The acute effect of training on hip-adduction strength within a football microcycle

This exploratory study aimed to examine the changes to hip adduction strength within the football microcycle. The microcycle included the following training sessions: match day minus 4 (MD-4), MD-2 and MD-1. Twelve male youth football players were recruited (age: 17.11 ± 0.52 years; body mass: 72.63 ± 5.53 kg; height: 1.78 ± 0.05 m) and had their maximal isometric hip adduction strength (ADD_iso) measured before and immediately after each training session. Players wore foot‑mounted inertial measurement units (Playermaker) during each training session to quantify locomotor activities. A linear mixed model and one sample t test were used to assess ADDiso and percent changes, respectively. Statistical significance was set at ≤ 0.05. The group arrived at MD-1 with the lowest strength of the week, but finished the training with recovered ADD_iso, similar to all other pre‑match time points (MD‑4_pre, 3.04 Nmkg–1; MD-2_pre, 3.09 Nmkg^–1; MD-1_pre, 3.04 Nmkg^–1, p > 0.05). The group-level post-training percent changes to ADD_iso were: MD‑4, –4.00 ± 7.29%, p = 0.083; MD‑2, –3.76 ± 5.04%, p = 0.043; and MD-1, 7.43 ± 4.92%, p < 0.001. In summary, high-intensity training sessions with high‑speed running and change of direction actions were associated with reductions of hipadduction strength, while sessions with less high‑intensity locomotor demands while emphasising shooting actions were associated with a potentiating effect on ADD_iso. This is important considering the relationship between hip adduction strength and groin injury and pain.