Match-Related Acute and Residual Changes of Hip-Adduction Strength in Youth Soccer Players

The aim of this study was to investigate the changes in isometric hip-adductor strength (ADD_iso) following official matches in youth soccer players. In this observational study, eighteen young soccer players (age: 18.03 ± 0.53 years; body mass: 69.03 ± 5.70 kg; body height: 1.75 ± 0.06 m) participated. ADD_iso and match external demands were measured using a hand-held dynamometer and foot-mounted inertial measurement units, respectively, during official matches (match 1, M1 and match 2, M2) at pre-match (Pre), post-match (Post), and 24 hours post (+24h). In M1, ADD_iso decreased significantly from Pre to Post (p = 0.003, ES = -1.14), then increased Post to +24h (p = 0.002, ES = 1.49). In M2, ADD_iso decreased significantly Pre to Post (p < 0.001, ES = -1.41) then increased Post to +24h (p < 0.001, ES = 2.39). Non-significant differences were found Pre to +24h for M1 (p = 1.00, ES = 0.09), while the M2 +24h time point was significantly higher than Pre (p = 0.039, ES = 0.83). Regarding external match demands, players performed significantly higher releases per min in M1 compared to M2 (p = 0.024, ES = 1.10); conversely, intense speed changes per min (accelerations and decelerations) were significantly higher in M2 (p = 0.050, ES = -0.93). ADD_iso decreased post-match on average between 12 and 22% in this sample of youth soccer players. The average reduction in strength was larger after M2 which may be explained by different external demands like more intense speed changes. Further research into different game intensities and their potential influence on hip-adduction strength seems relevant.