The Preventive Effect of the Nordic Hamstring Exercise on Hamstring Injuries in Amateur Soccer Players: A Randomized Controlled Trial

Abstract

Background Hamstring injuries are the most common muscle injuries in male amateur soccer. Eccentric strength of the hamstrings is recognized as an important modifiable risk factor, leading to the development of preventive exercises such as the Nordic Hamstring Exercise. Objective This study aims to investigate the preventive effect of the Nordic Hamstring Exercise on the incidence and severity of hamstring injuries in male amateur soccer players. Design Cluster-randomized controlled trial with soccer teams as the unit of cluster. Setting Dutch first class amateur field soccer. Participants Male amateur soccer players (mean age 24.5 years, SD 3.8 years) from 40 teams were allocated to intervention (n=309 players) or control group (n=310 players). Risk factor assessment The intervention group was instructed to perform 25 sessions of the Nordic Hamstring Exercise within a period of 13 weeks during the first months of 2013. Both the intervention group and control group performed regular soccer training and were followed for hamstring injury incidence and severity during the calendar year 2013. At baseline, personal characteristics (e.g. age, injury history, field position) were gathered from all participants via questionnaire. Main outcome measurements Primary outcomes are initial and recurrent hamstring injury incidence (number of hamstring injuries) and injury severity (number of days injured). Results Interim analysis after intervention (2 months follow-up) show a total of 2 hamstring injuries in intervention group vs 12 hamstring injuries in control group (χ2=7.5, P<.05). Regarding injury severity, no difference was found between intervention and control group (t=0.3, P=.77). Conclusions Preliminary analyses during the summer break show substantial hamstring injury incidence reduction by incorporating the Nordic Hamstring Exercise in regular training. With a total follow-up of 9 months, final analyses (survival analyses including the number of injuries per 1000 playing hours) will be performed in January 2014.

Impact of exercise selection on hamstring muscle activation

“…We have provided sEMG evidence to suggest that, during eccentric contractions, hip-extension exercise more selectively activates the lateral hamstrings while knee flexion-oriented exercises preferentially recruit the medial hamstrings. However, despite being the least selective activator of the BF, the Nordic still elicited higher levels of BF nEMG during eccentric actions than any other exercise which may help to explain how it confers HSI-preventive benefits 15 16 18. Our fMRI investigation largely confirmed our initial sEMG observations, showing that, relative to the semitendinosus, the BF LongHead was ∼4 times more active in hip extension than in the Nordic exercise.…”

“…The Nordic hamstring exercise is effective15 16 18 in reducing HSIs in soccer players as long as compliance is adequate 37 38. However, we11 and others22 have previously reported that the Nordic preferentially activates the semitendinosus, and this might be interpreted as evidence that the exercise is suboptimal to protection against running-related strain injury which predominantly effects the BF LongHead .…”

“…It is entirely possible that the Nordic confers injury-preventive benefits via an improved load-bearing capacity of the ST,39 however, in this study, we have provided EMG evidence which shows, despite the relatively selective activation of the semitendinosus, that the BF was still strongly activated during this exercise. Indeed, BF nEMG was higher during the Nordic than during the eccentric phase of any other exercise, and the evidence for this exercise's protective effects15 16 18 suggests that eccentric actions alone in a training programme are sufficient to make the hamstrings more resistant to strain injury. To some extent, these protective benefits might be mediated by the elongation of BF LongHead fascicles,40 which would be expected to improve the strength of this muscle at long lengths41 and reduce its susceptibility to exercise-induced damage 42.…”

Evidence-based hamstring injury prevention is not adopted by the majority of Champions League or Norwegian Premier League football teams: the Nordic Hamstring survey

“…In contrast, the efficacy of the NH programme on hamstring injury risk is well documented,1 28 and confirmed in a recent study on male Dutch amateur players documenting a 72% reduction in the risk for hamstring injuries 40. The NH exercise addresses the mechanism of injury, believed to be excessive maximal eccentric loading,23–25 as well as one key risk factor, eccentric strength.…”

The Effect of FIFA +11 Program on Functional Movement Screen Scores of Junior Soccer Players

“…Neuromuscular coordination exercises are used in the FMS rotary stability movement. Sideways bench item exercises and bench items to strengthen thigh muscles, which can help the participant to properly perform the FMS active straight leg raise movement (26,27).…”