JOINT ANGULAR POSITIONS THAT INFLUENCE VOLLEYBALL ATTACK HEIGHT IN MEN’S PLAYERS ChengTu Hsieh California State University, Chico, USA The aim of this study was to identify the angular position differences between high (HP) and low (LP) men’s volleyball performers at the instant of take-off and ball impact. Ten skilled collegiate men’s volleyball players were recruited from the university club team. All joint angular positions were obtained via 3D motion analysis. Results indicated that the HP players had greater normalized CoM (p < 0.004) and reach height (p < 0.004) at the instant of take-off and ball impact than the LP players, respectively. At the instant of take-off, HP players had a greater extension at hips, right knee, right elbow, left shoulder (flexion), and right shoulder (abduction) than LP players (p < 0.004). At the instant of ball impact, the HP players demonstrated greater right elbow extension, right ankle plantar flexion, right shoulder abduction, and smaller left shoulder flexion than the LP players (p < 0.004). KEYWORDS: 3D motion analysis, angular kinematics, jumping technique INTRODUCTION: In men’s volleyball, the attack is an essential skill to master which can determine the outcome of a match (Rodriguez-Ruiz et al., 2011; Ziv & Lidor, 2010). Attack height can provide a wide range of attack angles which results in the higher success rate of an attack (Abendroth-Smith & Kras, 1999). Anecdotally, attack height is one of the indicators used by coaches to recruit and assess young players and their training outcomes, respectively. Attack height is also considered to be essential data and is shared on the official volleyball game website (FIVB, 2018). Due to its importance, studies have focused on the enhancement of jumping ability from many different approaches to improve attack height such as plyometric training (e.g. Newton, Kraemer, & Häkkinen, 1999). However, this vast body of biomechanical studies quantifying jump height via the center of mass (CoM), from take-off to the peak, that is merely a part of overall attack height of this complex performance. Furthermore, there are only a hand full of studies examining the components of overall attack height (Matušov, Zapletalová, Duchoslav, & Hagara, 2013; Hsieh & Lamm, 2015; Vint & Hinrichs, 2004). When overall attack height is examined, jump height only represents the vertical displacement of CoM from the instant of take-off to the peak of projectile motion. It does not signify how high a player can reach. Based on a deterministic model, Vint and Hinrichs (2004) identified a total of four components of vertical displacement that represent overall attack height for elite women’s volleyball players. Those vertical displacement components are take-off height, flight height, reach height, and loss height. Vint and Hinrichs (2004) found that reach height (r = 0.70) and loss height (r = -0.47) were significantly associated with and accounted for 39.40% and -0.61% of overall ball contact height in female volleyball players, respectively. Take-off height accounted for 47.34% of overall ball contact height but had no significant relationship with ball contact height. More interestingly, jump height was not related to overall ball contact height and only accounted 14% of overall ball contact height. Hsieh and Lamm (2015) had similar findings with male volleyball players when all the components were normalized to body height. The only two components that were significantly associated with overall ball contact height were take-off (r = 0.80) and reach heights (r = 0.78), which accounted for 49% and 37% of the overall ball contact height, respectively. The jump height had no significant association with overall attack height and no difference between HP and LP players. It accounted for 14% of the ball contact height as Vint and Hinrichs’s study (2004) for female elite volleyball players. The ability of jumping has been considered as an essential element for volleyball attack performance for many studies (e.g. Abendroth-Smith & Kras, 1999). However, this is based on the assumption that body posture/segments are the same from take-off to the peak of the jump. In fact, it was found that junior female volleyball players had significantly higher variability of overall ball attack height than senior female volleyball players (Matušov et al., 2013). Although 348 37th International Society of Biomechanics in Sport Conference, Oxford, OH, United States, July 21-25, 2019 Published by NMU Commons, 2019