Acute effects of kettlebell swings with different loads on lower limb performance

This study examined the acute effects of kettlebell swings performed at different loads on lower limb performance. Eighteen male university physical education students completed a randomized repeated-measures design. Individual load–power profiling was used to determine each participant's highest mean power (HMP) load and a load corresponding to 60% of HMP. Across six sessions (≥ 72 h apart), participants completed a standardized warm-up, a pre-test (countermovement jump [CMJ], 20-m sprint, or 505 agility test), kettlebell swings at the prescribed load, a 4-min recovery period, and a post-test. Paired-samples t -tests were used to compare pre- to post-test changes ( α = 0.05). The 60% HMP condition significantly improved CMJ performance, accompanied by increases in leg stiffness, braking-end force, and rate of force development during both braking and propulsive phases, as well as reductions in braking and amortization times ( p < 0.05). Sprint performance over 5, 10, and 20 m, as well as 505 agility performance, were also significantly improved ( p < 0.05). In contrast, the HMP condition elicited no significant performance enhancements and was associated with reductions in selected concentric-phase CMJ variables. These findings indicate that kettlebell swings performed at 60% HMP can acutely enhance explosive power, sprint speed, and agility. In contrast, heavier loads may require longer recovery periods to dissipate fatigue and optimize subsequent performance outcomes.