Between-Match Variability of Peak Power Output and Creatine Kinase Responses to Soccer Match-Play.

Post-match assessments of peak power output (PPO) during countermovement jumps and creatine kinase (CK) concentrations are common markers of recovery status in soccer players. Yet, the impact of soccer match-play on recovery in the 48 hours after competition is unclear, and the between-match variability of these responses has not been examined. Fourteen reserve team players from an English Premier League club were examined over 1-4 matches per player. Creatine kinase and PPO were measured before, 24, and 48 hours after each match. Data were analyzed with within-subjects linear mixed models. Compared with the prematch baseline, PPO was 237 ± 170 W and 98 ± 168 W lower at 24 and 48 hours, respectively (p ≤ 0.005) and CK was elevated (24 hours: 334.8 ± 107.2 µ·L(-1), 48 hours: 156.9 ± 121.0 µ·L(-1); both p ≤ 0.001) after match-play. These responses were consistent across the different matches and playing positions (p > 0.05). Within-subject correlations between PPO and CK were significant (r = -0.558; p ≤ 0.005). The between-match variability of PPO was 10.9, 11.0, and 9.9%, respectively at baseline, 24 and 48 hours, whereas for CK, the variability was 41.7, 30.0, and 34.3%, respectively. These findings highlight that more than 48 hours are needed to restore metabolic and performance perturbations after soccer match-play, and that CK demonstrates greater between-match variability than PPO. Such information is likely to be of interest to those responsible for the design of training schedules in the days after a match and sports scientists whose responsibilities include the monitoring of recovery status in soccer players.