Background Several examinations have demonstrated differences in anthropometry, jump performance, and strength variables between developmental and elite level volleyball players. However, within the elite level of play, the magnitude of change that can occur with training is unclear.

Objective To examine the anthropometric, vertical jump, and strength quality changes over 2 years in a group of national team volleyball players.

Design Longitudinal analysis with pre and post measurements spanning a 2 year time period.

Setting A male national volleyball team, involving professional players free of injury.

Participants 15 national team volleyball players (22.0±3.1 years, 1.98±0.09 m, 90.8±9.9 kg) began and completed this study. Participants had all played international matches prior to the examination time period, and continued to do so during the international season, while also playing for their professional club, through the 2 year duration of the study.

Interventions During professional seasons, match play volume varied depending on club, with training time typically involving four to seven court and two strength sessions per week. During international seasons, participants typically engaged in seven to nine court and two to four strength sessions per week, with match involvement ranging from 15 to 40 per season. Anthropometry (stature, mass, and Σ7 skin-folds, vertical jump measures (counter-movement vertical jump; depth-jump from 0.35 m DJ; spike-jump SPJ), speed-strength (body-weight jump squat, JSBW) and ballistic-strength (jump squat+50% body-weight, JS50) measures were tested prior to and at the conclusion of the investigation period.

Results Significant (p<0.05) improvements were observed in Σ7 skin-folds, DJ, SPJ, and JS50 performance, with large magnitude changes (Cohen's d>0.70) in the Σ7 skin-folds reduction, and increased jump height for the JS50.

Conclusions Large improvements in DJ, SPJ, and ballistic strength performance, as well as reductions in fat-mass, can be achieved in senior male national team volleyball players.