The Relationship Between Maximum Jump Performance and Force-time Variables of Block Landing Skill in Junior Elite Volleyball Players

Abstract

Purpose: Frequent and powerful jumps and landings in volleyball exert significant stresses on lower extremities which can be determinant of injury prevalence. This study aimed to investigate the possible correlation between Maximum Jump (MJ) performance and force-time variables of volleyball block landing. Methods: Thirty elite junior volleyball players (Mean±SD of age: 18.140±1.125 y, sports background: 4.390±0.957 y, and height: 197.100±3.161 cm) performed three block jumps, and best of trials was considered for further analysis. The study data were collected by the KISTLER force platform (1000 Hz). Force-time, velocity-time, and displacement-time were obtained using the Excel program. The Kolmogorov-Smirnov and Pearson correlation coefficient were used for assessing data normality and possible correlations between variables using SPSS v. 21 (P<0.05). Results: Peak vertical impact forces were reported in a range of 1.8-3.5 BW (F1, F2) during 27 to 83 ms of peak times (T1, T2). Significant positive correlations were obtained between temporal variables of time of peaks (T1, T2), the time elapsed between peaks (TP), and end of landing time (Tf). A significant negative correlation was found between F2 and T2 and a significant positive correlation between MJ performance with peak vertical forces (F1, F2). Conclusion: According to the findings, T1 has little impact on shock absorption. Coaches and volleyball players should consider the importance of soft landing through increasing T2, which decreases F2, not only for performance improvement but also for reducing injuries.