Research question Does the Nordic hamstring exercise (NHE) prevent hamstring injuries when included as part of an injury prevention intervention?

Design Systematic review and meta-analysis.

Eligibility criteria for selecting studies We considered the population to be any athletes participating in any sporting activity, the intervention to be 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.

Analysis The effect of including the NHE in injury prevention programmes compared with controls on hamstring injuries was assessed in 15 studies that reported the incidence across different sports and age groups in both women and men.

Data sources MEDLINE via PubMed, CINAHL via Ebsco, and OpenGrey.

Results There is a reduction in the overall injury risk ratio of 0.49 (95% CI 0.32 to 0.74, p=0.0008) in favour of programmes including the NHE. Secondary analyses when pooling the eight randomised control studies demonstrated a small increase in the overall injury risk ratio 0.52 (95% CI 0.32 to 0.85, p=0.0008), still in favour of the NHE. Additionally, when studies with a high risk of bias were removed (n=8), there is an increase of 0.06 in the risk ratio to 0.55 (95% CI 0.34 to 0.89, p=0.006).

Conclusions Programmes that include the NHE reduce hamstring injuries by up to 51%. The NHE essentially halves the rate of hamstring injuries across multiple sports in different athletes.

Trial registration number PROSPERO CRD42018106150.