Age and Within-Session Countermovement Jump Response in Professional Soccer Players

Chronological age may influence how professional soccer players respond to a standardized testing sequence, yet this has rarely been examined within a single session. This secondary analysis included 227 professional male outfield players who contributed data from 243 preseason testing sessions. Squat jump, countermovement jump, and arm-swing countermovement jump tests were performed before isokinetic knee-strength testing and a maximal treadmill cardiopulmonary test and were repeated after only 3 minutes of recovery. Linear mixed-effects models included time, mean-centered age, and their interaction, with random intercepts for player and testing sessions. Countermovement jump increased by 1.91 cm (95% confidence interval: 1.64–2.17; p<0.001), with a significant time×age interaction (B=0.078 cm y−1; 95% confidence interval: 0.028–0.129; p=0.002). A similar interaction was observed for arm-swing countermovement jump (B=0.080 cm y−1; p=0.007), whereas the squat jump estimate was smaller and statistically inconclusive (B=0.027 cm y−1; p=0.291). The countermovement jump interaction remained broadly consistent in post hoc analyses accounting for body fat, relative knee strength, maximal oxygen uptake, and baseline countermovement jump. Older players therefore showed a slightly larger countermovement jump improvement across this demanding sequence. Although the test position was not manipulated, these findings suggest that the placement of the countermovement jump within a testing battery should be kept consistent when repeated jump assessments are compared.