How Much is Enough in Rehabilitation? High Running Workloads Following Lower Limb Muscle Injury Delay Return to Play but Protect Against Subsequent Injury

Stares, J., Dawson, B., Peeling, P., Drew, M., Heasman, J., Rogalski, B., Colby, M.

Examine the influence of rehabilitation training loads on return to play (RTP) time and subsequent injury in elite Australian footballers.

Design:
Prospective cohort study.

Methods:
Internal (sessional rating of perceived exertion: sRPE) and external (distance, sprint distance) workload and lower limb non-contact muscle injury data were collected from 58 players over 5 seasons. Rehabilitation periods were analyzed for running workloads, and time spent in 3 rehabilitation stages (1: off-legs training, 2: non-football running, 3: group football training) was calculated. Multi-level survival analyses with random effects accounting for player and season were performed. Hazard ratios (HR) and 95% confidence intervals (CI) for each variable were produced for RTP time and time to subsequent injury.

Results:
Of 85 lower limb muscle injuries, 70 were rehabilitated to RTP, with 30 cases of subsequent injury recorded (recurrence rate = 11.8%, new site injury rate = 31.4%). Completion of high rehabilitation workloads delayed RTP (distance: >49775m [reference: 34613-49775m]: HR 0.12, 95%CI 0.04-0.36, sRPE: >1266AU [reference: 852-1266AU]: HR 0.09, 95%CI 0.03-0.32). Return to running within 4 days increased subsequent injury risk (3-4 days [reference: 5-6 days]: HR 25.88, 95%CI 2.06-324.4). Attaining moderate-high sprint distance (427-710m) was protective against subsequent injury (154-426m: [reference: 427-710m]: HR 37.41, 95%CI 2.70-518.64).

Conclusion:
Training load monitoring can inform player rehabilitation programs. Higher rehabilitation training loads delayed RTP; however, moderate-high sprint running loads can protect against subsequent injury. Shared-decision making regarding RTP should include accumulated training loads and consider the trade-off between expedited RTP and lower subsequent injury risk.

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