Comparative effects of four back squat prescription models on explosive performance and sprint outcomes in resistance-trained men

Purpose To compare the effects of maximum intended velocity (MIV), velocity-loss threshold (VLT), target velocity zone combined with velocity-loss threshold (TVZ+VLT), and traditional percentage-based training (PBT) on explosive performance and sprint outcomes in resistance-trained men. Methods Fifty-two resistance-trained male athletes were randomly assigned to one of four groups and completed 12 supervised back squat sessions over 4 weeks. Primary outcomes were countermovement jump (CMJ) height, 0–30 m sprint time, and isometric mid-thigh pull rate of force development (IMTP RFD). Secondary outcomes included CMJ peak force and peak power, 0–10 m sprint time, IMTP peak force, relative IMTP peak force, and dynamic strength index (DSI). Results Significant baseline-adjusted group effects were retained after Holm correction for CMJ height (F = 7.50, P = .001, ηp² = .324) and 0–30 m sprint time (F = 4.77, P = .011, ηp² = .233). MIV and TVZ+VLT produced greater improvements in CMJ height than PBT, and TVZ+VLT produced a greater improvement in 0–30 m sprint time than PBT. Corrected group effects were also observed for CMJ peak power and DSI, whereas IMTP RFD and IMTP peak force did not show prescription-specific differences. Conclusions MIV and TVZ+VLT prescription packages were associated with more favorable short-term changes in selected explosive-performance and sprint-related outcomes than PBT. However, because the interventions differed in velocity zone, relative intensity, movement intent, feedback provision, and velocity-loss termination, and because session-level realized dose data were not retained, these findings should be interpreted as package-level effects rather than evidence for the independent superiority of any isolated VBT component.