Abstract
The aims of this study were to investigate gastrocnemius medialis (GM) muscle properties in male academy soccer players (ASP) and age- and sex-matched control participants (CON); and to explore the relationships between GM characteristics and jump performance. Thirty-four participants (ASP, n = 22, age 18.8 ± 1.4 years, height 1.82 ± 0.08 m, mass 75.1 ± 5.9 kg; and CON, n = 12, 22.2 ± 2.9 years, 1.75 ± 0.05 m, 71.6 ± 7.4 kg) completed the following assessments: ultrasound measurements of GM anatomical cross-sectional area (ACSA), volume, muscle thickness (MT), fascicle pennation angle ( θ p ) and fascicle length ( L f ); isokinetic dynamometry measurements of isometric plantar flexion and dorsiflexion maximum voluntary torque; and unilateral and bilateral, vertical and horizontal, countermovement jumps (CMJ), and bilateral drop jumps on a force platform. θ p (17.4° ± 2.5° vs. 14.3° ± 1.2°, P < 0.001); unilateral horizontal CMJ peak power (30.14 ± 3.53 vs. 23.18 ± 3.72 W kg − 1 ); and projectile range during unilateral (104 ± 16 vs. 89 ± 12 cm, P = 0.006) and bilateral (140 ± 14 vs. 129 ± 14 cm, P = 0.041) horizontal CMJ were greater in ASP vs. CON. In ASP alone, L f correlated inversely with vertical CMJ performance but positively with horizontal CMJ performance ( R 2 ≥ 0.200, P ≤ 0.042). Conversely, θ p correlated positively with vertical CMJ performance but inversely with horizontal CMJ performance ( R 2 ≥ 0.194, P ≤ 0.044). In CON only, ACSA, MT, volume and L f all correlated inversely with vertical CMJ performance ( R 2 ≥ 0.366, P ≤ 0.037). The opposing θ p and L f correlations with vertical and horizontal CMJ jump performance in ASP suggest GM architecture influences CMJ performance in a direction-specific manner in this population, while the different correlation patterns between ASP and CON suggest that GM architecture contributes to CMJ performance differently in these two populations.