The Association between Single-Leg Jumping and Volleyball Blocking Performance Asymmetries

Poster Presentation
Paper ID : 1379-SSRC
Authors
1Department of Sports Injuries and Biomechanics, Faculty of Sport Sciences and Health, University of Tehran, Tehran, Iran
2Faculty of Sport Sciences and Health, University of Mazandaran
Abstract
Introduction: Athlete's performance in competition is highly important. performance of athletes can be assessed by various indicators. Inter-limb asymmetry is perhaps one of the effective indicators of performance that has been widely studied. This index has been calculated and analyzed by various functional tests and through different mathematical equations. Limb dominance and frequent use of one side of the body has been introduced as one of the reasons for the emerge of asymmetry. Volleyball is a popular sport performed by a dominant side that many athletes around the world are participating in.
Purpose: The aim of this study was to investigate if Volleyball Blocking Height and Execution Time Asymmetries are more evident in group of professional female volleyball players with higher Inter-limb Asymmetries in Forward and Lateral jumps.
Method: The study sample was comprised of 29 professional female volleyball players (age: 22.37± 3.53 years, weights: 66.68± 10.05 kg, height: 174.31 ±6.04 cm, history of play: 7.25 ±3.04 years) playing in Division 1 and 2 National Leagues. Athletes performed three field tests including Single-Leg Forward Jump, Single-Leg Lateral Jump and Volleyball Blocking with Cross-Over steps to the right and left blocking zones. Blocking performance was analyzed by KINOVEA application and Blocking height was calculated from the flight time of the participants.
After calculation of Inter-limb asymmetries in forward and lateral jumps and volleyball blocking execution time and block jumping height asymmetries, normality tests were performed. Then, participants were divided into "symmetrical" and "asymmetrical" single-leg jumping groups, based on the common >10% threshold and each group's blocking height and execution time asymmetries were compared at the significance level of p<0.05.
Results: Results of analysis showed block jumping height asymmetries (pvalue = 0.023) and blocking execution time asymmetries (pvalue = 0.02) were significantly different between two "symmetrical" and "asymmetrical" single-leg jumping groups.
Conclusion: According to the results of the present and previous studies, it is recommended that coaches use proper assessment and exercises for reducing functional asymmetry in order to improve performance of volleyball athletes.
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