Preventive effect of eccentric training on acute hamstring injuries in men’s soccer: A cluster-randomized controlled trial
Petersen J, Thorborg K, Bachmann Nielsen M, Budtz-Jorgensen E, Holmich P (2011). Am J Sports Med, 39 (11), 2296-2303.
Hamstring muscle strains are very common in sports, especially soccer. The majority of injuries seem to occur when the hamstrings are contracting eccentrically, indicating a need for research on the efficacy of eccentric exercises on the prevention of hamstring injuries. This study used a cluster-randomized controlled trial to evaluate whether a 10-week training program using the Nordic hamstring exercise could lower the incidence of new and recurrent hamstring injuries. 54 male Dutch soccer teams were randomly assigned to either the 10-week intervention group (23 teams, 461 players) or a control (27 teams, 482 players) condition. The intervention was the Nordic hamstring exercise, a partner exercise in which one participant is supporting the ankles/lower legs of a second partner who is kneeling. The kneeling partner attempts a forward-falling motion (keeping hips/body rigid and in-line with legs) using his hamstring muscles to resist the fall. During team training sessions, coaches were asked to perform the exercise up to 3 times a week for a minimum of 10 weeks during a mid-season, non-competitive break (27 sessions). Hamstring injury (new and recurrent) and severity (days missed) were recorded for a year following the intervention. The control group reported 52 hamstring injuries (32 new and 20 recurrent) whereas the intervention group had a total of 15 injuries (12 new and 3 recurrent). Comparing the two groups, the Nordic hamstring intervention group significantly reduced total hamstring injury rates, as well as new and recurrent injuries. A numbers needed to treat analysis found that to prevent one hamstring injury (new or recurrent) 13 players need to perform the intervention. The intervention did not influence injury severity.
This study was the first to report the reduction of hamstring injury using the Nordic hamstring exercise in a cluster-randomized controlled trial study design. This simple, partner implemented eccentric exercise was found to reduce total hamstring injury rate by more than 60% and recurrent rate by approximately 85%. Overall, this study evaluated how integrating a quick eccentric exercise can help athletes who have sustained a hamstring injury reduce the risk of recurrent injury. As sports medicine professionals, we know the importance of including strengthening exercises into our rehabilitation programs for injured athletes. However, often times we feel we need the newest high-tech, expensive equipment and gadgets to accomplish our goals. This study clearly shows that, in the case of hamstring rehabilitation, this may not be true. Although this study did not evaluate the affect of the Nordic hamstring exercise in rehabilitation protocols specifically, it does show potential for the incorporation of this simple exercise into rehab. The Nordic hamstring exercise only requires a partner for support and can be performed almost anywhere (clinic, field, turf, etc). Not only can this exercise be done to prevent recurrent injury, sports medicine personnel can encourage coaches to implement this into their regular training programs because of the ease of implementation and short amount of time needed to complete the exercise. One of the weaknesses of this study is that it only included male soccer players. What are your thoughts on other sports performing this exercise, will it be as affective? Also, what about in females? As sports medicine professionals, is this an exercise you have incorporated into your hamstring rehabilitations? If no, would you consider it? If yes, do you feel it is as successful as this study’s results?
Written by: Lisa Chinn
Reviewed by: Jeffrey Driban
Petersen J, Thorborg K, Nielsen MB, Budtz-Jørgensen E, & Hölmich P (2011). Preventive effect of eccentric training on acute hamstring injuries in men’s soccer: a cluster-randomized controlled trial. The American Journal of Sports Medicine, 39 (11), 2296-303 PMID: 21825112