@Article{Bastias2026,
journal="Biology of Sport",
issn="0860-021X",
year="2026",
title="The influence of task constraints on football players’ performance: non-linear trends during goalkeeper training",
abstract=" In	the	realm	of	sports,	task	constraints	shape	players’	adaptation	processes	and	serve	as	crucial	 regulators	of	performance.	While	previous	studies	have	examined	the	influence	of	task	constraints	on	performance	 using	simple	linear	models,	potential	non-linear	relationships	remain	poorly	understood,	especially	in	highly	 complex	training	contexts	such	as	football	goalkeeping.	Our	study	involved	monitoring	the	performance	coefficients	 of	six	female	youth	goalkeepers	across	22 training	tasks,	which	were	characterized	by	eight	task	constraints	 encompassing	interactions	among	players	and	properties	of	the	training	environment.	We	used	Generalized	 Additive	Mixed	Models	(GAMMs)	to	examine	potential	non-linear	relationships	between	task	constraints	and	 goalkeeper	performance.	GAMMs	revealed	significant	non-linear	effects	for	several	task	constraints,	i.e.,	the	 number	of	players, field	dimensions, spatial	degrees	of	freedom and playing	time	(edf =	2.1–3.3,	P \< 0.001),	 explaining	20.8–30%	of	deviance.	Landscape	representativity	showed	a significant	overall	effect	on	performance	 (P =	0.003).	The	results	indicated	that	task	constraints	may	influence	goalkeepers’	performance	with	potential	 threshold-like	effects	and,	thus,	the	manipulation	of	task	constraints	during	training	might	be	partially	context dependent.	Overall,	the	results	advocated	for	a constraint-led	approach	that	facilitates	representative	training	 designs	high	in	player	interactions	to	devise	impactful	training	environments	for	players’	skill	development. ",
author="Bastias, Elliot
and Otte, Fabian
and Vaughan, James
and Hörtin, Dennis
and O’Sullivan, Mark",
pages="1579--1588",
doi="10.5114/biolsport.2026.163368",
url="http://dx.doi.org/10.5114/biolsport.2026.163368"
}