Background Lower-extremity strength profile can be used in injury prevention, conditioning and rehabilitation of volleyball players.

Objectives The goals were: (1) to describe the concentric and eccentric quadriceps (Q) and hamstrings (H) muscle function in volleyball players, (2) to evaluate the differences in Q and H strength, strength ratios and bilateral strength asymmetry among age groups, playing positions and playing levels, (3) to compare bilateral strength asymmetry in Q and H muscles in two different contraction modes.

Design Controlled laboratory study.

Setting Competitive elite level.

Participants and intervention 95 professional male volleyball players were tested on an isokinetic machine at 60°/sec to assess concentric and eccentric Q and H strength. We also calculated strength ratios and bilateral strength asymmetries.

Results Multivariate analysis of variances indicated significant main effect of playing level on relative PT (p=0.001) and strength ratios (p<0.05). International-level players had significantly (p<0.05) higher H strength and dynamic control ratio (DCR) of the right leg compared to the first and/or second national division players. There were no signs of bilateral strength asymmetry regardless of muscle group tested and contraction mode.

Conclusions Our results suggest that right H strength and DCR could be important for successful volleyball performance. Descriptive data about Q and H muscle function can be used as guidelines for coaches and therapists during training and rehabilitation of male volleyball players.