Effects of Chronic Static Stretching on Maximal Strength and Muscle Hypertrophy: A Systematic Review and Meta-Analysis with Meta-Regression

Sports Medicine - Open

Table 2 Calculated pooled effect sizes with 95% CIs, degrees of freedom, p-values for significance and heterogeneity

Parameter	Effect size	95% CI	p-value	Heterogeneity (τ²)
Maximum Strength overall	0.30*	0.14, 0.46	< 0.001	0.01
Maximum Strength < 15 min	0.21	-0.06, 0.44	0.06	0.02
Maximum Strength ≥ 15 min	0.45*	0.29, 0.62	< 0.001	0.0
Maximum Strength < 6w	0.16*	0.05, 0.26	0.006	0.0
Maximum Strength ≥ 6w	0.36*	0.13, 0.59	0.003	0.04
Maximum Strength < 5x	0.26*	0.14, 0.38	< 0.001	0.0
Maximum Strength ≥ 5x	0.32*	0.05, 0.6	0.025	0.04
Muscle Size overall	0.2*	0.008, 0.32	0.003	0.0
Muscle Size < 15 min	0.13	-0.05, 0.30	0.14	0.0
Muscle Size ≥ 15 min	0.28*	0.12, 0.44	0.005	0.0
Muscle Size < 6w	-0.05	-0.12, 0.031	0.13	0.0
Muscle Size ≥ 6w	0.26*	0.14, 0.37	< 0.001	0.0
Muscle Size < 5x	0.09	-0.15, 0.33	0.39	0.0
Muscle Size ≥ 5x	0.27*	0.13, 0.42	0.002	0.0

Abbreviations 95% CI = 95% Confidence interval, 6w = 6 weeks, 5x = 5 sessions per week, * = significant change