Gastrocnemius medialis muscle architecture and its relationship with countermovement jump performance differ between male academy soccer players and control participants

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.