Purpose: Examine changes from 90-minutes of competitive match-play in countermovement jump (CMJ), creatine kinase (CK) and urine osmolality (Uosm) in elite football players over a season and their association to match external load.Methods: Eighteen footballers participated. CMJ, CK and Uosm were collected 24-h pre-match and 48-h post-match. Match-performance data was examined using Prozone®.Results: Post-match CK concentrations increased 49% (ES:0.66), while CMJ flight-time (FT), flight-time:contraction time ratio (FT:CT), take-off velocity (TV) and average power (AP) decreased 2.4-7.4% post-match (ES:0.39-0.63). CMJ height post-match reduced 4.2% (ES:0.35). CMJ FT and AP showed associations with high intensity distance covered (HID), high intensity number (HIN), explosive sprints (EXS) and medium intensity accelerations (r= -0.395 to -0.496). Changes in CMJ FT also displayed associations to total sprint distance (TSD), total sprint number (TSN) and medium intensity decelerations (r = -0.395-0.446). Increases in CMJ CT were associated with HIN (r=0.39), and CMJ AF with HIN, EXS and medium accelations/decelerations (r= -0.397 to 0.459) completed during the match.Conclusion: CMJ outputs from the push-off phase and countermovement phase were sensitive to change in neuromuscular fatigue. CK concentrations were sensitive to the match-play demands. This helps practitioners determine player readiness and has implications for individual recovery strategies.
Keywords: countermovement jump; creatine kinase; hydration; neuromuscular fatigue; performance monitoring; soccer.