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Physical ac i i y in ensi y and olde adolescen s’ s ess : The ‘ST ess-Reac i i y a e
Exe cise in Senio Seconda y EDuca ion’ (STRESSED) 3-a m andomised con olled ial
© 2024 The Au ho (s). Published by Else ie L d.
Published e sion
Smi h, Jo dan J.; Beauchamp, Ma k R.; Pu e man, Eli; Leahy Angus, A.;
Valkenbo ghs, Sa ah R.; Wade, Le i; Chen, F ances; Lubans, Da id R.
Smi h, J. J., Beauchamp, M. R., Pu e man, E., Leahy Angus, A., Valkenbo ghs, S. R., Wade, L.,
Chen, F., & Lubans, D. R. (2025). Physical ac i i y in ensi y and olde adolescen s’ s ess : The
‘ST ess-Reac i i y a e Exe cise in Senio Seconda y EDuca ion’ (STRESSED) 3-a m andomised
con olled ial. Psychology o Spo and Exe cise, 76, A icle 102754.
h ps://doi.o g/10.1016/j.psychspo .2024.102754
2025
Physical ac i i y in ensi y and olde adolescen s’ s ess: The
‘ST ess-Reac i i y a e Exe cise in Senio Seconda y EDuca ion’
(STRESSED) 3-a m andomised con olled ial
Jo dan J. Smi h
a,b,*
, Ma k R. Beauchamp
c
, Eli Pu e man
c
, Angus A. Leahy
a,b
,
Sa ah R. Valkenbo ghs
a,b
, Le i Wade
a,b
, F ances Chen
d
, Da id R. Lubans
a,b,e
a
Cen e o Ac i e Li ing and Lea ning, College o Human and Social Fu u es, Uni e si y o Newcas le, Callaghan, Aus alia
b
Hun e Medical Resea ch Ins i u e, New Lamb on Heigh s, New Sou h Wales, Aus alia
c
School o Kinesiology, Uni e si y o B i ish Columbia, Vancou e , B i ish Columbia, Canada
d
Depa men o Psychology, Uni e si y o B i ish Columbia, Vancou e , B i ish Columbia, Canada
e
Facul y o Spo and Heal h Sciences, Uni e si y o Jy ¨
askyl¨
a, Jy ¨
askyl¨
a, Finland
ARTICLE INFO
Keywo ds:
School
In e en ion
Co isol
You h
Fi ness
ABSTRACT
Objec i es: La e adolescence (15–19 yea s) is a pe iod o heigh ened suscep ibili y o s ess, bu egula physical
ac i i y may a enua e eac i i y o s esso s. We aimed o explo e he e ec s o physical ac i i y in ensi y on
olde adolescen s’ s ess- eac i i y and sel - epo ed men al heal h.
Design and Me hods: Th ee-a m andomised con olled ial in New Sou h Wales, Aus alia (Ap il–June 2021).
Thi y-se en olde adolescen s (16.1 ±0.2 yea s, 59.5 % emale) we e andomised o: i) non-ac i e con ol
(CON), ii) ligh -in ensi y physical ac i i y (LPA), o iii) mode a e- o- igo ous-in ensi y physical ac i i y (MVPA).
Physical ac i i y g oups pa icipa ed in 2 x 20-min sessions/week o 6 weeks. Sali a y co isol (sCo ) eac i i y
o induced s ess was assessed using he T ie Social S ess Tes o G oups and quan i ied as a ea unde he cu e
(sCo
AUC
; P ima y ou come). Seconda y ou comes included peak co isol (sCo
Peak
), subjec i e- eac i i y,
pe cei ed s ess, and non-speci ic psychological dis ess. G oup di e ences we e assessed using mul iple linea
eg ession and quan i ied using Cohen’s d.
Resul s: No s a is ically signi ican e ec s we e obse ed o sCo
AUC
o sCo
Peak
and he pa e n o e ec s o
subjec i e- eac i i y was inconsis en . E ec s o sel - epo ed men al heal h we e also non-signi ican (p >.05
o all) bu o meaning ul magni ude, a ou ing LPA and MVPA o e CON (d’s = − 0.38 o −0.54). Deli e y
ideli y was high, sa is ac ion was mode a e- o-high, and he e was no e idence o ha m. Howe e , ec ui men ,
e en ion o sCo measu es, and adhe ence we e lowe han expec ed.
Conclusion: Subop imal ec ui men , e en ion, and adhe ence limi ed ou abili y o conclude on he e ec o
physical ac i i y in ensi y on olde adolescen s’ sCo - eac i i y o induced s ess. We obse ed po en ially
meaning ul e ec s on sel - epo ed men al heal h o bo h physical ac i i y condi ions, which could be con i med
in a u u e powe ed ial.
1. Backg ound
The inal yea s o seconda y school a e highly s ess ul o many
s uden s, wi h he no mal p essu es o ma u a ion compounded by high
s akes examina ions (Wu h ich e al., 2021). E idence sugges s he e
ha e been global inc eases in s ess and anxie y among young people in
ecen decades and school- ela ed s ess appea s o be a majo con ib-
u o (Swee ing e al., 2010). Indeed, ‘school challenges’ and ‘men al
heal h challenges’ a e among he mos equen ly ci ed pe sonal chal-
lenges iden i ied by olde adolescen s (15–19 yea s) (Leung e al., 2022).
Ch onic s ess has subs an ial ad e se impac s on s uden s’ well-being
and p edic s u u e men al illness (B ady & Sinha, 2005). S ess also
a ec s execu i e unc ioning (Shields e al., 2016), unde mining aca-
demic achie emen du ing a c i ical s age o educa ion. Gi en he
impo ance o school pe o mance o uni e si y en ance and
pos -school employmen , he e is a need o iden i y and unde s and
* Co esponding au ho . Cen e o Ac i e Li ing and Lea ning School o Educa ion, Uni e si y o Newcas le Callaghan, NSW, 2308, Aus alia.
E-mail add ess: [email p o ec ed] (J.J. Smi h).
Con en s lis s a ailable a ScienceDi ec
Psychology o Spo & Exe cise
jou nal homepage: www.else ie .com/loca e/psychspo
h ps://doi.o g/10.1016/j.psychspo .2024.102754
Recei ed 23 Janua y 2024; Recei ed in e ised o m 20 Sep embe 2024; Accep ed 26 Sep embe 2024
Psychology o Spo & Exe cise 76 (2025) 102754
A ailable online 1 Oc obe 2024
1469-0292/© 2024 The Au ho (s). Published by Else ie L d. This is an open access a icle unde he CC BY license (
h p://c ea i ecommons.o g/licenses/by/4.0/ ).
modi iable ac o s ha p omo e esilience o s ess du ing he inal yea s
o seconda y school.
A la ge body o e idence suppo s he impo ance o physical ac i i y
and physical i ness o young peoples’ men al heal h (Biddle e al.,
2019). Howe e , physical ac i i y declines p ecipi ously du ing
adolescence (Dumi h e al., 2011) and ewe han 1 in 5 adolescen s
globally acc ues he ecommended 60 min o mo e o daily
mode a e- o- igo ous in ensi y physical ac i i y (MVPA) (Gu hold e al.,
2020). The e ha e also been global declines in adolescen s’ physical
i ness (Tomkinson e al., 2021), which could ha e meaning ul impli-
ca ions o popula ion men al heal h. A ecen me a-analysis o >1
million pa icipan s ound inciden men al diso de s and suicidali y
we e ~40 % lowe among hose wi h highe ca dio espi a o y i ness
(CRF) du ing he peak isk pe iod o onse o adul -pa e n men al
diso de s (Tacchi e al., 2019). Whe he o no declining MVPA and
i ness a e a leading cause o he global ise in young peoples’ psycho-
logical dis ess emains unclea . Bu he link is plausible and in-
e en ions o suppo olde adolescen s’ physical ac i i y pa icipa ion
a e jus i ied, pa icula ly i he mos e ec i e p esc ip ion(s) can be
iden i ied and deployed a scale.
Despi e widesp ead ecogni ion o he psychological bene i s o
physical ac i i y, he e emains a lack o consensus on he unde pinning
mechanisms (Lubans e al., 2016). Howe e , a g owing li e a u e is
linking physical ac i i y-induced changes in cogni i e and men al heal h
wi h a ious neu obiological ac o s (Heinze e al., 2021). Among hese
is co isol, a p ima y end-p oduc o he physiological s ess esponse,
which may be meaning ully implica ed in he inc eased incidence o
common men al diso de s du ing adolescence. Fo example, he e a e
age- ela ed di e ences in co isol- eac i i y o an acu e s esso , wi h
e idence om one s udy (n =82) indica ing pos -pube al you h ha e
heigh ened eac i i y ela i e o p e-pube al you h (Gunna e al.,
2009). This e ec acks closely wi h he iming o sex-speci ic inc eases
in a es o men al ill-heal h be ween childhood and adolescence
(Law ence e al., 2016). In addi ion, co isol le el in childhood has been
shown longi udinally o p edic adolescen gi ls’ suscep ibili y o
dep ession ollowing nega i e li e e en s (LeMoul e al., 2015). LeMoul
and colleagues ound ha he associa ion be ween exposu e o nega i e
li e e en s and dep ession onse a age 18 depended on gi ls’ (n =62)
le el o diu nal sali a y co isol a age 9–14 (i.e., nega i e li e e en s
we e un ela ed o dep ession in gi ls wi h lowe baseline co isol)
(LeMoul e al., 2015).
While he e is compelling suppo o he ole o (pa icula ly
ch onically) ele a ed co isol p oduc ion in he onse o common men al
diso de s, he e a e also nuances ha make he associa ion di icul o
disen angle. Fo example, e idence sugges s men al heal h s a us is
meaning ully associa ed wi h co isol- eac i i y du ing adolescence, bu
in opposi e di ec ions o males and emales. In a s udy o 111 pa ici-
pan s, Mazu ka and colleagues (Mazu ka e al., 2018) ound ha 12–18
yea old boys wi h dep ession demons a ed an ele a ed co isol
esponse o a lab-based s esso ( ela i e o non-dep essed boys and
gi ls), whe eas dep essed gi ls had a blun ed co isol esponse. This s udy
highligh s he impo ance o conside ing men al heal h s a us and sex
when explo ing he e ec s o in e en ions on co isol- eac i i y. Li e-
s yle ac o s a e also impo an o conside , wi h s udies showing sleep
(n =31) (Capaldi e al., 2005) and die a y beha iou s (n =60) (Shea e
e al., 2016) (and by ex ension adiposi y, n =63 (Roemmich e al.,
2007)) a e also ela ed o co isol le el in you h. Howe e , o he
pu poses o he p esen in es iga ion, i is he ole physical ac i i y in
suppo ing heal hy co isol egula ion ha is he li es yle ac o o in-
e es . The e is consis en e idence suppo ing a link be ween you hs’
physical ac i i y and sel - epo ed ‘pe cei ed’ s ess (Moljo d e al.,
2011; W igh e al., 2023), which could be explained by he e ec s o
physical ac i i y on unde lying s ess physiology.
Almos h ee decades ago, So hmann and colleagues (So hmann
e al., 1996) sugges ed he s ess-bu e ing e ec s o physical ac i i y
could be he esul o adap a ions o he sys ems egula ing he s ess
esponse. Coined he ‘C oss-S esso Adap a ion hypo hesis’ (he ea e
CSA), egula exposu e o he ‘physical’ s ess o su icien ly in ense
exe cise is posi ed o modi y he s imula ion o he sympa he ic ne ous
sys em and hypo halamic-pi ui a y-ad enal (HPA) axis, leading o
blun ed ca dio ascula - and ad enoco ical- (i.e., co isol) eac i i y o
‘psychosocial’ s esso s (So hmann e al., 1996). Despi e conside able
esea ch a en ion, empi ical suppo o CSA emains somewha
inconsis en . Fo example, in a ecen sys ema ic e iew (Mücke e al.,
2018) highe physical ac i i y and CRF we e associa ed wi h a enua ed
sali a y co isol (sCo ) eac i i y in ~60 % o s udies (median n =84)
using he T ie Social S ess Tes (TSST), a highly alid and widely-used
psychosocial s ess induc ion pa adigm. Howe e , e y ew included
s udies we e conduc ed wi h school-aged you h (none wi h olde ado-
lescen s) and almos all we e obse a ional.
To ou knowledge, he e has no been a single andomised con olled
ial (RCT) assessing he e ec s o physical ac i i y on adolescen s’
co isol- eac i i y o induced psychosocial s ess, despi e his being a
highly salien and consequen ial issue o his g oup. The dea h o
expe imen al esea ch makes i di icul o judge he sui abili y o CSA as
a guiding amewo k o designing physical ac i i y-based s ess-man-
agemen in e en ions. The e o e, he aim o ou explo a o y s udy was
o in e oga e he assump ions o CSA by es ing he mode a ing ole o
physical ac i i y in ensi y on olde adolescen s’ sCo - eac i i y o a
s anda dised s esso . Consis en wi h he p edic ions o CSA, we
hypo hesised ha adolescen s pa icipa ing in MVPA would show a
meaning ul decline in sCo - eac i i y o induced psychosocial s ess,
bu ha no e ec would be ound o ligh -in ensi y physical ac i i y.
2. Ma e ials and me hods
2.1. S udy design and pa icipan s
The conduc and epo ing o ou s udy complies wi h he consoli-
da ed s anda ds o epo ing ials (CONSORT) ex ension o mul i-a m
pa allel-g oup RCTs (Juszczak e al., 2019) and he empla e o in e -
en ion desc ip ion and eplica ion (TIDieR) (Ho mann e al., 2014).
E hical app o al was ob ained om he Uni e si y o Newcas le
(H-2019-0410) and he Ca holic Schools O ice o he Diocese o
Mai land-Newcas le. All pa icipan s/pa en s p o ided in o med
assen /consen p io o en olmen . A 3-a m pa allel-g oup RCT was
conduc ed a a single non-go e nmen seconda y school in New Sou h
Wales (NSW), Aus alia (ACTRN12621000672853). Eligible pa ici-
pan s we e s uden s in G ade 11 (i.e., penul ima e yea o seconda y
school; ~16–17 yea s old) wi hou an inju y/illness ha would p eclude
pa icipa ion in MVPA. Gi en he lack o p io esea ch on
co isol- eac i i y o induced s ess wi h his s udy popula ion, we
conduc ed an explo a o y ( a he han con i ma o y) ial ha is
in ended o in o m a u u e powe ed ial. Thus, we aimed o ec ui a
o al o 60 pa icipan s (20 pe ea men a m), which ep esen s he
minimum ecommended sample size o a p elimina y ial designed o
in o m a subsequen main ial (wi h 90 % powe , wo-sided 5 % sig-
ni icance, assuming a s anda dised e ec size o 0.5) in la ed by 5 pa -
icipan s pe a m o accoun o possible d op-ou (Whi ehead e al.,
2016). Rec ui men occu ed du ing a 5-week pe iod in he school e m
p io o he commencemen o he ial (Ma ch–Ap il 2021).
2.2. Randomisa ion and blinding
Gi en he impo ance o sex and men al heal h s a us on adolescen s’
co isol esponses o induced s ess (Mazu ka e al., 2018), pa icipan s
we e s a i ied p io o andomisa ion by sex (male/ emale) and baseline
psychological dis ess (i.e., K-10 sco e <25 [likely o be well/likely mild
men al diso de ] o ≥25 [likely mode a e/se e e men al diso de ])
(And ews & Slade, 2001). A e baseline assessmen s, he lead in es i-
ga o used an online andom numbe gene a o o alloca e s a i ied
pa icipan s in blocks o h ee (1:1:1 a io) o ei he a non-ac i e con ol
J.J. Smi h e al.
Psychology o Spo & Exe cise 76 (2025) 102754
2
g oup (usual ca e; CON), a ligh -in ensi y physical ac i i y g oup (LPA),
o a mode a e- o- igo ous in ensi y physical ac i i y g oup (MVPA).
Ou come assesso s we e blind o g oup alloca ion and analyses we e
conduc ed by a blinded s a is ician independen o he in es iga o
eam. Pa icipan s we e pa ially blinded, in ha hose alloca ed o LPA
and MVPA we e no awa e o he p ima y hypo hesis bu we e awa e o
hei alloca ion o an in e en ion g oup a he han con ol. Pe sonnel
deli e ing he exe cise sessions we e no blinded.
2.3. Physical ac i i y in e en ions
Pa icipan s in he LPA and MVPA g oups we e encou aged o a end
2 x 20-min sessions/week ( om ou o e ed) o 6 weeks and gi en a
small incen i e each week i hey me his a ge (i.e., ee ho be e age).
They also ecei ed a inancial incen i e ($50AUD) o a ending ≥10
sessions in o al o e he 6-week in e en ion pe iod. Al hough his
exe cise dose is ela i ely low, he e is e idence ha sho , wice-weekly
exe cise sessions deli e ed a a su icien ly high in ensi y can al e
ad enoco ical ma ke s o s ess in olde adolescen s (Lubans e al.,
2021). Mo eo e , ime is a key ba ie o he implemen a ion o exe cise
p og ams in schools, and so i is impo an o e alua e an in e en ion
model ha is ealis ic o a ypical school (and which migh e lec a
minimally e ec i e dose). Finally, a 6-week exe cise in e en ion
enabled baseline and pos - es assessmen s o occu immedia ely p io o
and ollowing p og am deli e y, wi hou being impac ed by he subse-
quen 2-week school holiday b eak, which migh ha e esul ed in a
‘wash ou ’ o immedia e pos -in e en ion e ec s i s udy measu es we e
collec ed a e wa ds. Sessions we e deli e ed on school p emises a he
same ime o day o bo h LPA and MVPA by wo Physical
Educa ion-quali ied membe s o he esea ch eam, who egula ly
al e na ed be ween g oups. Sessions we e deli e ed in acco dance wi h
a published amewo k o pedagogical p inciples (Lubans e al., 2017)
wi h which bo h acili a o s had ex ensi e p io expe ience.
The physical ac i i y modali ies o each g oup we e selec ed o elici
he in ended ca dio ascula esponse, and because hey we e p ac ically
easible o deli e y in schools. LPA ecei ed wo ypes o g oup-based
sessions in ol ing ligh -in ensi y physical ac i i y (i.e., <64 % o age-
p edic ed maximum hea a e [HR
max
]): i) yoga-inspi ed s e ching
deli e ed indoo s wi h elaxing slow- empo music, and ii) leisu ely
walking conduc ed ou doo s a ound he ex e nal pe ime e o he
school. Pa icipan s in he MVPA condi ion comple ed g oup-based in-
e al aining sessions designed o elici a HR esponse in he mode a e-
o- igo ous in ensi y band (i.e., ≥64 % HR
max
). Sessions we e deli e ed
indoo s wi h high- empo music and included a combina ion o ae obic
(e.g., jumping jacks) and bodyweigh esis ance (e.g., push-ups)
exe cises.
2.4. Assessmen p ocedu e
S udy assessmen s and in e en ion deli e y occu ed wi hin a single
10-week school e m be ween Ap il–June 2021. Baseline and pos - es
assessmen s occu ed in he wo weeks ei he side o in e en ion de-
li e y. Pa icipan s we e p o ided wi h a mode a e inancial incen i e
($50AUD) o comple ing s udy assessmen s a each ime poin . S an-
da d demog aphic in o ma ion and sel - epo ou comes we e e alua ed
using an online su ey. sCo - eac i i y measu es we e collec ed by
ained esea ch assis an s on school p emises.
2.5. S udy measu es
2.5.1. sCo - eac i i y o acu e psychosocial s ess (p ima y ou come)
S ess- eac i i y was assessed using he T ie Social S ess Tes o
G oups [TSST-G] (Von Dawans e al., 2011). Al hough he TSST has been
used a baseline and pos - es in an RCT (Ge be e al., 2020), esea ch
shows dampened sCo - eac i i y wi h subsequen adminis a ions
implying habi ua ion o he s esso (Ko hgassne e al., 2021). To
p ese e he e icacy o he s ess induc ion a pos - es as well as ac-
coun ing o baseline di e ences, we employed an al e na i e p o ocol
a baseline - he Socially E alua ed Cold P esso Task (SECPT) (Schwabe
e al., 2008). The SECPT and TSST-G a e dis inc p o ocols, bu bo h
inco po a e mo i a ed pe o mance, uncon ollabili y, and
social-e alua i e h ea o elici HPA-axis ac i a ion (Schwabe e al.,
2008; Von Dawans e al., 2011). Bo h p o ocols we e conduc ed on
school p emises be ween 1300h and 1530h o con ol o diu nal cycle
o co isol, and pa icipan s we e ins uc ed no o ea o d ink (wa e
accep ed) o engage in exe cise o a leas 2 h p io . Sali a samples we e
ozen and s o ed a −20 ◦C un il shipped o analysis by a comme cial
labo a o y (D esden Lab Se ice GmbH, Ge many). A e hawing, Sal-
i e es we e cen i uged a 3000 pm o 5 min, which esul ed in a clea
supe na an o low iscosi y. sCo concen a ions (nmol/L) we e
measu ed in duplica e using comme cially a ailable chemiluminescence
immunoassay wi h high sensi i i y (IBL In e na ional, Hambu g, Ge -
many). The in a- and in e -assay coe icien s o a ia ion o sCo we e
bo h below 9 %. Fu he de ails o he SECPT and TSST-G p o ocol a e
p o ided below.
Socially E alua ed Cold P esso Task. Upon a i al, pa icipan s
en e ed a small oom wi h a male expe imen e wea ing a whi e lab coa
and p o ided a sali a sample (−5 min om s esso onse [T0]) using
comme cially a ailable low densi y polye hylene swabs (Sali e e®;
Sa s ed , Romelsdo , Ge many). The pa icipan was in o med hey
would be ideo eco ded so hei acial exp essions could be analysed
la e by expe s and hen asked o imme se hei hand in cold wa e
(0–4 ◦C) o as long as hey could ole a e (p e-speci ied end poin [T0
+3 min] no disclosed). The expe imen e obse ed om a posi ion
isible o he pa icipan , pe iodically making no es o induce social-
e alua i e h ea , while he pa icipan looked con inuously a he
came a (Apple iPad 6). A e 3 min, pa icipan s we e old o emo e
hei hand and immedia ely a ed how ‘unpleasan ’ and ‘s ess ul’ he
expe ience was using an 11-poin scale (0 =no a all o 100 = e y much)
be o e p o iding a second sali a sample (T0 +5 min). They hen mo ed
o a nea by wai ing oom o he eco e y pe iod whe e ano he ou
sali a samples we e collec ed (T0 +15, +25, +35, and +45 min). Pa -
icipan s we e gi en non-s imula ing eading ma e ial o pass he ime
and we e ins uc ed no o in e ac wi h anyone. To p e en hem om
in e ing he objec i es o he s ess-induc ion a pos - es , hey we e no
deb ie ed on he pu pose o he SECPT.
T ie Social S ess Tes o G oups. The TSST-G is a s anda dised g oup-
based s ess induc ion p o ocol ha consis s o h ee phases: i) in o-
duc ion, p epa a ion and an icipa ion, ii) public speaking (mock job
in e iew), and iii) challenging men al a i hme ic. Upon a i al, g oups
o 5 pa icipan s en e ed a oom wi h a male expe imen e whe e hey
we e old hey would ha e 10 min o p epa e a 2 min speech o a panel
o judges on why hey would be a sui able candida e o a sel -selec ed
ideal job. They we e also in o med o an unspeci ied second ask o
which hey could no p epa e. Following his, pa icipan s mo ed o a
nea by oom o commence he public speaking ask. They s ood acing
he panel (one male and one emale wea ing whi e lab coa s), sepa a ed
by mobile di iding walls ha es ic ed eye con ac and social in e ac-
ion wi h o he pa icipan s. The panel had been ins uc ed no o p o-
ide any e bal o non- e bal eedback du ing he ask. Pa icipan s
we e old hey would be ideo eco ded o la e expe e iew, a e
which he panel selec ed pa icipan s in andom o de o comple e hei
speech. Fo he a i hme ic ask, pa icipan s we e gi en a unique 4 digi
s a ing numbe and asked o se ially sub ac 13 as many imes as
possible o 80 s. I hey made a mis ake, he panel ins uc ed hem o
s a again. Once all pa icipan s had comple ed he a i hme ic ask, hey
epo ed how ‘unpleasan ’ and ‘s ess ul’ he expe ience was using an 11-
poin scale (0 =no a all o 100 = e y much) be o e e u ning o he
p epa a ion oom o he eco e y pe iod. Sali a samples we e collec ed
upon a i al (T0 −12 mins), pos -p epa a ion (T0), pos -speech (T0 +12
min), pos -a i hme ic (T0 +20 min), and a i e poin s du ing eco e y
(T0 +30, +40, +50, +60 and +70 min). Once he inal sali a sample was
J.J. Smi h e al.
Psychology o Spo & Exe cise 76 (2025) 102754
3
collec ed, he expe imen e deb ie ed pa icipan s on he pu pose o he
TSST-G (and SECPT a baseline), e ealing he asks we e in ended o
elici s ess and emphasising ha hey had pe o med well.
2.5.2. Pe cei ed s ess
Pe cei ed s ess was assessed using he Pe cei ed S ess Scale (PSS)
(Cohen e al., 1983), which includes 10 i ems ela ing o he equency
o esponden s’ expe ience o s ess o e he pas mon h (e.g., How o en
ha e you el ha you we e on op o hings?). Pa icipan s esponded using
a 5-poin scale (0 =Ne e o 4 =Ve y o en) and esponses we e summed
o p oduce a o al sco e (possible ange =0 o 40). The in e nal con-
sis ency among he p esen sample a baseline was good (C onbach
α
=
.87).
2.5.3. Psychological dis ess
Non-speci ic psychological dis ess was assessed using he Kessle -10
(K-10) (Kessle e al., 2003), which is a widely-used psychological
sc eening ins umen alid o use wi h adolescen s. The K-10 includes
10 i ems ela ing o he equency o in e nalising symp oms expe i-
enced o e he pas mon h (e.g., In he pas 4 weeks, abou how o en did
you eel hopeless). Pa icipan s esponded using a 5-poin scale (1 =None
o he ime o 5 =All o he ime), and i ems we e summed o p oduce a
o al psychological dis ess sco e (possible ange =10 o 50). In e nal
consis ency among he p esen sample a baseline was good (C onbach
α
=.93).
2.5.4. P ocess measu es
The ollowing p ocess da a we e collec ed: i) ec ui men , p opo ion
o he a ge sample size en olled; ii) e en ion, pa icipan d op-ou a e
and p opo ion comple ing pos - es assessmen s; iii) adhe ence, o al
sessions comple ed and p opo ion sa is ying a endance a ge
(ins uc o log); i ) sa is ac ion, sa is ac ion wi h exe cise sessions (“I
enjoyed pa icipa ing in he exe cise sessions” om 1 [S ongly disag ee] o 5
[S ongly ag ee]); ) ideli y, mean/peak physical ac i i y in ensi y using
ches -wo n Pola ™ H9 Blue oo h HR moni o s wo n du ing all sessions;
and i) po en ial ha ms, inju ies/ad e se e en s om physical ac i i y
sessions o assessmen s (ad e se e en egis e ).
2.6. S a is ical analysis
All analyses we e conduc ed using SAS so wa e (SAS inc. Ca y, NC,
USA) by an independen s a is ical se ice ope a ed by he Hun e
Medical Resea ch Ins i u e. P io o he main analysis, we i s es ed he
e icacy o he s ess induc ion using: i) an inc ease o ≥15.5 % in aw
sCo alues (nmol/L) om baseline o indi idual peak o dis inguish
esponde s om non- esponde s a each imepoin (Mille e al., 2013),
and ii) one-way analyses o a iance (ANOVAs) wi h epea ed measu es
o de e mine he main e ec o ime on sCo (p <.05). We es ed he
e icacy o he TSST-G a pos - es using pa icipan s in CON and LPA
only, as ou p ima y hypo hesis assumed co isol- eac i i y would be
a enua ed o hose alloca ed o he MVPA g oup.
To quan i y s ess- eac i i y, sCo da a we e i s log- ans o med o
accoun o skewness hen con e ed o a ea unde he cu e wi h
espec o g ound (sCo
AUC
; P ima y ou come). Peak co isol (sCo
Peak
)
was calcula ed as he di e ence be ween log- ans o med sCo con-
cen a ion o SECPT samples 1 and 4 a baseline and TSST-G samples 1
and 5 a pos - es , which co espond wi h he expec ed iming o peak
co isol (Dicke son & Kemeny, 2004). Consis en wi h he
in en ion- o- ea p inciple, missing sCo
AUC
alues we e impu ed so all
en olled pa icipan s we e included in he analysis o he p ima y
ou come. Missing alues o sCo
AUC
(baseline o ollow-up) we e
mul iply impu ed and combined using Rubin’s Rules. The ully condi-
ional speci ica ion (wi h eg ession p opensi y mean ma ching) me hod
was used, and da a we e impu ed 25 imes. Baseline sCo
AUC
was
calcula ed using sex and he non-missing alues a baseline as p e-
dic o s. Pos - es sCo
AUC
was calcula ed using he baseline alues, sex,
and he non-missing sCo
AUC
a ollow-up as p edic o s. Comple e case
analyses we e conduc ed o all o he ou comes. G oup di e ences we e
analysed using mul iple linea eg ession, wi h baseline alues o he
dependen a iable and ea men g oup as co a ia es. Cohen’s d e ec
size was calcula ed wi h alues o <0.2, 0.2, 0.5, and 0.8 ep esen ing
negligible, small, medium, and la ge e ec s, espec i ely.
3. Resul s
The low o pa icipan s appea s in Figu e 1 and baseline cha ac-
e is ics a e p o ided in Table 1. A o al o 37 pa icipan s (Mean ±SD
age =16.1 ±0.2; 59 % emale) we e assessed a baseline and ando-
mised o ea men g oups. Th ee pa icipan s (all emale) wi hd ew
om he s udy a e baseline assessmen s, esul ing in 34 pa icipan s
(92 %) e ained a pos - es . Based on K-10 sco es, he ull sample was
gene ally men ally well a baseline. Howe e , 4 (10.8 %) pa icipan s
we e conside ed likely o ha e a mode a e men al diso de and 7 (18.9
%) pa icipan s we e conside ed likely o ha e a se e e men al diso de .
3.1. E ec s on s ess- eac i i y
A baseline, 9/31 (29.0 %) pa icipan s we e classi ied as non-
esponde s o he SECPT. The main e ec o ime was no s a is ically
signi ican F(1,28) =2.42, p =.131,
η
2
=0.08, sugges ing he s ess
induc ion was no as obus as in ended (Figu e 2). A pos - es , 7/19
(36.8 %) pa icipan s we e classi ied as non- esponde s o he TSST-G.
The main e ec o ime was s a is ically signi ican F(1,17) =5.31, p
=.034,
η
2
=0.24, sugges ing sCo inc eased as expec ed in esponse o
he s esso (Figu e 3). Baseline-adjus ed pos - es mean alues by g oup
and adjus ed mean di e ences (wi h 95 % con idence in e als [CI])
be ween LPA, MVPA and CON a e p o ided in Table 2. No s a is ically
signi ican o p ac ically meaning ul g oup di e ences in sCo
AUC
we e
obse ed. Compa ed wi h CON, sCo
AUC
a pos - es (n =37) was 6 %
lowe (95%CI = − 53 % o 89 %; p =.863; d = − 0.08) o LPA and 1 %
highe (95%CI = − 55 % o 123 %; p =.974; d =0.02) o MVPA. G oup
di e ences o sCo
Peak
(n =25) we e also non-signi ican , negligible in
size and showed no bene i o LPA o MVPA o e CON. Di e ences in
subjec i e- eac i i y (n =29) we e non-signi ican , mos ly negligible- o-
small and inconsis en in di ec ion. Al hough, he e was a small- o-
medium e ec size (d = − 0.30) o pe cei ed s ess ul a ou ing MVPA
o e CON, and a la ge e ec size (d =0.86) o pe cei ed unpleasan
a ou ing CON o e MVPA.
3.2. E ec s on sel - epo ed men al heal h
In e en ion e ec s o he PSS and K-10 (n =34 o bo h) we e all
no s a is ically signi ican . This said, he e ec sizes a ou ed he
physical ac i i y g oups and we e o small- o-mode a e magni ude. Fo
example, pe cei ed s ess was lowe among LPA (−2.0 uni s, 95%CI =
−6.7 o 2.6; p =.378; d = − 0.38) and MVPA (−2.8 uni s, 95%CI = − 7.2
o 1.7; p =.219; d = − 0.52) ela i e o CON. Simila ly, di e ences in K-
10 sco es also a ou ed LPA (−2.7 uni s, 95%CI = − 7.1 o 1.7; p =.222;
d = − 0.54) and MVPA (−1.9 uni s, 95%CI = − 6.1 o 2.3; p =.357; d =
−0.38) o e CON, hough again hese e ec s we e no s a is ically
signi ican .
3.3. P ocess indings
We en olled less han wo hi ds o he a ge sample size (37/60;
61.7 %) and while he d op-ou a e was low (8.1 %), he e en ion a e
o pos - es measu es was a iable, anging om 67.6 % o comple e s
o sCo measu es o 100 % o PSS and K-10. Pa icipan s in he LPA
and MVPA g oups comple ed a mean ±SD o 9.1 ±3.7 and 6.6 ±4.3
physical ac i i y sessions, espec i ely, wi h ewe han hal in each
g oup comple ing ≥10 sessions (i.e., n =4 o LPA and n =5 o MVPA).
LPA and MVPA indica ed high (4.5 ±0.5 ou o 5) and mode a e (3.7 ±
J.J. Smi h e al.
Psychology o Spo & Exe cise 76 (2025) 102754
4
1.1 ou o 5) sa is ac ion wi h he physical ac i i y sessions, espec i ely.
HR da a showed he in ensi y manipula ion was e ec i e, wi h mean ±
SD session in ensi y alues o 54.6 ±0.6 % and 68.8 ±8.7 % HR
Max
o
LPA and MVPA, espec i ely. A simila pa e n was ound o peak
session in ensi y, wi h mean ±SD alues o 68.8 ±8.7 % HR
Max
o LPA
and 83.4 ±7.7 % HR
Max
o MVPA. No inju ies o ad e se e en s we e
eco ded. Con e sa ions wi h school s a iden i ied ha wo o he h ee
s udy d opou s had wi hd awn om school due o men al heal h con-
ce ns, bu s a con i med his was un ela ed o hei pa icipa ion in he
ial.
4. Discussion
S ess- ela ed men al ill-heal h is a pe asi e and consequen ial issue
o olde adolescen s (Leung e al., 2022), and he inal yea s o sec-
onda y school a e an oppo une ime o in e ene. The aims o ou
explo a o y s udy we e o in es iga e he in luence o physical ac i i y
in ensi y on adolescen s’ sCo - eac i i y o induced psychosocial s ess
(p ima y ou come) and sel - epo ed men al heal h. Encou agingly,
s udy d op-ou was low, sa is ac ion was mode a e- o-high, he e we e
no ad e se e en s, e en ion o sel - epo ou comes was high, and
deli e y ideli y was s ong. Howe e , he e was also subop imal
pa icipan ec ui men , subs an i e missing da a o he p ima y
ou come, and poo pa icipan adhe ence wi h he physical ac i i y in-
e en ions (pa icula ly o he MVPA condi ion). As a esul , ou abili y
o conclude on he e ec o in ensi y on adolescen s’ s ess- eac i i y
was limi ed. O no e, he ial was conduc ed in he con ex o he
COVID-19 pandemic and concluded immedia ely p io o a second
ound o ex ended s ay-a -home o de s in he s a e o New Sou h Wales,
which likely in luenced s udy ec ui men and pa icipa ion.
We did no obse e any in e en ion e ec s o adolescen s’
ad enoco ical- eac i i y o acu e s ess, as measu ed by sCo
AUC
(n =
Figu e 1. Flow o pa icipan s h ough he s udy.
J.J. Smi h e al.
Psychology o Spo & Exe cise 76 (2025) 102754
5
37) and sCo
Peak
(n =25). The adjus ed pos - es mean di e ences be-
ween bo h physical ac i i y g oups and CON we e negligible. The e a e
se e al po en ial explana ions o hese esul s. Fi s , i is no clea
whe he HPA- eac i i y in ypically de eloping adolescen s is
‘dys unc ional’ enough ha i can be al e ed. Klape ski e al. (Klape ski
e al., 2014) ound educed co isol- and HR- eac i i y in esponse o he
TSST among a g oup o 149 adul men pa icipa ing in a 12-week ca -
dio ascula aining p og am (2 ×60 min/week). Con e sely, Ge be
e al. (Ge be e al., 2020) epo ed no e ec o a 6-week (3 x 40–50
min/week) ae obic exe cise p og am on co isol- eac i i y among a
mixed-sex g oup o 25 adul s wi h majo dep essi e diso de . To ou
knowledge, hese a e he only wo ials ha ha e es ed he e ec s o an
exe cise p og am on co isol- eac i i y o he TSST. Co isol- eac i i y o
he TSST ollowing an acu e bou o physical ac i i y has been shown o
a y by in ensi y in a ecen ial wi h 83 adul males (Caplin e al.,
2021), bu he gene alisabili y o hese indings o adolescen s, emales,
o ch onic physical ac i i y is unclea . Mo e esea ch examining he
e ec s o exe cise on ma ke s o HPA-axis unc ion in school-aged you h
is needed.
Due o he p io i y placed on cu icula ime, in he p esen ial
school s a limi ed he physical ac i i y sessions o he be o e school,
lunch ime, and a e school pe iods. This es ic ed he du a ion o 20
min o allow su icien a el ime o/ om school and o p e en s u-
den s being la e o classes. Acco ding o a ecen me a-analysis
(Rod iguez-Ayllon e al., 2019), he e ec s o physical ac i i y in-
e en ions on you h men al heal h a e mode a ed by du a ion, wi h
p og ams acili a ing ≥60 min/week o physical ac i i y achie ing an
e ec size app oxima ely h ee imes la ge han hose acili a ing <60
min. Whe he his inding ex ends o s ess- eac i i y is unclea , bu as
only 40 min/week was p esc ibed in ou ial, i is plausible his was an
insu icien dose o s imula e HPA-axis habi ua ion. Beyond he weekly
dose and equency o exe cise sessions, i is also plausible ha 6-weeks
was an insu icien o e all du a ion o elici imp o emen s in
co isol- eac i i y. In a me a-analysis o he e ec s o exe cise in-
e en ions on anxie y in college s uden s (Lin & Gao, 2023), he
s onges e ec s we e ound o in e en ions deli e ed o 8–14 weeks,
whe eas he pooled e ec o ials <8 weeks long was non-signi ican .
Simila indings we e ecen ly epo ed by Singh and colleagues (Singh
e al., 2023) in hei umb ella e iew o physical ac i i y in e en ions
o dep ession, anxie y and dis ess. Though ocused on heal hy adul s
(no you h), hey epo ed ha he op imal in e en ion du a ion was
≤12 weeks. We he e o e sugges a 6-week exe cise pe iod may be
insu icien o meaning ully imp o e ma ke s o s ess in olde adoles-
cen s (pa icula ly gi en subop imal pa icipan adhe ence), and ha a
minimum o 8-weeks is p uden o u u e ials.
Reduc ions in olde adolescen s’ (n =298) hai co isol concen a-
ions we e ound in he Bu n 2 Lea n (B2L) ial (Lubans e al., 2021)
Table 1
Cha ac e is ics o s udy sample a baseline.
Cha ac e is ics All (N =
37)
CON (n =
13)
LPA (n =
12)
MVPA (n
=12)
Age, yea s, mean (SD) 16.1
(0.2)
16.1 (0.3) 16.0
(0.0)
16.1 (0.3)
Female sex, n (%) 22 (59.5) 7 (53.8) 7 (58.3) 8 (66.7)
Coun y o bi h, n (%)
Aus alia 33 (89.2) 9 (69.2) 12 (100) 12 (100)
O he 4 (10.8) 4 (30.8) 0 (0.0) 0 (0.0)
P ima y language spoken a home, n (%)
English 37 (100) 13 (100) 12 (100) 12 (100)
O he 0 (0.0) 0 (0.0) 0 (0.0) 0 (0.0)
Cul u al backg ound, n (%)
Aus alian 28 (75.7) 8 (61.5) 10 (83.3) 10 (83.3)
Eu opean 4 (10.8) 2 (15.4) 1 (8.3) 1 (8.3)
Asian 2 (5.4) 0 (0.0) 1 (8.3) 1 (8.3)
A ican 2 (5.4) 2 (15.4) 0 (0.0) 0 (0.0)
Middle Eas e n 1 (2.7) 1 (7.7) 0 (0.0) 0 (0.0)
Indigenous descen , n (%) 1 (2.7) 0 (0.0) 1 (8.3) 0 (0.0)
Ma e nal educa ional a ainmen , n (%)
Unsu e 4 (10.8) 1 (7.7) 2 (16.7) 1 (8.3)
Didn’ comple e high
school
2 (5.4) 1 (7.7) 1 (8.3) 0 (0.0)
G ade 10 school ce i ica e 9 (24.3) 3 (23.1) 3 (25.0) 3 (25.0)
G ade 12 highe school
ce i ica e
3 (8.1) 2 (15.4) 1 (8.3) 0 (0.0)
Voca ional ce i ica e 3 (8.1) 0 (0.0) 2 (16.7) 1 (8.3)
Uni e si y unde g adua e
deg ee
7 (18.9) 3 (23.1) 2 (16.7) 2 (16.7)
Uni e si y pos g adua e
deg ee
9 (24.3) 3 (23.1) 1 (8.3) 5 (41.7)
K-10 likelihood o men al diso de , n (%)
Likely o be well (sco e =
10–19)
15 (40.5) 6 (46.2) 5 (41.7) 4 (33.3)
Likely mild diso de
(sco e =20–24)
11 (29.7) 3 (23.1) 3 (25.0) 5 (41.7)
Likely mode a e diso de
(sco e =25–29)
4 (10.8) 1 (7.7) 1 (8.3) 2 (16.7)
Likely se e e diso de
(sco e =30–50)
7 (18.9) 3 (23.1) 3 (25.0) 1 (8.3)
No e. CON, non ac i e con ol g oup; K-10, Kessle -10; LIGHT, ligh -in ensi y
physical ac i i y g oup; MVPA, mode a e- o- igo ous in ensi y physical ac i -
i y g oup; SD, s anda d de ia ion.
Figu e 2. Sali a y co isol esponse cu es o he Socially E alua ed Cold P esso Task a baseline No e. Shaded a ea ep esen s he s ess induc ion pe iod. Time is
gi en ela i e o s esso onse (i.e., 0 min). E o ba s ep esen s anda d e o o he mean.
J.J. Smi h e al.
Psychology o Spo & Exe cise 76 (2025) 102754
6
ha employed 2 ×10 min o high-in ensi y in e al aining pe week,
sugges ing ha sho du a ion igo ous in ensi y ac i i y can educe
ad enoco ical ma ke s o s ess. Howe e , B2L was deli e ed o e 16
weeks and he di e ence in dose ecei ed migh explain he disco dan
indings. In addi ion, B2L was deli e ed du ing cu icula ime and
adhe ence was likely highe han in ou ial, gi en sessions we e
deli e ed du ing manda o y classes. The MVPA g oup in he p esen
s udy comple ed only 6.6 sessions (ou o 12) on a e age, and ewe han
hal sa is ied he 80 % a endance a ge . This is likely o ha e in luenced
he indings o sCo - eac i i y and ein o ces he alue o deli e ing
physical ac i i y du ing manda ed pe iods o he school day. While
schools migh mo e eadily adop p og ams ha do no in e e e wi h
exis ing pa s o he school day (i.e., be o e/a e school, o b eak- ime),
such p og ams may be less e ec i e gi en hey ely on you h o op -in o
a non-manda o y oppo uni y and so migh appeal mos ly o hose wi h
an exis ing in e es in spo and exe cise. We sugges u u e ials explo e
ways o p o ide physical ac i i y oppo uni ies ha each mos (o all)
you h du ing manda ed pe iods ha do no ely hea ily on s uden
mo i a ion.
Finally, he inclusion o bo h emales and males in he s udy sample
could ha e con ibu ed o he null sCo e ec s. O en, s udies explo ing
ad enoco ical- eac i i y o induced s ess use male-only samples o
a oid he con ounding e ec s o mens ual cycle and/o ho monal
con acep i es (Caplin e al., 2021). Al e na i ely, esea che s may
include emales bu collec in o ma ion on mens ual iming and con-
acep i e use so his can be accoun ed o in he inclusion c i e ia,
andomisa ion o analyses. We el limi ing he s udy o males was
p oblema ic because: i) emales epo wo se men al heal h han males
du ing adolescence (Naninck e al., 2011), and so should be included in
s ess-p e en ion esea ch; ii) ocusing on males o p ac ical scien i ic
easons has his o ically esul ed in gende inequi ies in heal h and
medical knowledge, and iii) limi ing ec ui men o a single sex g oup
would ha e impac ed ou ec ui men po en ial gi en we en olled only a
single school. We did no ask emales o epo hei mens ual s a us o
use o ho monal con acep i es, as hey we e mino s and his would no
ha e been pe mi ed by ou ins i u ional e iew boa d.
Despi e a nea ze o e ec o sCo - eac i i y, he e ec sizes o
pe cei ed s ess (PSS) and non-speci ic psychological dis ess (K-10) (n
=34 o bo h) we e o meaning ul magni ude ( hough impo an ly hese
we e also no s a is ically signi ican ). P io esea ch sugges s highe -
in ensi y physical ac i i y may p oduce la ge e ec s on adolescen s’
men al heal h compa ed wi h lowe in ensi y physical ac i i y (Ahn &
Fedewa, 2011). Howe e , he e ec sizes o PSS and K-10 in he p esen
ial we e simila o bo h physical ac i i y g oups. Gi en he small
Figu e 3. Sali a y co isol esponse cu es o he T ie Social S ess Tes o G oups a pos - es No e. Shaded a ea ep esen s he s ess induc ion pe iod. Time is
gi en ela i e o s esso onse (i.e., 0 min). E o ba s ep esen s anda d e o o he mean.
Table 2
E ec s o physical ac i i y in e en ions on s ess- eac i i y and sel - epo ed men al heal h.
Ou comes Pos - es mean (95%CI) alues
a
LPA CON
b
MVPA CON
b
CON LPA MVPA Mean di e ence (95%
CI)
p d Mean di e ence (95%
CI)
p d
sCo
AUCc,d
5.73 (5.20, 6.26) 5.67 (5.17, 6.16) 5.74 (5.17, 6.32) −0.06 (−0.76, 0.64) 0.863 −0.08 0.01 (−0.80, 0.83) 0.974 0.02
sCo
Peakc
0.41 (−0.23,
1.05)
0.48 (−0.28,
1.23)
0.57 (−0.16,
1.30)
0.07 (−0.94, 1.07) 0.890 0.08 0.16 (−0.81, 1.13) 0.728 0.19
Pe cei ed s ess ul 60.8 (44.8, 76.8) 65.0 (47.5, 82.5) 52.9 (31.9, 73.8) 4.2 (−19.6, 27.9) 0.721 0.15 −8.0 (−34.3, 18.4) 0.539 −0.30
Pe cei ed
unpleasan
55.2 (38.8, 71.7) 59.6 (40.6, 78.5) 78.8 (57.5, 100) 4.4 (−21.0, 29.7) 0.725 0.16 23.6 (−3.4, 50.6) 0.084 0.86
Pe cei ed s ess
scale
17.8 (14.8, 20.8) 15.8 (12.3, 19.3) 15.1 (11.8, 18.4) −2.0 (−6.7, 2.6) 0.378 −0.38 −2.8 (−7.2, 1.7) 0.219 −0.52
Kessle -10 23.0 (20.2, 25.8) 20.3 (17.0, 23.6) 21.1 (18.0, 24.2) −2.7 (−7.1, 1.7) 0.222 −0.54 −1.9 (−6.1, 2.3) 0.357 −0.38
No e. AUC, a ea unde he cu e; CON, con ol g oup; CI, con idence in e als; LPA, ligh -in ensi y physical ac i i y g oup; MVPA, mode a e- o- igo ous in ensi y
physical ac i i y g oup; sCo , sali a y co isol.
a
Leas squa e mean (95%CI) alues adjus ed o baseline.
b
Mean di e ence be ween g oups adjus ed o baseline alues. Nega i e alues ep esen a ou able di e ences ela i e o CON.
c
Log- ans o med p io o analysis o accoun o skewness.
d
Adjus ed mean di e ence calcula ed ollowing mul iple impu a ion o accoun o missing da a. All o he ou comes based on comple e-case analysis.
J.J. Smi h e al.
Psychology o Spo & Exe cise 76 (2025) 102754
7
sample size and lack o s a is ical signi icance, in e ences ega ding
hese ou comes mus be ea ed wi h cau ion. This said, ou indings a e
consis en wi h a la ge body o li e a u e demons a ing eliable bene i s
o physical ac i i y on sel - epo ed men al heal h among you h (Biddle
e al., 2019).
Su p isingly, he la ges e ec size obse ed was o subjec i e-
eac i i y, wi h pa icipan a ings o he TSST-G as ‘unpleasan ’
a ou ing CON o e MVPA (d =0.86, p =.084). While no s a is ically
signi ican , his inding is no able gi en he e ec size is la ge, in he
opposi e di ec ion o ou hypo hesis, and inconsis en wi h he be ween-
g oup di e ence o a ings o he TSST-G as ‘s ess ul’ (which a ou ed
MVPA o e CON; d = − 0.30, p =.539). Explaining his inconsis ency is
challenging, bu one possibili y is ha hese indings a e ac ually in line
wi h he CSA. Fo example, i is possible ha pa icipa ion in MVPA
migh ‘shi ’ indi iduals om expe iencing a mo e a e si e a ec i e
s a e (i.e., ‘s ess ul’) in esponse o a s esso , o a less a e si e (albei
s ill nega i e) a ec i e s a e (i.e., ‘unpleasan ’). In his sense, g ea e
pe cep ions o he s esso as ‘unpleasan ’ could ac ually be iewed as a
posi i e inding, gi en hey a e coupled wi h lowe pe cep ions o he
expe ience as ‘s ess ul’ ( hough no he same deg ee). This explana ion
is specula i e, and i may be ha hese di e ences a e simply chance
e ec s ha would no ep oduce in a subsequen ial. S ill, his p e-
limina y esul aises an in e es ing ques ion ele an o in e p e ing
g oup di e ences in subjec i e- eac i i y o he TSST-G, ha would be
good o explo e u he in a p ope ly powe ed ial.
S eng hs o he p esen s udy include he indi idually andomised
RCT design, and use o a obus bioma ke o s ess collec ed in esponse
o he mos highly ega ded psychosocial s ess-induc ion pa adigm, as
well as s ong deli e y ideli y. The use o an al e na i e s esso ask a
baseline is also a no able inno a ion ha o ou knowledge has no been
employed be o e. Addi ional s eng hs include con olling o po en ial
bias in he in e en ion design, wi h physical ac i i y sessions occu ing
on he same days and imes, in he same se ing, and wi h equi alen
exposu e o esea ch s a . Finally, he expe imen al manipula ion was
success ul, as demons a ed by clea di e ences be ween LPA and MVPA
o mean/peak session HR esponses collec ed o e e y pa icipan
ac oss all sessions deli e ed. The e a e also se e al impo an limi a-
ions, many o which ha e been discussed. These include he small
sample size, subop imal pa icipan e en ion o he p ima y ou come,
and poo pa icipan adhe ence wi h he physical ac i i y p og ams. In
addi ion, we did no collec da a on sleep, gene al physical ac i i y,
die a y beha iou s, o body composi ion, which ha e all been linked o
co isol le els in you h. While andomisa ion should p o ide ough
balance be ween ea men g oups on hese ac o s, he small sample
size means he e is a isk o imbalance be ween condi ions on po en ially
impo an con ounde s.
4.1. Implica ions o u u e esea ch
Despi e ou null esul s, he no el y o he p esen ial alongside
many obus ea u es o ou me hodology p o ide a use ul empla e o
o he s wo king on his esea ch ques ion, which we eel is in u gen need
o g ea e a en ion. To add ess he limi a ions o he p esen ial, u u e
esea ch migh conside he ollowing imp o emen s: (i) inc ease sam-
ple size by en olling s uden s om a la ge numbe o schools; (ii)
imp o e pa icipan adhe ence by p o iding exe cise sessions du ing
manda o y pe iods o he school day. This migh equi e subs an i e
p epa a o y wo k wi h school leade s o con ince hem o he ad an-
ages o his in e en ion when i migh come a he cos o exis ing
cu icula ime; (iii) inc ease he exe cise dose by ex ending he in e -
en ion o e a longe du a ion (and pe haps inc easing session e-
quency/du a ion). While de e mining he minimally e ec i e dose o
exe cise o suppo olde adolescen s ess emains impo an , an
in e en ion o a leas 8 weeks (wi h a weekly dose ≥60 min) may be
needed o s imula e adap a ions o HPA-axis unc ioning; (i ) conside
addi ional con ounde s in he andomisa ion p ocess o analysis, which
migh include sleep, physical ac i i y, body composi ion, and die a y
beha iou s; and ( ) while a poin o no el y/inno a ion in he p esen
ial ha we iew as a s eng h, he SECPT used a baseline did no
appea o p oduce as obus a change in pa icipan s’ co isol as ex-
pec ed (and less so han he TSST-G). Whe he his was limi ed o ou
s udy sample o is ep esen a i e o how his popula ion espond o he
SECPT emains unclea . Fu he esea ch examining he u ili y o he
SECPT as a s ess induc ion pa adigm o olde adolescen s would
he e o e be in o ma i e. Ha ing he abili y o adjus o baseline di -
e ences in co isol- eac i i y wi hou unde mining he e icacy i he
s ess-induc ion a he p ima y end-poin (due o habi ua ion om
epea ed exposu e) emains a ension and a challenge in his ield.
5. Conclusion
Due o subop imal pa icipan ec ui men , e en ion, and adhe -
ence, we we e unable o d aw i m conclusions on he in luence o
physical ac i i y in ensi y on adolescen s’ sCo - eac i i y. Impo an ly,
he lack o an e ec o sCo ma ke s does no indica e a lack o suppo
o CSA, which emains a po en ial explana ion o he o en- epo ed
associa ion be ween physical ac i i y and s ess. G oup di e ences o
sel - epo ed men al heal h we e also non-signi ican bu a ou ed
physical ac i i y condi ions and we e o meaning ul magni ude, which is
consis en wi h he ex an li e a u e. Thus, u he examina ion o hese
ou comes in a p ope ly powe ed ial is wa an ed. Unde s anding he
mechanisms unde pinning he e ec s o physical ac i i y on you h
men al heal h emains an impo an a ea o u u e esea ch. Elucida ing
hese mechanisms may aid he design o physical ac i i y ocused s ess-
managemen in e en ions o his p io i y g oup.
Funding
This p ojec was suppo ed by philan h opic unding adminis e ed
by he Hun e Medical Resea ch Ins i u e.
CRediT au ho ship con ibu ion s a emen
Jo dan J. Smi h: W i ing – e iew & edi ing, W i ing – o iginal
d a , Supe ision, Resou ces, P ojec adminis a ion, Me hodology,
In es iga ion, Funding acquisi ion, Fo mal analysis, Da a cu a ion,
Concep ualiza ion. Ma k R. Beauchamp: W i ing – e iew & edi ing,
Me hodology, Funding acquisi ion, Concep ualiza ion. Eli Pu e man:
W i ing – e iew & edi ing, Me hodology, Funding acquisi ion,
Concep ualiza ion. Angus A. Leahy: W i ing – e iew & edi ing, Re-
sou ces, P ojec adminis a ion, In es iga ion, Da a cu a ion. Sa ah R.
Valkenbo ghs: W i ing – e iew & edi ing, Me hodology, In es iga ion.
Le i Wade: W i ing – e iew & edi ing, In es iga ion. F ances Chen:
W i ing – e iew & edi ing, Me hodology. Da id R. Lubans: W i ing –
e iew & edi ing, Me hodology, In es iga ion, Funding acquisi ion,
Concep ualiza ion.
Decla a ion o compe ing in e es
The au ho s decla e ha hey ha e no known compe ing inancial
in e es s o pe sonal ela ionships ha could ha e appea ed o in luence
he wo k epo ed in his pape .
Da a a ailabili y
Da a will be made a ailable on eques .
Acknowledgemen s
The au ho s would like o hank he eache s and s uden s a he
s udy school o hei coope a ion and pa icipa ion, as well as he
Hun e Medical Resea ch Ins i u e (HMRI) and all communi y membe s
J.J. Smi h e al.
Psychology o Spo & Exe cise 76 (2025) 102754
8
