No abstract

Training volume has been associated with jumper's knee in volleyball players, but jump variability among professionals has not been investigated and individual jump demands are unknown. The purpose of this study was to examine position-specific jump demands required for training and competition during a professional volleyball season and to investigate the individual variability associated with jump load. Jumps performed by 14 professional players during one season of training and competition were timestamped, individually assigned, and recorded for jump height. Jump counts, heights, and frequency were analyzed to determine the specific jump load performed by players at each position during training and match play. A total of 129 173 jumps were performed during 142 sessions (108 practices, 27 matches, 7 friendly matches). Setters performed the greatest volume of jumps (121 jumps/training session). Opposites performed more high-intensity jumps than their teammates (median season jump height: 69% of maximum). Substantial weekly jump count variability was observed, 18 of 28 weeks included at least one player with a twofold increase in jump load or a player returning to volleyball after performing no jumps the previous week. Additionally, each player had at least 1 week with a twofold increase in jumps. Jump demands are high in professional volleyball, and performance programs should be tailored to the match and training demands required at each position. Jump loads are highly variable-substantial week-to-week increases were observed for both the team and individual players. As a result, monitoring individual jump load seems necessary.

Use of a commercially available wearable device to monitor jump load with elite volleyball players has become common practice. The purpose of this study was to evaluate the validity and reliability of this device, the Vert, to count jumps and measure jump height with professional volleyball players. Jump count accuracy was determined by comparing jumps recorded by the device to jumps observed through systematic video analysis of three practice sessions and two league matches performed by a men's professional volleyball team. Jumps performed by 14 players were each coded for time and jump type and individually matched to device recorded jumps. Jump height validity of the device was examined against reference standards as participants performed countermovement jumps on a force plate and volleyball-specific jumps with a Vertec. The Vert device accurately counted 99.3% of the 3637 jumps performed during practice and match play. The device showed excellent jump height interdevice reliability for two devices placed in the same pouch during volleyball jumps (r = .99, 95% CI 0.98-0.99). The device had a minimum detectable change (MDC) of 9.7 cm and overestimated jump height by an average of 5.5 cm (95% CI 4.5-6.5) across all volleyball jumps. The Vert device demonstrates excellent accuracy counting volleyball-specific jumps during training and competition. While the device is not recommended to measure maximal jumping ability when precision is needed, it provides an acceptable measure of on-court jump height that can be used to monitor athlete jump load.