Influence of Ankle Joint Mobility on Stretch-Shortening Cycle Contribution in Vertical Jump Performance

The Stretch-Shortening Cycle (SSC) is a fundamental neuromuscular mechanism that enhances explosive performance by storing and releasing elastic energy, particularly through the Achilles tendon. While tendon stiffness and neuromuscular coordination are known to influence SSC efficiency, the role of ankle joint mobility in this context remains unclear. This study aimed to investigate the relationship between ankle dorsiflexion range of motion and SSC contribution during vertical jump performance in trained adults. Twenty-seven physically active participants (19 males, 8 females) were assessed for ankle dorsiflexion using the Leg Motion system and performed both Squat Jump (SJ) and Countermovement Jump (CMJ) on a force platform. SSC contribution was calculated as the difference between CMJ and SJ heights, expressed in both absolute (centimeters) and relative (percentage) terms. Participants were categorized into high and low mobility groups based on the median dorsiflexion value (13 cm). Statistical analyses, including Pearson correlation (r = -0.262, p = 0.186), linear regression (R2 = 0.069), and independent t-tests, showed no significant association between ankle mobility and SSC contribution. No meaningful performance differences were observed between the two groups in CMJ, SJ, or SSC metrics. These findings suggest that ankle dorsiflexion does not independently predict SSC utilization in vertical jumping among trained individuals. Other factors such as tendon stiffness, explosive strength, and neuromuscular coordination may play a more decisive role. Future research should include dynamic mobility assessments and more diverse populations to better understand the interplay of these variables.