Morpho-Functional Characteristics Related to Lower limb Stiffness, Explosive Power, and Reactive Strength Index (RSI) in Female Volleyball Players: Individual Variability and Performance Implications

In volleyball, the ability to perform explosive vertical jumps is crucial for success in both offense and defense.The main factors determining jump height are lower limb stiffness, explosive power, and the Reactive Strength Index (RSI), which reflect neuromuscular efficiency, tendon elasticity, and the ability to generate force quickly.The aim of this study was to analyze lower limb stiffness, explosive power, and RSI in female volleyball players, as well as to assess individual differences and their implications for performance.The study included 18 elite female volleyball players.Anthropometric parameters recorded were height, body mass, and Body mass index (BMI).Lower limb stiffness and explosive power were measured using the Multiple Repeated Stiffness Jump Test (MRSJT) with the Globus Ergo Tester Jump System, through six consecutive maximal vertical jumps.Mean values, ranges, and coefficients of variation were analyzed, and Pearson correlations were used to examine relationships between anthropometric parameters and jump performance.The mean lower limb stiffness was 24.93 N/m, mean jump height was 31.37 cm, explosive power was 46.34 W/kg, and mean RSI was 2.66.Individual values showed considerable variation (stiffness 13.37-43.02N/m, jump height 26.63-36.48cm, explosive power 31.65-56.10W/kg, RSI 1.77-3.44.Players with higher RSI demonstrated an optimal synergy of stiffness, jump height, and explosive power.No statistically significant correlations were observed between jump performance and anthropometric parameters, suggesting that neuromuscular and technical factors have a greater influence.The study highlights the presence of individual differences in lower limb stiffness, explosive power, and RSI among elite female volleyball players.An individualized training approach focusing on explosive power the lower limbs and enhancing reactive strength is recommended.