BACKGROUND & OBJECTIVE:
The Nordic hamstring exercise (NHE) has received an enormous amount of attention in both the literature, and in clinical practice. Three large intervention studies (two randomized and one non-randomized) have shown that injuries can be reduced by approximately 70% by implementing the NHE in a team’s training regime.
Systematic reviews promise a high-quality, comprehensive summary of the research regarding an intervention, such as the NHE for preventing hamstring injuries. However, the omission of relevant studies in previous reviews might lead to a biased estimation of the effect of including the NHE in an injury prevention programme. Therefore, this systematic review carried out an inclusive, comprehensive systematic review and meta-analysis to answer one clinical question: If we include the Nordic hamstring exercise, will it reduce hamstring injuries?
Relevant articles were identified following a search of the electronic databases: Medline, CINAHL, and Opengrey. For this investigation, the population was any athletes participating in any sporting activity, the intervention to be the NHE or any programme that included the NHE, the comparison to be usual training or other prevention programmes which did not include the NHE, and the outcome to be the incidence or rate of hamstring injuries. Studies without a comparison or control group were not included, thereby excluding case series and case studies. Studies were not excluded based on gender, age, or level of competition. Assessment of methodological quality and risk of bias were performed, including additional sensitivity analyses of high-quality studies.
The initial database search yielded a total of 1590 potentially relevant studies. After review and selection criteria, 15 studies (8 randomized control trials and 7 cohort studies) were included. The pooled data for 8459 individuals including 525 hamstring injuries were