Table 3. Descriptive statistics (mean and standard deviation) for the IST, UCMJ, and KFS tests before and after the intervention period across the four groups.
UT (n = 16) BT (n = 16) UBT (n = 17) Control (n = 17) Comparisons between groups in pre and post evaluations
F | p-value | Effect size
IST left (N) Pre 1011.1 ± 50.6 991.8 ± 38.3 993.9 ± 50.6 995.2 ± 41.9 F = 0.602; p = 0.616; ηp2 = 0.028
Post 1122.3 ± 56.2 b,c,d,* 1021.5 ± 39.5 d,* 1053.6 ± 53.6 d,* 975.3 ± 41.1 * F = 26.992; p < 0.001; ηp2 = 0.566
ES 2.09 (1.58;2.60) 0.76 (0.56;0.96) 1.13 (0.93;1.33) 0.48 (0.28;0.68)
%dif +11.0 +3.0 +6.0 -2.0
IST right (N) Pre 1120.3 ± 59.5 1095.2 ± 69.9 1106.5 ± 76.1 1104.9 ± 60.6 F = 0.384; p = 0.765; ηp2 = 0.018
Post 1210.0 ± 64.2 b,d,* 1117.1 ± 71.3 * 1150.7 ± 79.1 * 1093.9 ± 60.0 * F = 8.701; p < 0.001; ηp2 = 0.296
ES 1.45 (1.09;1.81) 0.31 (00.05;0.66) 0.57 (0.21;0.93) 0.18 (00.18;0.54)
%dif +8.0 +2.0 +4.0 -1.0
IST asymmetry (%) Pre 3.24 ± 1.26 2.11 ± 1.24 3.37 ± 1.22 3.30 ± 1.37 F = 0.127; p = 0.944; ηp2 = 0.006
Post 2.39 ± 1.29 d,* 2.78 ± 1.27 * 2.75 ± 1.25 * 3.63 ± 1.37 * F = 2.735; p = 0.051; ηp2 =0.117
ES 0.66 (0.30;1.02) 0.53 (0.17;0.89) 0.50 (0.14;0.86) 0.24 (00.12;0.60)
%dif -26.2 +31.8 -18.4 +10.0
UCMJ left (N) Pre 691.6 ± 58.8 692.1 ± 50.4 687.2 ± 50.7 698.1 ± 56.3 F = 0.116; p = 0.950; ηp2 = 0.006
Post 767.7 ± 65.2 b,d,* 706.0 ± 51.4 * 714.7 ± 52.8 * 684.2 ± 55.2 * F = 6.448; p < 0.001; ηp2 = 0.238
ES 1.23 (0.87;1.59) 0.27 (00.09;0.66) 0.53 (0.17;0.89) 0.25 (00.11;0.62)
%dif +11.0 +2.0 +4.0 -2.0
UCMJ right (N) Pre 756.8 ± 71.4 762.8 ± 63.9 754.8 ± 61.5 775.8 ± 78.8 F = 0.316; p = 0.814; ηp2 = 0.015
Post 828.7 ± 78.2 d,* 785.7 ± 65.8 * 777.4 ± 63.4 * 756.4 ± 76.8 * F = 2.968; p = 0.039; ηp2 = 0.126
ES 0.96 (0.60;1.32) 0.35 (00.01;0.71) 0.36 (0.00;0.72) 0.25 (00.11;0.62)
%dif +9.5 +3.0 +3.0 -2.5
UCMJ asymmetry (%) Pre 2.83 ± 0.82 3.06 ± 1.11 2.95 ± 1.04 3.27 ± 1.16 F = 0.535; p = 0.660; ηp2 = 0.025
Post 2.39 ± 0.83 * 3.38 ± 1.12 * 2.62 ± 1.06 * 3.15 ± 1.16 * F = 3.049; p = 0.035; ηp2 = 0.129
ES 0.53 (0.17;0.89) 0.29 (00.07;0.65) 0.31 (00.05;0.67) 0.10 (00.26;0.46)
%dif -15.6 +10.5 -11.2 -3.7
UCMJ left (cm) Pre 12.9 ± 0.6 12.9 ± 0.5 12.9 ± 0.5 13.0 ± 0.6 F = 0.116; p = 0.951; ηp2 = 0.006
Post 16.7 ± 0.6 c,d,* 16.1 ± 0.5 * 16.1 ± 0.5 * 15.8 ± 0.6 * F =6.429; p < 0.001; ηp2 = 0.237
ES 6.33 (3.93;8.73) 6.4 (3.97;8.83) 6.4 (3.97;8.83) 4.67 (2.78;6.56)
%dif +29.5 +24.8 +24.8 +21.5
UCMJ right (cm) Pre 14.6 ± 0.7 14.6 ± 0.6 14.5 ± 0.6 14.8 ± 0.8 F = 0.322; p = 0.810; ηp2 = 0.015
Post 15.3 ± 0.8 d,* 14.9 ± 0.7 * 14.8 ± 0.6 * 14.6 ± 0.8 * F = 2.969; p = 0.039; ηp2 = 0.126
ES 0.93 (0.21;1.65) 0.46 (00.25;1.17) 0.50 (00.21;1.21) -0.25 (00.95;0.45)
%dif +4.8 +2.1 +2.1 -1.4
UCMJ asymmetry (%) Pre 3.8 ± 0.4 3.9 ± 0.6 3.9 ± 0.6 4.0 ± 0.6 F = 0.549; p = 0.650; ηp2 = 0.026
Post 2.8 ± 0.6 * 2.5 ± 0.6 * 2.8 ± 0.6 * 2.7 ± 0.7 * F = 0.891; p = 0.451; ηp2 = 0.041
ES -1.96 (12.80;21.12) -2.33 (23.23;31.43) -1.83 (12.65;21.01) -2.00 (22.84;21.16)
%dif -26.3 -35.9 -28.2 -32.5
KFS left (N) Pre 191.8 ± 61.8 210.3 ± 50.5 209.7 ± 30.8 191.9 ± 36.5 F = 0.852; p = 0.471; ηp2 = 0.040
Post 322.1 ± 103.2 b,d,* 246.0 ± 59.1 * 262.1 ± 38.6 d,* 192.1 ± 35.8 F = 11.394; p < 0.001; ηp2 = 0.355
ES 1.50 (1.14;1.86) 0.65 (0.29;1.01) 1.37 (1.01;1.73) 0.01 (00.35;0.37)
%dif +67.9 +16.9 +25.0 +0.1
KFS right (N) Pre 207.4 ± 65.0 226.6 ± 47.8 233.0 ± 43.9 210.8 ± 42.4 F = 0.997; p = 0.400; ηp2 = 0.046
Post 338.0 ± 105.9 b,d,* 269.7 ± 56.9 * 286.6 ± 53.9 d,* 217.5 ± 45.8 F = 8.507; p<0.001; ηp2 = 0.292
ES 1.46 (1.10;1.82) 0.82 (0.46;1.18) 1.09 (0.73;1.45) 0.15 (00.21;0.51)
%dif +63.0 +19.0 +23.0 +3.2
KFS asymmetry (%) Pre 2.82 ± 1.37 3.20 ± 1.32 3.72 ± 1.60 3.25 ± 1.31 F = 1.133; p = 0.343; ηp2 = 0.052
Post 2.17 ± 0.94 d,* 3.48 ± 1.78 3.45 ± 1.25 4.64 ± 2.15 * F = 6.540; p < 0.001; ηp2 = 0.240
ES 0.56 (0.20;0.92) 0.18 (00.18;0.54) 0.19 (00.17;0.55) 0.78 (0.42;1.14)
%dif -23.1 +8.8 -7.3 +42.8
UT: unilateral plyometric jump training; BT: bilateral plyometric jump training; UBT: combined unilateral and bilateral plyometric jump training; IST: unilateral isometric squat test; UCMJ: unilateral countermovement jump test; KFS: unilateral isometric knee flexor strength test; ES: Effect size comparing pre- and post-measurements using Cohen’s d presented in form of mean (95% confidence interval); %dif: Percentage difference between pre- and post-measurements;*significant differences within-group (p<0.05);b: significantly different from BT (p < 0.05);c: significantly different from UBT (p < 0.05);d: significantly different from control group (p < 0.05).