การปรบตวเชงแรง-เวลาเฉพาะเจาะจงตอการฝกแบบพลยโอเมตรก และการฝกแบบตรงกนขามในนกกฬาวอลเลยบอล

This study aimed to investigate and compare the effects of plyometric training (PLY) and contrast training (CT), combined with routine volleyball practice, against a control group (CON) in 45 male collegiate volleyball players. To minimize baseline variability, participants (N = 45) were ranked according to their 0–5 m sprint times, organized into matched triplets, and randomly allocated in a 1:1:1 ratio to the Contrast Training (CT), Plyometric Training (PLY), or Control (CON) group (n = 15 per group). Countermovement jump (CMJ) biomechanical variables, including peak power, relative peak power, rate of force development (RFD), impulse, and jump height, were assessed using a force platform and analyzed using multivariate and repeated-measures ANOVA. The results showed significant improvements in CMJ force–time characteristics in both experimental groups compared with CON (p < .001), with no significant between-group differences at baseline before the intervention (p > .05). Further pairwise comparisons revealed distinct mechanical adaptation profiles between the training modalities. CT demonstrated significantly better outcomes than CON and outperformed PLY in selected late-phase variables, such as Peak RFD90, Relative Peak RFD90, and Gross Impulse300 (p < .05), alongside greater relative peak power and jump height. In contrast, during the initial phase of force development (0–30 ms), both PLY and CT significantly improved early-phase rapid force development, as reflected in Peak RFD30 and Relative Peak RFD30, compared with CON (p < .05), with no statistically significant differences between the two experimental groups (p > .05). In conclusion, both PLY and CT effectively improved jumping performance compared with routine volleyball practice alone, through distinct mechanical adaptation profiles across temporal phases. CT produced greater improvements in late-phase RFD and jump height, whereas both methods significantly improved early-phase rapid force development, with no significant differences between them. These findings highlight the practical application of force–time profiling to individualized training prescription