Effect of Free Weights Versus Machine Based Resistance Training Along With Plyometrics on Vertical Jump Performance and Dynamic Balance Among Collegiate Volleyball Players

Background: Volleyball performance requires lower-limb strength, power, and dynamic balance due to repeated jumping and rapid directional changes. Resistance training combined with plyometrics is widely used to develop these qualities; however, comparisons of free-weight and machine-based resistance training within a non-linear periodization framework remain limited. Objective: To compare free-weight resistance training with plyometrics versus machine-based resistance training with plyometrics on vertical jump performance and dynamic balance in collegiate volleyball players. Methods: Thirty male collegiate volleyball players aged 18–23 years were purposively selected and allocated to Group A (free-weight training with plyometrics, n=15) or Group B (machine-based training with plyometrics, n=15). Both groups trained twice weekly for six weeks (50–60 minutes/session) using non-linear periodization alongside regular volleyball practice. Resistance loads were prescribed using baseline 1RM assessment and adjusted using repetitions-in-reserve (RIR). 1RM was reassessed at weeks 2 and 4 to guide progression. Vertical jump performance was assessed using the Sargent Jump Test and dynamic balance using the Y Balance Test before and after intervention. Results: Both groups showed significant pre-to-post improvements in vertical jump performance and dynamic balance (P<0.05). Group A demonstrated significantly greater improvements than Group B in vertical jump performance and anterior, posteromedial, and posterolateral Y Balance Test reach directions (P<0.05). Conclusion: Both training approaches improved jump performance and dynamic balance, with greater gains following free-weight resistance training combined with plyometrics.