On-field rehabilitation in football: Current knowledge, applications and future directions

Abstract

Injury reduction remains a hot topic in professional football due to the economic and competitive implications of time lost (1, 2). Current strategies to reduce injury burden involve either reducing primary injuries through prevention-based strategies or lowering the risk of secondary injuries when they occur. It appears that primary injury reduction strategies are largely effective (3, 4), and might have supported reduced incidence across the past two decades (5, 6). Strategies concerning re-injury risk, however, are less than optimal, particularly when concerning recurrent and/or high-grade muscle and ligament injuries (1, 5). Whilst return to play (RTP) rates for such injuries are high in elite football, players often return with heightened risk of re-injury and may experience lower performance levels, especially after severe injuries such as anterior cruciate ligament (ACL) ruptures (7–14). Injuries are thought to occur due to a complex web of determinants (15), with previous injury remaining one of the most reported risk factors (16). Re-injuries (i.e., to the same location) or subsequent injuries (i.e., in a different location) typically occur early in the RTP process, suggesting players might be returned too quickly for sufficient tissue healing, or they are inadequately prepared for RTP demands (6, 16–18). The role of previous injury as a risk factor for future injury can be mitigated through effective rehabilitation (19). As such, improving RTP practice and processes appears warranted to improve outcomes after certain injuries (e.g., high-grade muscle/severe ligament injuries). There is a lack of consensus on effective rehabilitation for such injuries, with current evidence suggesting that players should embark on a criterion-based process through a series of stages (20). These typically include early-, mid- and late-stage rehabilitation, followed by a RTP continuum, involving on-field rehabilitation (OFR), return to team training, return to competitive match-play and finally a return to performance (Figure 1) (21–26). Recently, there has been an increase in translational research published to support football medicine departments with their late-stage rehabilitation processes, specifically that of OFR (21, 22, 26, 27). OFR as a service is not new with numerous practitioners establishing unpublished frameworks before evidence-based practice and load monitoring technologies existed. Scientific developments however have facilitated two separate published frameworks for OFR, which use competency-based continua to provide evidential structures to support long-established practices (21, 22, 26). Despite improving clarity, such research is currently restricted to expert opinion and/or case studies. Although this is a complex topic with numerous inherent challenges, future research should attempt validation of such frameworks. Figure 1. A return to sport process involving a gradual transition from rehabilitation to performance training along a continuum of OFR, RTT, RTC, and RTPer. ORF, on-field rehabilitation; RTT, return to training; RTC, return to competition; RTPer, return to performance. Modified and re-printed with permission from Buckthorpe et al. (21). The purpose of this article is to (i) review injury incidence literature to assess the prevalence of re-injuries and postulate OFR as a potential tool to mitigate future risk, (ii) consider injury aetiology and the complexity of OFR, (iii) describe existing OFR frameworks, and (iv) offer future directions related to the development of OFR in professional football. Understanding injury occurrence, healing timeframes and RTP rates are vital when designing, implementing, and evaluating OFR frameworks. When injuries occur, they are often categorised based on their severity, or the potential for time loss. Most injuries are mild (≤7 days), and overall RTP rates from all injuries are high, however those returning from severe injuries (>28 days) such as ACL ruptures often face long absence, elevated re-injury risk and reduced performance levels (1, 9). Overall, injuries have reduced by ~3% per year over the past 18 years, with muscle injury rates remaining unchanged (5). Although this should be considered in the context of greater frequencies and intensities of matches nowadays, muscle injuries remain a concern given their susceptibility to re-injury (17, 28). Indeed, injuries involving musculature of the lower limbs remain notable (~15%) (1). Ekstrand et al. (1) reported ACL re-injury rates at 6.6%, which is in-keeping with others (29), but less than the 18% reported by Della Villa et al. (9). However, it is perhaps severity and not incidence which is of concern for ACL injuries, with a mean absence of 205 days (1). Although, re-injury rates were low in the study of Waldén et al. (29), five out of the nine re-ruptures occurred during the final phase of rehabilitation or before the first match, and all others were within the first 3 months after the first match. The timing of these re-injuries suggests an increased risk during on-field activities and reinforces the importance of effective OFR frameworks. All injuries are related to an overload of some type, whether they involve trauma (i.e., contact), mechanical failure (i.e., non-contact) or a combination of both (i.e., indirect contact) (30, 31). They occur when the stress and/or strain on the body tissue exceeds the maximal strength or failure strain of that tissue (32). Injury prevention models have traditionally been based on a reductionist view (15, 33) that simplifies multifaceted components into units, attempting to identify relationships and sequence events (e.g., isolating the mechanism, site, type, and treatment of injury) (34, 35). In reality, injury involves complex interactions between numerous factors, and so seemingly comparable situations may yield different outcomes (15). Contributing factors might include any combination of neural...