Biomechanical Stress and Asymmetrical Loading: Comparing Unilateral Landings Across Volleyball Hitter Positions

Biomechanical Stress and Asymmetrical Loading: Comparing Unilateral Landings Across Volleyball Hitter Positions

Alvin Sherman Library

Jump-based movements in volleyball, particularly unilateral landings, generate substantial injury risk to the anterior cruciate ligament (ACL). These landings create asymmetrical ground reaction forces and patellar joint instability, with outside and right-side hitters most affected since they often land on a single leg after spiking. Prior studies show that unilateral landings produce higher peak forces and reduced knee flexion compared to bilateral landings, increasing biomechanical stress. Lead-limb dominance and player position further influence landing mechanics and loading patterns. Using VERT, a wearable sensor that records jump height, frequency, and landing impact, along with synchronized video analysis, this study compares landing forces and intensity between unilateral and bilateral movements among collegiate female volleyball hitters at Nova Southeastern University. For athletes with synchronized video data, landings were coded as unilateral or bilateral to assess differences in peak G-force, jump height, and intensity. For those without explicit landing-type data, VERT-derived metrics such as 15G+ landing percentage, total jump count, and mean intensity were analyzed to infer relative mechanical load. Results indicated that hitters demonstrating higher jump intensities and greater frequencies of 15G+ landings exhibited more asymmetrical loading and higher unilateral impact sizes, particularly among outside hitters. This revealed distinct position-specific profiles that may predispose certain athletes to greater ACL strain. Continued use of VERT technology in training may enhance early detection of asymmetrical forces and guide individualized, position-specific injury prevention strategies.