Age- and gender-related differences in explosive leg muscle function with respect to jump tests used: a comparative study.

Background: Various methods and corresponding variables have been used to assess explosive leg strength, but less is known about the extent to which they vary across ages with respect to the jump test used. The interrelationship between jump variables obtained from different tests is also poorly understood. This study sought to determine how different methodological approaches to assessing jump performance manifest in differences between females and males from childhood to adulthood. In this context, we were also interested in the relationship between leg stiffness and the tested jump variables in different age periods.

Methods: A total of 447 female and male non-athletes practising sports at a recreational level were divided into three groups as middle and late childhood (7-12 years), early, middle and late adolescence (13-18 years) and emerging adulthood (19-24 years). They performed squat jump (SJ), countermovement jump (CMJ), drop jump (DJ) and 10-s repeated jumps (RJs). SJ and CMJ height (h), pre-stretch augmentation (PSA), eccentric utilization ratio (EUR), Δh (CMJ-SJ height), DJ and RJs reactive strength index (RSI), RJs take-off power, and leg stiffness were analysed.

Results: Jump variables increased with increasing age from childhood to adulthood in males, while in females they increased until adolescence, followed by a slight increase towards adulthood. In this regard, significant between-gender differences were found in RSI obtained during DJ and RJs from 11 to 12 years, and in SJ and CMJ height and RJs take-off power from 15 to 16 years. Relative leg stiffness was highly correlated with RSI obtained from DJ and RJs in adolescents (r = 0.875 and r = 0.872; both p < 0.01) and adults (r = 0.911 and r = 0.898; both p < 0.01), whereas there were only low correlations in children. Leg stiffness was also correlated with PSA in adolescents and adults (r = 0.588 and r = 0.576; both p < 0.05), but not in children.

Conclusion: Jump performance differs significantly between genders from early adolescence, depending on the test used. Relative leg stiffness is associated with reactive jump capacity in adolescents and adults, but to a lesser extent with musculotendinous elasticity during jumps.

Trial registration: This study was not prospectively registered because it did not report outcomes related to health care interventions using human participants.