Muscle strength and power in young volleyball players: reference values and age group differences

To date, there is a notable lack of comprehensive normative datasets that focus on youth volleyball players, which limits coaches' and practitioners' ability to objectively interpret individual test results, monitor longitudinal development, and distinguish normal maturation from training-induced adaptations. The study aims to establish reference values for muscle strength and power in young volleyball players across various age groups, and to determine age group differences. The sample consisted of 3,337 boys and girls aged 10 to 18 years. For assessment of muscle strength and power, the Hand Grip Strength test (HGS), along with countermovement jump without arm swing (CMJ), was implemented. To determine age group differences, one-way MANOVA and ANOVA with a Bonferroni post-hoc test were applied. The study results revealed the presence of significant age group differences in muscle strength and power in young volleyball players, in both males (F = 24.70, p < 0.001, η² = 0.26) and females (F = 45.86, p < 0.001, η² = 0.11). A significant increase according to age was observed in all measured parameters. Coaches are encouraged to implement tests for assessing the muscle strength and power, and use these reference values and percentile range in order to track the growth and development of children and youth involved in volleyball, monitor the training process, and identify potential talents in volleyball from the aspect of muscle strength and power.