By Barbara Boughton
A new study of more than 500 hamstring injuries sustained by collegiate soccer players provides evidence that return to participation after these strains is influenced by factors other than an athlete’s strength and flexibility.
In the study, published in the Journal of Athletic Training in July, researchers from the University of Virginia (UVA) in Charlottesville found that the time needed to return to full participation was not affected by player gender. Yet other factors did make a difference—including the point in the season when the injury occurred, the level of competition, and the player’s position. The data in the study, regarding hamstring injuries sustained between 2004 and 2009, were derived from the National Collegiate Athletic Association Injury Surveillance system.
“We had evidence from a previous study that there was a difference between men and women collegiate soccer players in the occurrence of hamstring injuries—with more men than women affected by these strains,” said Kevin Cross, PhD, PT, ATC, a staff physical therapist and research coordinator at UVA-HealthSouth Rehabilitation Hospital and lead author of the study. “Yet we didn’t know what extrinsic factors affected return-to-play time among players.”
The results indicated that when return-to-play time was compared between male and female soccer players with either first-time or recurrent hamstring strains, there were no significant differences. Yet male players with first-time hamstring strains took longer to return when the strain occurred during competition (vs practice) or in-season/postseason (vs preseason), or if the player was a Division I athlete (vs Division II or III).
Male players with recurrent hamstring strains took longer to return if the injury was sustained during the season or the postseason rather than in the preseason. Among women with recurrent strains, more days were missed by forwards than by midfielders or defenders. There were no significant differences for return-to-play time among women with first-time hamstring injuries, even when injury timing, position, and level of competition were considered.
“The findings suggest that athletes are more likely to need a longer time to return to play when they are injured while playing in an open environment and not restricting their activity—during competition, for instance, as opposed to practice, which is more regimented,” Cross said.
Athletes who tend to run at higher intensities during play and are therefore more likely to fatigue during games—such as Division I male athletes and female forwards—were also more likely to need longer recovery times, he added.
Clinically, the findings suggest that training should be not only sport-specific, but also specific for a player’s position and style of play, Cross said. Training athletes for whom competition involves high intensity sprints should also aim to aerobically and anaerobically challenge athletes during practices and minimize fatigue before competition. These goals can be best accomplished with longer sprints (about 40 m) and an exercise-to-rest ratio of 1:6, Cross added.
Athletes should also be given sufficient time to recover after a hamstring injury and should be able to function well during high-intensity sprinting before returning to play, Cross said. One test that’s particularly useful in assessing whether an athlete is ready to return to play is the Yo-Yo intermittent recovery test level 2, which consists of two timed 20-m runs, he added.
“It’s very useful to have this information, because it gives us some data when we try to project return-to-play time,” said Jimmy Smuda, MA, LAT, CSCS, a Tampa, FL-based athletic trainer with the United States Soccer Federation. “It also points out the importance of fatigue in these injuries, so training should really taper off as you near competition. Although you want to ensure that the athlete has the appropriate level of training, you also don’t want to tax them too much prior to competition.”
Cross KM, Saliba SA, Conaway M, et al. Days to return to participation after a hamstrings strain among American collegiate soccer players. J Athl Train 2015;50(7):733-741.