Vertical jump development in elite adolescent volleyball players: Effects of sex and age

Background: Vertical jump is one of the most prevalent activities performed in volleyball. During adolescence, boys and girls undergo substantial changes in physiological and anthropometric characteristics that influence vertical jump performance. Objective: The purpose of this study was to examine and quantify sex and age-related differences in vertical jump performance assessed as vertical jumps height (VJH) and ground contact time (T-c) during repeated vertical jump tests within the Czech and Slovak population of elite adolescent volleyball players. Further aims were to compare the obtained results to non-athletic adolescent national normative data and investigate the relationship between basic anthropometric measures and VJH. Methods: The cross-sectional study was conducted on 203 females and 180 males from 13 to 19 years old. Statistical analysis of VJH differences between sex and age categories was performed using two-way ANOVA with Tukey's post hoc test. The relationship between basic anthropometric parameters and VJH were examined by Pearson's correlation analysis. Results: ANOVA showed statistically significant differences in VJH between males and females (p < .001) and across the age categories (p < .001). Males performed better than females in each age group and VJH increased along with age. For females VJH reached a plateau at the age of 14 and then stagnated. Male players have lower T-c than females (p < .05), although age did not show significant influence on T-c in either females or males (p > .05). Volleyball players have significantly higher VJH than non-athletes across all age categories and sex differences in volleyball players were smaller than the sex differences among non-athletic adolescents. A correlation analysis revealed only weak sex specific correlations of VJH with body height, body mass and BMI. Conclusions: The presented study showed significant sex differences in VJH between elite male and female volleyball players from the age of 15. VJH increases continually with increasing age in males. In females the effect of age on VJH was insignificant.