@Article{Solleiro-Duran2026,
journal="Biology of Sport",
issn="0860-021X",
year="2026",
title="Does curvilinear sprint training with different radii improve 
multidirectional speed and sprint mechanics in youth soccer 
players?",
abstract="This	randomized	parallel-group	study	examined	the	effects	of	curvilinear	sprint	(CS)	training	with	different	radii	on	linear	sprint	(LS)	performance,	CS	ability,	change	of	direction	(COD),	and	horizontal	forcevelocity	(FV)	profile	in	youth	soccer	players.	Eighteen	male	youth	soccer	players	from	the	same	academy	were	randomly	assigned	to	a narrow	CS	group	(NCSG;	5.15 m radius)	or	a wide	CS	group	(WSCG;	11.15 m radius).	Both	groups	completed	12 CS	sessions	over	6 weeks	(2 sessions/week),	integrated	into	their	regular	team	training.	Pre-	and	post-intervention	assessments	included	LS	(5–30 m),	CS	tests	on	both	the	good	and	weak	sides	over	two	radii	(7.15 m and	9.15 m),	modified	505 COD	test,	and	sprint	mechanical	variables	from	the	FV	profile	(F0,	V0,	Pmax,	RFmax,	Drf).	No	significant	time	×	group	interactions	were	found	for	any	variable	(p > 0.05),	indicating	that	narrow	and	wide	CS	training	produced	similar	adaptations.	However,	within-group	analyses	revealed	significant	improvements	(p ≤ 0.05)	in	most	CS	tests	(except	for	the	good	side	on	9.15 m),	in	5	m	and	20	m	LS	times	and	COD	performance.	Additionally,	the	NCSG	and	WCSG	showed	small	to	moderate	significant	enhancements	(p ≤ 0.05)	in	Pmax	and	RFmax	after	the	training	intervention.	In	conclusion,	6 weeks	of	CS	training	improved	LS,	CS	ability,	COD	performance,	and	key	sprint	mechanical	outputs	in	youth	soccer	players.	These	findings	suggest	that	CS	training	is	a specific	and	effective	method	for	enhancing	multidirectional	speed	and	sprint	mechanics	in	this	population.",
author="Solleiro-Duran, David
and Suarez-Rial, Jose
and Rey, Ezequiel
and Baena-Raya, Andrés
and Lorenzo-Martínez, Miguel
and Filter, Alberto
and Padrón-Cabo, Alexis",
pages="829--838",
doi="10.5114/biolsport.2026.157996",
url="http://dx.doi.org/10.5114/biolsport.2026.157996"
}