The preventive effect of the Nordic hamstring curl in amateur soccer players: the differences in hamstring injury incidence between subgroups at risk and optimization of tailored training programs

Abstract

Aim: Hamstring injuries are the most prevalent injuries in soccer, 12-16% of all injuries. Eccentric exercises are shown effective to reduce the hamstring injury incidence in a total population but no research on specific subgroups is done. The aim of this study was to determine the effect of the risk factors: age, hamstring flexibility, prior hamstring injury and the position in field on the hamstring injury incidence after an intervention program with the Nordic hamstring curl exercise (NHC) in male amateur soccer players. Methods: Male amateur soccer players, aged 18-40 years, participating in the Dutch "First Class" eligible. Information on age, prior hamstring injuries and playing position was collected. Hamstring flexibility was measured using the Sit-and-Reach Test. The intervention group followed a 13-week intervention with the NHC. Associations between subgroups "at risk" and "not at risk" were analyzed using Pearson’s chi square test. Results: 329 players were included in intervention group and 299 in the control group. During the year 2013, 22 hamstring injuries were reported. The intervention showed a significant effect for being at risk by playing position defender compared to being at risk in the control group of 0,031. No difference in Odds ratios (OR) of subgroups, age, hamstring flexibility, prior hamstring injury and playing position midfielder and attacker, "at risk" and "not at risk" in the intervention group were shown. Conclusion: Eccentric hamstring training using the NHC is effective in players at risk by playing position ‘defender’. Nordic hamstring curl exercises must be included in the training program of players with playing position defender for prevention from hamstring injuries. Clinical Relevance:

An overview of risk factors can give information on soccer players being "at risk" for hamstring injuries and help trainers and medical staff to develop a training program tailored to each individual player optimizing injury prevention.