Risk factors for hamstring muscle injury in male elite football: medical expert experience and conclusions from 15 European Champions League clubs

Abstract

Objectives: To describe the perceived importance of suggested hamstring injury risk factors according to chief medical officers (CMOs) of European male professional football clubs. A secondary objective was to compare if these perceptions differed between teams with a lower-than-average hamstring injury burden and teams with a higher than average hamstring injury burden.

Methods: First, CMOs of 15 European professional male football clubs were asked to suggest risk factors for hamstring injury in their club. The perceived importance of the suggested risk factors was then rated by all participants on a 5-graded Likert scale. Participating teams were divided in two groups depending on their hamstring injury burden during the 2019/2020 and 2020/2021 seasons. The LOW group consisted of seven teams that had a lower than average hamstring injury burden. The HIGH group consisted of eight teams that had a higher-than-average hamstring injury burden.

Results: Twenty-one risk factors were suggested. The majority were extrinsic in nature, associated with coaching staff, team or club rather than players themselves. 'Lack of communication between medical staff and coaching staff' had the highest average importance (weighted average=3.7) followed by 'Lack of regular exposure to high-speed football during training sessions' (weighted average=3.6). The HIGH group perceived the player factors fatigue and wellness as more important than the LOW group.

Conclusion: According to CMOs recruited in this study, most risk factors for hamstring injuries are extrinsic and associated with the club and coaching staff, and not the players themselves.

Keywords: football; hamstring; injury; muscle damage/injuries; soccer.

Figure 1

For a fresh player who begins a game with peak action performance and normal muscle function that corresponds to the loads demanded by the game, the risk for hamstring injury is minimal. However, as the game proceeds the player’s performance may not match loads demanded by the game due to fatigue and the risk for hamstring injury increases.

Figure 2

A player with fatigue accumulation due to excessive training/too many matches/overloading but still has normal muscle function begins a game with peak action performance that does not match the loads demanded by the game, and the risk for hamstring injury is already increased at the beginning of the game. As the game proceeds, the mismatch between loads demanded by the game and the player’s performance increases due to increasing fatigue, and the risk for hamstring injury increases even more.

Figure 3

A fresh player with muscle dysfunction such as lack of eccentric strength, will begin a game with peak action performance that does not match the load demand of the game and thus has an increased risk for hamstring injury already at the beginning of the game. However, due to increasing fatigue as the game proceeds, the mismatch between loads demanded by the game and player performance increases with consequent increase in the risk for hamstring injury.

Figure 4

A player with fatigue accumulation and muscle dysfunction such as poor eccentric strength, will begin a game with a great mismatch between the performance and the loads demanded by the game, and the risk for hamstring injury is already high at the beginning of the game. As the game proceeds fatigue increases with an even greater mismatch between load demanded by the game and the player’s performance, and the risk for hamstring injury increases rapidly.