Match High-Speed Running Distances Are Often Suppressed After Return From Hamstring Strain Injury in Professional Footballers

Abstract

Background: High-speed running is commonly implicated in the genesis of hamstring injury. The success of hamstring injury management is typically quantified by the duration of time loss or reinjury rate. These metrics do not consider any loss in performance after returning to play from hamstring injury. It is not known to what extent high-speed running is altered on return to play after such injury.

Hypothesis: Match high-speed running distance will change after returning from hamstring injury.

Study design: Non-randomized cohort.

Level of evidence: Level 3.

Methods: Match high-speed running distance in highest level professional football (soccer, Rugby League, Rugby Union, and Australian Rules) were examined for a minimum of 5 games prior and subsequent to hamstring strain injury for individual differences using a linear regression models approach. A total of 22 injuries in 15 players were available for analysis.

Results: Preinjury cumulative high-speed running distances were strongly correlated for each individual (r² = 0.92-1.0; P < 0.0001). Pre- and postinjury high-speed running data were available for a median of 15 matches (range, 6-15). Variance from the preinjury high-speed running distance was significantly less (P = 0.0005) than the post injury values suggesting a suppression of high-speed running distance after returning from injury. On return to play, 7 of the 15 players showed a sustained absolute reduction in preinjury high-speed running distance, 7 showed no change, and 1 player (only) showed an increase. Analysis of subsequent (second and third injury) return to play showed no differences to return from the index injury.

Conclusion: Return to play was not associated with return to high-speed running performance for nearly half of the players examined, although the same number showed no difference. Persisting deficits in match high-speed running may exist for many players after hamstring strain injury.

Clinical relevance: Returning to play does not mean returning to (high-speed running) performance for nearly half of the high-level professional football players examined in this study. This suggests that successful return to play metrics should be expanded from simple time taken and recurrence to include performance.

Keywords: football; hamstring; performance; professional; return to sport; shared decision making.

Figure 1.

Inclusion flowchart.

Figure 2.

Variation in actual high-speed running distance (in meters) from predicted high-speed running distance for each individual prior and subsequent to hamstring strain injury. Each panel represents an individual player’s data, negative x-axis values represent games prior to the hamstring injury, positive values represent games after the injury. Where more than 1 injury occurred, the first injury data are presented in blue, and the second injury (reinjury) in red. Each data point represents a deviation from the predicted high-speed running distance for the individual player. Positive values mean the player ran greater distance at high speed, and negative values mean the player ran less on that game than the predicted amount given the player’s preinjury data. The available data pre- and postinjury were ranged from 6 to 15 (median 15 for each) and represents all matches that season before and after the injury.

Figure 3.

Cumulative high-speed running distance residuals by game for all injury instances. The y-axis represents the deviation from the predicted high-speed running distance for each individual. Note the relatively tightly clustered values preinjury suggesting little game-to-game variance in high-speed running distance confirming the assumption of little within-individual variability in high-speed running preinjury, and the much larger variation after injury. The group mean is represented by the dashed red line showing a typical suppression of approximately 1000 m in high-speed running postinjury, but note the wide variance in these data.