo a emp s o each hand was selec ed, and he a e age o bo h hands was calcula ed and used in he analyses. Fo he s anding long jump and he 4 ˆ10 m shu le un es s, he bes o wo a emp s was used. 2.4. Physical Ac i i y As desc ibed p e iously [ 21 ], he child en wo e he Ac iG aph wGT3x-BT iaxial accele ome e (www.ac ig aphco p.com) on he non-dominan w is o 24 h du ing se en consecu i e days. A alid day was ě 600 min o awake wea ing ime [ 27 ] and child en wi h ě 3 days o alid da a we e used in he analyses. Time in igo ous-in ensi y physical ac i i y (VPA) was calcula ed om he sum o ec o magni udes using a cu -poin o ě1969 ec o magni ude pe 5 s [28]. 2.5. S a is ical Analysis To in es iga e associa ions be ween body composi ion (x) and physical i ness (y), linea eg ession analyses we e conduc ed. Th ee eg ession models we e c ea ed: (1) unadjus ed model; (2) model adjus ed o age and sex o he child, and models wi h FMI and FFMI as independen a iables we e also mu ually adjus ed o FMI and FFMI; and (3) model adjus ed o he po en ial con ounde s desc ibed in model 2 plus he amoun o ime spen in VPA (min/day) since VPA has p e iously been associa ed wi h physical i ness in p eschoole s [ 21 , 29 ]. Fu he adjus men s o all eg ession models o ma e nal and pa e nal a iables (age, BMI, educa ional a ainmen ) had e y li le in luence on he es ima es. We u he examined sex-in e ac ions be ween body composi ion and sex by including in e ac ion e ms (i.e., body composi ion measu e ˆ sex) sepa a ely in he eg ession models. pwas >0.05 o all in e ac ion e ms and consequen ly, we p esen he esul s o boys and gi ls oge he . Independen - es s o chi squa e es s we e applied o es di e ences be ween g oups. All hypo hesis es s we e wo-sided and a p< 0.05 was conside ed s a is ically signi ican . S a is ical analysis was pe o med using SPSS S a is ics 22 (IBM, A monk, NY, USA). 3. Resul s 3.1. Desc ip i e S a is ics Mo he s o he child en in he s udy we e on a e age 36 ˘ 4 (mean ˘ SD) yea s old, had an a e age BMI o 24.1 ˘ 4.8 kg/m 2 , and 71% o mo he s had a uni e si y deg ee. Fa he s we e on a e age 38 ˘ 5 yea s old, had an a e age BMI o 25.2 ˘ 4.3 kg/m 2 , and 58% had a uni e si y deg ee. Table 1 p esen s he age, an h opome ic a iables, body composi ion and physical i ness o he 303 child en. Nu ien s 2016,8, 473 4 o 11 Table 1. Desc ip i e cha ac e is ics o he p eschool child en. All Boys Gi ls pa nValue nValue nValue Age (yea s) 303 4.48 ˘0.15 168 4.49 ˘0.15 135 4.47 ˘0.15 0.34 Weigh (kg) 303 18.3 ˘2.5 168 18.5 ˘2.4 135 18.1 ˘2.6 0.11 Weigh o age z-sco e b303 ´0.07 ˘1.11 168 ´0.07 ˘1.11 135 ´0.07 ˘1.10 0.97 Heigh (cm) 303 107.6 ˘4.2 168 107.9 ˘4.3 135 107.1 ˘4.1 0.10 Heigh o age z-sco e b303 ´0.04 ˘0.97 168 ´0.03 ˘1.00 135 ´0.05 ˘0.94 0.85 P opo ion o o e weigh /obesi y c303 26 (8.6%) 168 14 (8.3%) 135 12 (8.9%) 0.86 BMI (kg/m2)303 15.8 ˘1.4 168 15.8 ˘1.3 135 15.7 ˘1.4 0.28 FMI (kg/m2)303 4.1 ˘0.9 168 4.0 ˘0.8 135 4.3 ˘1.0 0.001 FFMI (kg/m2)303 11.6 ˘1.0 168 11.9 ˘1.0 135 11.4 ˘0.9 <0.001 FM (%) 303 26.0 ˘4.4 168 25.0 ˘3.9 135 27.3 ˘4.7 <0.001 Physical i ness es cha ac e is ics 20 m shu le un (laps) 296 5.9 ˘2.6 162 5.7 ˘2.6 134 6.1 ˘2.6 0.20 Handg ip s eng h (kg) 302 6.4 ˘1.6 168 6.8 ˘1.6 134 6.0 ˘1.4 <0.001 S anding long jump (cm) 303 71.7 ˘15.2 168 72.3 ˘15.6 134 70.9 ˘14.6 0.43 4ˆ10 m shu le un d(s) 303 18.2 ˘1.9 168 18.2 ˘2.2 134 18.0 ˘1.6 0.34 Ac iG aph cha ac e is ics Valid days e295 6.7 ˘0.8 166 6.7 ˘0.7 129 6.6 ˘1.0 0.089 Awake wea ing ime (min/day) 295 841 ˘56 166 840 ˘59 129 843 ˘53 0.67 VPA (min/day) 295 7.4 ˘4.9 166 8.1 ˘5.6 129 6.5 ˘3.6 0.004 Da a a e means ˘ s anda d de ia ion o n(%). BMI, body mass index; FM, a mass; FFMI, a - ee mass index; FMI, a -mass index; VPA, igo ous-in ensi y physical ac i i y. a Re e s o he p alue o an independen es (con inuous a iables) o chi squa e es (ca ego ical a iables) be ween boys and gi ls; b Calcula ed using Swedish e e ence da a [ 23 ]; c Classi ied acco ding he Wo ld Obesi y ede a ion [ 22 ] cu -o ; d In his es , lowe sco es (in seconds) indica e highe pe o mance; e De ined as ě 600 min o nonsleeping da a [ 27 ]; Classi ied acco ding o Chandle e al. [28]. 3.2. Associa ions o Body Composi ion wi h Physical Fi ness Table 2 epo s he associa ions be ween body composi ion (x) and physical i ness (y). BMI was posi i ely associa ed wi h handg ip s eng h (p< 0.001) bu had no s a is ically signi ican associa ions wi h any o he physical i ness a iables. In adjus ed analysis, each uni (kg/m 2 ) inc ease in BMI was associa ed wi h a 0.38 kg (p< 0.001) inc ease in he handg ip s eng h es . Fu he adjus men s o VPA had li le in luence on he associa ions o BMI wi h physical i ness. Using body weigh ins ead o BMI yielded e y simila esul s in he analyses. Thus, body weigh (kg) was associa ed wi h handg ip s eng h (kg) in he adjus ed model (b = 0.32, s anda dized β= 0.50, p< 0.001) bu no wi h any o he physical i ness measu es (p> 0.05). Finally, esul s we e also compa able when compa ing non-o e weigh and o e weigh child en (Table S1). Thus, o e weigh child en had a highe a e age handg ip s eng h as compa ed o non-o e weigh child en (7.5 kg s. 6.3 kg, p< 0.001), bu no o he s a is ically signi ican di e ences we e obse ed. FMI and %FM we e associa ed wi h a wo se pe o mance in he 20 m shu le un, s anding long jump and 4 ˆ 10 m shu le un es s. Mo e speci ically, in adjus ed analyses, each uni (kg/m 2 ) inc ease in FMI was associa ed wi h a wo se pe o mance in he 20 m shu le un ( ´ 0.50 laps, p= 0.002 ), s anding long jump ( ´ 2.8 cm, p= 0.003) and 4 ˆ 10 m shu le un (+0.45 s, p< 0.001) es s. Simila ly, %FM in adjus ed analyses was associa ed wi h a wo se pe o mance o he 20 m shu le un, s anding long jump, and 4 ˆ 10 m shu le un es s (p ď 0.001). Fu he adjus men o VPA had e y li le in luence on he obse ed associa ions be ween FMI and %FM and physical i ness. FFMI was associa ed wi h all measu es o physical i ness. In adjus ed analyses, each uni (kg/m 2 ) inc ease in he FFMI was associa ed wi h a be e pe o mance in he 20 m shu le un (+0.48 laps, p= 0.002 ), handg ip s eng h (+0.64 kg, p< 0.001), s anding long jump (+3.4 cm, p< 0.001) and 4ˆ10 m shu le un ( ´ 0.33 s, p= 0.004) es s. A e adjus ing hese models o VPA, he obse ed associa ions be ween FFMI and physical i ness we e sligh ly a enua ed; howe e , hey emained s a is ically signi ican (all pď0.043). Nu ien s 2016,8, 473 5 o 11 Table 2. Associa ions o Body Composi ion wi h Physical Fi ness a. Body Composi ion Measu es (x) BMI (kg/m2) FMI (kg/m2) FFMI (kg/m2)FM (%) Physical i ness es s (y) b SE pb SE pb SE pb SE p 20 m shu le un (laps) Unadjus ed 0.01 0.11 0.92 ´0.46 0.16 0.006 0.44 0.16 0.006 ´0.12 0.03 <0.001 Adjus ed b0.01 0.11 0.95 ´0.50 0.16 0.002 0.48 0.16 0.002 ´0.12 0.03 <0.001 Adjus ed b+ VPA ´0.05 0.10 0.61 ´0.45 0.15 0.003 0.33 0.15 0.030 ´0.11 0.03 0.001 Handg ip s eng h (kg) Unadjus ed 0.40 0.06 <0.001 0.07 0.10 0.50 0.72 0.09 <0.001 ´0.04 0.02 0.070 Adjus ed b0.38 0.06 <0.001 0.10 0.09 0.26 0.64 0.09 <0.001 ´0.01 0.02 0.64 Adjus ed b+ VPA 0.37 0.06 <0.001 0.11 0.09 0.24 0.61 0.09 <0.001 ´0.01 0.02 0.79 S anding long jump (cm) Unadjus ed 0.43 0.64 0.50 ´2.66 0.94 0.005 3.30 0.88 <0.001 ´0.74 0.19 <0.001 Adjus ed b0.36 0.64 0.57 ´2.77 0.94 0.003 3.38 0.91 <0.001 ´0.69 0.20 0.001 Adjus ed b+ VPA 0.09 0.64 0.88 ´2.71 0.94 0.004 2.85 0.92 0.002 ´0.65 0.20 0.001 4ˆ10 m shu le un c(s) Unadjus ed 0.05 0.08 0.55 0.41 0.12 0.001 ´0.28 0.11 0.015 0.10 0.03 <0.001 Adjus ed b0.05 0.08 0.53 0.45 0.12 <0.001 ´0.33 0.12 0.004 0.10 0.03 <0.001 Adjus ed b+ VPA 0.09 0.08 0.27 0.41 0.12 <0.001 ´0.23 0.11 0.043 0.09 0.02 <0.001 BMI, body mass index; FM, a mass; FFMI, a - ee mas index; FMI, a -mass index; VPA, igo ous-in ensi y physical ac i i y; x, independen a iables; y, dependen a iables. a Analysed using eg ession analysis. The uns anda dized eg ession coe icien ( b ) wi h i s s anda d e o (SE) and he p alue (p) a e gi en o each associa ion; b All models we e adjus ed o child ´ s sex and age. Models wi h FMI as he independen a iable we e u he adjus ed o FFMI while models wi h FFMI as he independen a iable we e u he adjus ed o FMI; c In his es , lowe sco es (in seconds) indica e highe pe o mance. Hence, highe FFMI and lowe FMI we e associa ed wi h highe pe o mance in he 4 ˆ 10 m shu le un es . Nu ien s 2016,8, 473 6 o 11 We u he explo ed associa ions o FMI and FFMI wi h physical i ness by isual ep esen a ion o he s anda dized β -coe icien s om he adjus ed models, i.e., he change in physical i ness (in SD) ha is associa ed wi h a 1-SD inc ease in FMI and FFMI (Figu e 1). Thus, FMI ( β = ´ 0.17 o ´ 0.21) and FFMI ( β = 0.17–0.22) appea o ha e join bu opposi e associa ions wi h physical i ness in he weigh -bea ing i ness es (i.e., shu le uns and s anding long jump). Please no e ha he slopes o he 4 ˆ 10 m shu le un we e in e ed since a lowe sco e in his es (in seconds) indica es highe pe o mance. Fu he mo e, FFMI had a s ong in luence (β= 0.39) on handg ip s eng h. Nu ien s 2016,8,4736o 11  Figu e1.G aphical ep esen a iono  hes anda dized eg essioncoe icien s(β) o  heassocia ions o  a massindex(FMI;solidlines)and a ‐ eemassindex(FFMI;dashedlines)wi hmeasu eso  physical i ness.Thes anda dized eg essioncoe icien s e e  o hechangeinphysical i ness(inSD) ha a eassocia edwi ha1‐SDinc easeinFMIandFFMI.Reg essionmodelswe eadjus ed o age andsexandmu uallyadjus ed o FMIandFFMI.Pleaseno e ha  heo iginal4×10mshu le un a iablewasin e ed(− o+and ice e sa)be o ebeing ep esen edin his igu e.Thus, his es can nowbein e p e edsimila  o he emainde o  hephysical i ness es s,i.e.,ahighe sco eindica es be e pe o mance. We u he explo edassocia ionso FMIandFFMIwi hphysical i nessby isual ep esen a ion o  hes anda dizedβ‐coe icien s om headjus edmodels,i.e., hechangeinphysical i ness(inSD) ha isassocia edwi ha1‐SDinc easeinFMIandFFMI(Figu e1).Thus,FMI(β=−0.17 o−0.21)and FFMI(β=0.17–0.22)appea  oha ejoin bu opposi eassocia ionswi hphysical i nessin heweigh ‐ bea ing i ness es (i.e.,shu le unsands andinglongjump).Pleaseno e ha  heslopes o  he4× 10mshu le unwe ein e edsincealowe sco ein his es (inseconds)indica eshighe  pe o mance.Fu he mo e,FFMIhadas ongin luence(β=0.39)onhandg ips eng h.   Figu e 1. G aphical ep esen a ion o he s anda dized eg ession coe icien s ( β ) o he associa ions o a mass index (FMI; solid lines) and a - ee mass index (FFMI; dashed lines) wi h measu es o physical i ness. The s anda dized eg ession coe icien s e e o he change in physical i ness (in SD) ha a e associa ed wi h a 1-SD inc ease in FMI and FFMI. Reg ession models we e adjus ed o age and sex and mu ually adjus ed o FMI and FFMI. Please no e ha he o iginal 4 ˆ 10 m shu le un a iable was in e ed ( ´ o + and ice e sa) be o e being ep esen ed in his igu e. Thus, his es can now be in e p e ed simila o he emainde o he physical i ness es s, i.e., a highe sco e indica es be e pe o mance. Nu ien s 2016,8, 473 7 o 11 4. Discussion 4.1. S a emen o P incipal Findings We obse ed ha a highe FMI was associa ed wi h wo se physical i ness in all weigh -bea ing es s (i.e., 20 m shu le un, s anding long jump and 4 ˆ 10 m shu le un es s), whe eas a highe FFMI was associa ed wi h a be e pe o mance in all i ness es s in 4-yea -old child en. Hence, FM and FFM appea o ha e join bu opposi e associa ions wi h physical i ness. Ano he in e es ing inding was ha BMI was no associa ed wi h physical i ness in weigh -bea ing es s. Thus, he de ailed and accu a e body composi ion da a in his s udy made i possible o iden i y associa ions be ween body composi ion and physical i ness. These indings expand he cu en li e a u e since his is, o he bes o ou knowledge, he i s s udy epo ing associa ions o measu es o bo h FM and FFM wi h physical i ness in p eschoole s. 4.2. Compa ison wi h O he S udies in P eschoole s Ree es e al. [ 14 ] epo ed ha a highe %FM, as measu ed by skin olds, was associa ed wi h inc eased unning imes o he hal mile un es in p eschoole s. This inding can be compa ed o Agha-Alinejad e al. [ 15 ] who ound ha highe %FM as measu ed by skin olds was associa ed wi h lowe ca dio espi a o y i ness in 5–6-yea -old boys. Niede e e al. [ 13 ] assessed he physical i ness o 4–6 yea olds and epo ed ha o e weigh /obese p eschoole s had lowe ca dio espi a o y i ness and agili y compa ed o hei no mal-weigh pee s. Al hough Niede e e al. [ 13 ] did no epo he associa ion be ween %FM and physical i ness, hey s a ed ha hei esul s would ha e been simila i classi ica ion was based on %FM using bioimpedance ins ead o BMI. We could con i m hese indings using de ailed body composi ion da a since bo h FMI and %FM we e associa ed wi h wo se pe o mance in he 20 m shu le un (i.e., ca dio espi a o y i ness) and he 4 ˆ 10 m shu le un (i.e., mo o i ness) es s. Fu he mo e, we obse ed an associa ion be ween highe FMI and %FM and wo se pe o mance in he s anding long jump es which, o ou knowledge, has no been epo ed in p eschoole s p e iously. Ou obse ed associa ions emained s a is ically signi ican a e adjus men o objec i ely measu ed physical ac i i y, which ag ee wi h he esul s epo ed by Niede e e al. [ 13 ]. No p e ious s udy has epo ed associa ions be ween FFM and physical i ness in p eschoole s. Thus, ou epo ed associa ions o a highe FFMI and a highe physical i ness ep esen no el indings. Few s udies ha e in es iga ed he associa ions be ween BMI and physical i ness in p eschoole s. Al hough no a uni e sal inding [ 16 ], he e is some e idence ha a highe BMI is associa ed wi h lowe ca dio espi a o y i ness [ 11 – 15 ], mo o i ness/agili y [ 12 , 13 , 15 ] and lowe -body muscula s eng h [ 17 ] sugges ing ha a highe FM is ela ed o a lowe pe o mance in hese i ness es s. Indeed, ou esul s show ha a highe FMI, and also a lowe FFMI, is associa ed wi h a wo se pe o mance in he 20 m shu le un (i.e., ca dio espi a o y i ness), s anding long jump (i.e., lowe -body muscula s eng h) and 4 ˆ 10 m shu le un (i.e., mo o i ness) es s. Fu he mo e, p e ious s udies ha e epo ed ha a highe BMI is associa ed wi h a highe handg ip s eng h in p eschoole s [ 12 , 16 ]. Ou esul s con i m ha BMI is associa ed wi h handg ip s eng h and ha he a - ee componen o he weigh , i.e., he FFMI, was posi i ely ela ed o handg ip s eng h. Howe e , we obse ed no associa ions o BMI/BMI-g oups wi h ca dio espi a o y i ness, lowe -body muscula s eng h and mo o i ness in he cu en s udy. One eason o his disc epancy may be ha he child en in ou s udy we e as young as 4 yea s, because Niede e e al. [ 13 ] obse ed la ge di e ences in ca dio espi a o y i ness and agili y be ween no mal-weigh and o e weigh /obese 6-yea olds, bu in e es ingly no in 4-yea olds. 4.3. Compa ison wi h S udies in Olde Child en Ou esul s ag ee wi h p e ious indings in olde child en. In gene al, a highe FM o BMI has consis en ly been associa ed wi h a lowe ca dio espi a o y i ness in child en [ 5 – 8 , 30 ] and adolescen s [ 31 , 32 ]. Wi h ega ds o muscle s eng h, s udies ha e epo ed ha a highe FFM o Nu ien s 2016,8, 473 8 o 11 BMI is posi i ely associa ed wi h handg ip s eng h [ 30 , 31 , 33 ], whe eas a highe FM o BMI has been associa ed wi h wo se pe o mance in jumping es s [ 30 – 32 ]. These p e ious indings ag ee wi h ou epo ed associa ions o FFMI o BMI wi h handg ip s eng h as well as be ween FMI and s anding long jump. E idence has also been p esen ed indica ing ha a highe FM/BMI is ela ed o wo se pe o mance in he 4 ˆ 10 m shu le un es [ 31 , 32 ] o 40 m es [ 30 ] (i.e., mo o i ness), which ag ees wi h ou indings. 4.4. Di ec ion o he Associa ion be ween Body Composi ion and Physical Fi ness The di ec ion o he c oss-sec ional associa ions be ween body composi ion and physical i ness is no ob ious. Ma inez-Tellez e al. [ 12 ] a gued ha heal h- ela ed physical i ness can be seen as a ma ke o adiposi y and consequen ly de ined BMI as he independen a iable. We he e o e u he in es iga ed associa ions o physical i ness (x) wi h body composi ion (y) in Table S2. The esul s we e, as expec ed, e y simila o he ones p esen ed in Table 2. Thus, a be e pe o mance in weigh -bea ing es s was associa ed wi h a lowe FMI (all p ď 0.012) and a be e pe o mance in all es s was associa ed wi h a highe FFMI (all p ď 0.015). Hence, ou esul s may also be in e p e ed such ha highe physical i ness le els a e associa ed wi h a mo e a o able body composi ion p o ile, i.e., less FM and/o mo e FFM, al eady in 4-yea -old child en. We analyzed he associa ions o body composi ion (x) wi h physical i ness (y) since we deemed i mo e likely ha body composi ion in luences he physical i ness pe o mance, han ice e sa, in c oss-sec ional da a. This is in acco dance wi h mos s udies on p eschoole s [ 11 , 13 , 14 , 16 ]. Ne e heless, u he longi udinal s udies on p eschoole s a e wa an ed o u he examine he di ec ion o he associa ions be ween body composi ion and physical i ness. 4.5. S eng hs and Limi a ions This s udy has se e al limi a ions. Due o he c oss-sec ional design o he s udy, causali y and di ec ion o associa ions canno be concluded. Fu he mo e, he pa en s o he child en in his s udy we e well educa ed, which may limi gene alizabili y. Ne e heless, he child en in his s udy we e e y simila o a e age Swedish child en wi h ega ds o weigh and heigh as indica ed by he z-sco es in Table 1. The s eng hs o his s udy we e ha body composi ion was measu ed using accu a e me hodology [ 24 ] and he comp ehensi e physical i ness assessmen was pe o med using he PREFIT ba e y [ 25 ], which has been e alua ed in p eschoole s [ 34 ]. O he s eng hs we e ha we could p o ide es ima es o FMI and FFMI ha we e mu ually adjus ed o each o he and he objec i e accele ome e da a we e included o adjus associa ions. 4.6. In e p e a ion and Implica ions Zaqou e al. [ 30 ] obse ed ha lowe a BMI was associa ed wi h be e pe o mance in weigh -bea ing physical i ness es s and sugges ed ha BMI ep esen s a modi iable ac o o imp o e physical i ness in child en. Impo an ly, ou esul s sugges ha i is he componen s o BMI, i.e., less FMI and mo e FFMI, and no BMI pe se ha in luences he physical i ness o child en. The combined in luence o FM and FFM on physical i ness in his s udy was ela i ely s ong. Mo e speci ically, a dec ease in he FMI and an inc ease in he FFMI co esponding o one SD was associa ed wi h a be e pe o mance in he 20 m shu le un (+0.35 SD), s anding long jump (+0.39 SD) and 4 ˆ 10 m shu le un (+0.38 SD) in adjus ed models. Fu he mo e, a one SD inc ease in he FFMI was associa ed wi h a 0.39 SD highe hand g ip s eng h. We he e o e belie e ou iden i ied associa ions o FM and FFM wi h physical i ness a e s ong enough o be ele an . These indings may be o public heal h impo ance since physical i ness al eady in childhood is ela ed o u u e heal h [ 4 , 9 ]. Howe e , as poin ed ou by O ega e al. [25], he e is a g ea need o u u e s udies in es iga ing he in luence o physical i ness, in he p eschool-age, on la e heal h ou comes.