INVESTİGATİNG THE RELATİONSHİP BETWEEN LEG STİFFNESS, JUMPİNG PERFORMANCE AND IMPULSE İN MALE VOLLEYBALL PLAYERS

Abstract

Reactive strength index expresses the overall performance of neuromuscular conditioning in standardised jump tests such as the drop jump. It is worth noting that the number of studies investigating the relationship between the kinematic components of the drop jump, particularly important in volleyball spiking and blocking, is limited.   The relationship between leg stiffness, contact time and impulse variables was investigated in this study. Participants were randomly selected and the study was conducted in a single session. Participants underwent a standard warm-up protocol for 20 minutes and then performed a drop-jump from a 15 cm platform with one step forward.  Leg stiffness, contact time and impulse values were measured.  The data obtained were analysed using the IBM SPSS 26. Normality tests of the data were performed using Kolmogorov-Smirnov and Shapiro-Wilk tests. It was found that the impulse data were not normally distributed (p<0.05). Spearman rho correlation analysis was used to test the relationship. The significance level was accepted as α = 0.05. The results showed that there was a strong and negative relationship between leg stiffness and contact time ( r=-0.958, p<0.05). In light of the results of the study, it was observed that as leg stiffness increased, contact time decreased and had a positive effect on drop-jump performance. This study demonstrates the power transmission role of leg stiffness in jumping sports.  It is believed that this information will be of value to sports professionals who are working with male athletes.