Comparative Effects of Sand- and Grass-Based Repeated-Sprint Training on Aerobic and Anaerobic Performance in Soccer Players

Table 3. Effects of six weeks of repeated-sprint training on aerobic capacity variables in collegiate soccer players (mean ± SD).

Variables	Groups	Pre-intervention	Post-intervention	Pre-Post (%)	Interaction effect	Hedges’ g (95%CI)
VO_2max (ml/kg/min)	SAND	54.5 ± 3.39	58.4 ± 4.23 ^a,b	7.3 ^b	F = 8.7; p < 0.01	1.72 (0.87, 2.57) Large↑
	GRASS	54.3 ± 3.42	58.2 ± 2.50 ^a,b	7.3 ^b		1.72 (0.87, 2.56) Large↑
	CON	54.0 ± 3.05	54.6 ± 2.87	1.1		0.26 (-0.47, 0.98) Small↑
AT (ml/kg/min)	SAND	40.8 ± 2.49	43.9 ± 2.92 ^a,b	7.6 ^b	F = 8.0; p < 0.01	1.82 (0.95, 2.68) Large↑
	GRASS	41.4 ± 2.93	43.7 ± 3.42 ^a,b	5.3 ^b		1.29 (0.50, 2.09) Large↑
	CON	42.4 ± 3.05	42.8 ± 4.11	0.8		0.20 (-0.52, 0.92) Trivial↑
RE (ml/kg/min)	SAND	46.4 ± 4.59	44.7 ± 4.48 ^a	-3.7	F = 2.0; p = 0.15	-0.97 (-1.74, -0.21) Moderate↓
	GRASS	46.8 ± 3.09	45.1 ± 3.29 ^a	-3.6		-0.97 (-1.74, -0.21) Moderate↓
	CON	47.1 ± 3.08	46.9 ± 3.12	-0.4		-0.11 (-0.83, 0.61) Trivial↓

^a Significantly different from pre-intervention (p < 0.05);^b Significantly different from CON (p < 0.05).