Table 4. Descriptive statistics and ANCOVA for the DSI and its constituent variables.   Basic variables Control group mean ± SD Hedges g Intervention group mean ± SD Hedges g ANCOVA Pre-intervention Post-intervention Pre-intervention Post-intervention p-value η2 DSI 0.86 ± 0.14 0.93 ± 0.13 † 0.49 (-1.22-0.24) 0.91 ± 0.10 0.89 ± 0.14 -0.16 (-0.37-0.70) 0.052 0.087 CMJ max F (N) 2246 ± 295 2387 ± 327 0.44 (-1.16-0.29) 2309 ± 371 2310 ± 341 -0.00 (-0.54-0.53) 0.318 0.026 CMJ avg F (N) 1790 ± 231 1896 ± 209 0.47 (-1.22-0.28) 1827 ± 273 1840 ± 247 0.05 (-0.58-0.48) 0.181 0.046 IMTP rel F (N/kg) 28.94 ± 4.57 28.02 ± 3.87 -0.21 (-0.51-0.93) 28.97 ± 3.73 30.14 ± 4.39 § 0.28 (-0.82-0.25) 0.039 0.108 IMTP max F (N) 2653 ± 476 2597 ± 480 -0.11 (-0.60-0.83) 2529 ± 461 2636 ± 526 † 0.21 (-0.75-0.32) 0.054 0.094 * η2 = partial eta squared (analysis of covariance); CMJ = countermovement jump; F = force; max = maximal; avg = average; DSI = dynamic strength index; IMTP = isometric mid-thigh pull; rel = relative; SD = standard deviation; N = newtons; N/kg = newtons per kilogram † = indicates significant difference (p < 0.05) in paired t-test within group § = Indicates significant difference (p < 0.05) in post-intervention groups when using pretest score as a covariate.