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 ADD_iso 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.