Injuries, specially muscle injuries, are a great concern in sports as they represent the main cause of interruption for athletes. Moreover, in the case of team sports such as football, these injuries do not just represent a limitation on the athletes’ performance, but they can negatively impact the whole team as a result of the reduced availability of injured players in the team’s tactical planning, and they can also affect the club’s economy (with an estimated average cost of €500,000 per player for each month of absence).¹ Thus, the average absence due to muscle injury is 16 days with an injury load (days of absence/hours of exposure) of 43 days per 1000 hours of sports training for football players in elite European teams.² Therefore, muscle injury prevention is key for elite teams.

The hands-on approach based on evidence, which consists in combining high-quality scientific evidence with hands-on experience, is considered a gold standard to optimize the results in high performance.³ Because of that, professional teams should combine scientific knowledge with the experience of coaches, doctors, the coaching staff, and the players to prevent injuries. Usually, professionals resort to strategies based on exercising to prevent muscle injuries.⁴ In 2015, Alan McCall and Gregory Dupont, among other experts, summarized the existing preventive exercises in scientific literature, concluding that the most commonly used strategies based on exercising included eccentric and balance/proprioception exercises, although the scientific evidence that supports these strategies was weak and little recommended.⁴ However, since McCall et al. published their work in 2015, research and the interest of professionals in injury prevention has increased in the past 5 years, so it is appropriate to update such work.

McCall et al. study update

Therefore, a new systematic review, in which FC Barcelona Medical Services have collaborated, has just been published. It assesses the effectiveness of strategies based on exercising to prevent muscle injury in elite athletes.⁵ In this new work, authors have found two systematic reviews with low risk of bias concluding that there is no high-level scientific evidence that supports the effectiveness of strategies based on exercising to prevent muscle injury in elite players. Although five randomized controlled trials (RCT) and seven non-randomized ones supported the effectiveness of eccentric exercise, proprioception and multi-component exercises in injury prevention programmes posed a high risk of bias. Finally, there was only one RCT with low risk of bias that supported conducting eccentric exercises to prevent groin problems. Ultimately, the results confirm that there is no solid scientific evidence that supports the role of strategies based on exercising to prevent muscle injury in elite athletes.⁵

The expert opinion

A recently published study collected the opinion of 21 experts from different fields (physical therapists, sports scientists, exercise physiologists and sport physicians) with more than 12 years of experience in elite football and academic knowledge.⁶ The experts agreed to conclude that exercises such as sprints and high-speed running are perceived as more effective to prevent muscle injury, followed by eccentric exercises. The day to perform sprints and high-speed running or eccentric exercises will depend on the proximity to the previous and following match. Furthermore, concentric, and isometric exercises, vertical and horizontal plyometric, coordination exercises, core, and dynamic flexibility, as well as stability exercises were also defined as “partially effective” to prevent muscle injury. However, they did not come to any conclusions regarding the scheduling of training variables, such as the number of sets or repetitions, as it will depend of the context.

Conclusions

Therefore, according to the experts’ opinion, strategies based on exercising to prevent muscle injury should be mainly focused on sprints, high-speed running and eccentric exercises, combined in a multidimensional programme together with other types of exercises that have shown some level of effectiveness. Similarly, experts agree that the context in which these exercises are performed is key. Also, scientific evidence does not seem to support the role of strategies based on exercising to prevent injuries. Nonetheless, it is worth mentioning that this does not mean these exercises are not important or effective, but, maybe, they have not been scientifically validated yet.

Javier Salvador

References:

1. Ekstrand J. Keeping your top players on the pitch: the key to football medicine at a professional level. Br J Sports Med. 2013;47(12):723-724.
2. Ekstrand J, Hägglund M, Waldén M. Epidemiology of muscle injuries in professional football (soccer). Am J Sports Med. 2011;39(6):1226-32.
3. Coutts AJ. Challenges in Developing Evidence-Based Practice in High-Performance Sport. Int J Sports Physiol Perform. 2017;12(6):717-718.
4. McCall A, Carling C, Davison M, Nedelec M, Le Gall F, Berthoin S, Dupont G. Injury risk factors, screening tests and preventative strategies: a systematic review of the evidence that underpins the perceptions and practices of 44 football (soccer) teams from various premier leagues. Br J Sports Med. 2015;49(9):583-9.
5. Fanchini M, Steendahl IB, Impellizzeri FM, Pruna R, Dupont G, Coutts AJ, Meyer T, McCall A. Exercise-Based Strategies to Prevent Muscle Injury in Elite Footballers: A Systematic Review and Best Evidence Synthesis. Sports Med. 2020;50(9):1653-1666.
6. McCall A, Pruna R, Van der Horst N, Dupont G, Buchheit M, Coutts AJ, Impellizzeri FM, Fanchini M; EFP-Group. Exercise-Based Strategies to Prevent Muscle Injury in Male Elite Footballers: An Expert-Led Delphi Survey of 21 Practitioners Belonging to 18 Teams from the Big-5 European Leagues. Sports Med. 2020;50(9):1667-1681.