Relationships Between Gastrocnemius Medialis Muscle Architecture, Vertical Stiffness, and Vertical Jump Performance in Track and Field Athletes

Background and Objectives: Gastrocnemius medialis (GM) muscle architecture and vertical stiffness have been associated with vertical jump performance, but their relationships across jumping tasks with different stretch-shortening cycle (SSC) demands have not been well characterized. This exploratory study aimed to characterize the relationships of GM muscle architecture and Kvert with vertical jump performance in collegiate track and field athletes. Methods: Thirteen athletes (age: 21.62 ± 2.60 years; height: 1.82 ± 0.06 m; body mass: 74.72 ± 8.72 kg) completed squat jump (SJ), countermovement jump (CMJ), and 30-cm drop jump (DJ-30) tests. GM muscle thickness (MT), pennation angle (PA), and estimated fascicle length (FL) were assessed using ultrasonography, and vertical stiffness (Kvert) was calculated from the CMJ. Results: Pearson correlation analyses identified positive correlations between GM PA and SJ peak force (r = 0.66, p = 0.01) and CMJ peak force (r = 0.56, p = 0.04), peak power (r = 0.62, p = 0.02), and jump height (r = 0.55, p = 0.04), while GM MT was positively correlated with CMJ peak velocity (r = 0.56, p = 0.04) and relative peak power (r = 0.62, p = 0.02). Kvert was also positively correlated with CMJ relative peak force (r = 0.62, p = 0.02). In contrast, no GM muscle architecture variables were significantly correlated with DJ-30 performance. However, none of these correlations remained statistically significant after adjustment for multiple comparisons. Conclusions: The findings suggest that GM PA and MT may be more closely related to performance in jump tasks with no or slower SSC demands (SJ and CMJ) than to fast SSC tasks (DJ-30). These findings therefore provide preliminary information for further investigation of how different aspects of GM architecture relate to specific components of jumping performance, although confirmation in larger samples is still needed.