Table 3.

Measures of heterogeneity across study comparisons

Assessment	I2	χ2 significance	Prediction interval
Weightlifting group and control group comparisons
Strength	16%	0.270
CMJ	28%	0.230	− 0.52 to 1.84
SJ	9%	0.330	− 3.19 to 5.87
Speed	39%	0.190	− 5.12 to 6.44
CODS	73%	0.020	− 10.30 to 11.64
Weightlifting group and traditional resistance training comparisons
WL Performance	82%	0.000	− 3.86 to 6.58
Strength	67%	0.003	− 1.37 to 1.75
CMJ	89%	0.000	− 2.35 to 4.25
SJ	69%	0.010	− 2.14 to 2.86
Speed	90%	0.000	− 5.14 to 7.22
CODS	92%	0.360
Weightlifting training and plyometric training comparisons
Strength	77%	0.004	− 3.97 to 5.35
CMJ	0%	0.680	0.31
SJ	0%	0.790	0.34
Speed	0%	0.490	0.20
CODS	14%	0.310	− 3.80 to 4.14

CMJ countermovement jump, CODS change of direction speed, SJ squat jump, WL weightlifting