How to mitigate injury risk after return-to-play in elite football? Expert judgement meets data analytics

In elite football, injury risk is considerable, especially in the weeks after return-to-play (RTP). Consequently, optimal rehabilitation and well-informed decisions regarding the timepoint of RTP are crucial. Arguably, experiential knowledge as well as data-driven analyses may provide meaningful insights. This work leverages their synergies to identify and scrutinize promising options for reducing injury risk. A mixed-methods approach is implemented as sequential problem-solving pipeline. Semi-structured interviews were conducted with 14 experienced practitioners in elite European football. Areas of overlap in the interview data were identified by thematic analysis. Subsequently, media-based injury data was used to scrutinize expert judgement. In total 4 themes were identified concerning 1) time between index injury and RTP (rehab time), 2) rehabilitation strategy, 3) psychosocial factors, and 4) team structure. Most prominently, it was suspected that injury risk post-RTP would be lower with longer rehab times. Data analytics confirmed lower injury risk after longer rehab time (for the respective index injury diagnosis) if expressed per calendar day but not if expressed per unit of football exposure post-RTP. Hazard ratios for pooled episodes were 0.886 (0.834-0.937) for calendar time in days and 1.046 (1.005 - 1.087) for football exposure in weighted hours. Taken together, our results indicate options for improvement which are simple (at least logistically) and largely consistent with the literature. However, quantitative results don't provide direct support to the experts judgement that delaying RTP would reduce injury risk. Importantly, these findings are likely context specific and pertain only to elite players who sustained a subsequent injury.