The effect of including the Nordic Hamstring exercise on sprint and jump performance in athletes: protocol of a systematic review and meta-analyses

The Nordic Hamstring Exercise reduces hamstring strain injuries in football and other sports, but the exercise is not well adopted in practice. Barriers from practitioners include fear of performance decrements, due to lack of specificity of the exercise with high speed running. However, in theory, increased eccentric hamstring strength could transfer to faster sprinting due to higher horizontal force production. Studies on the effect of the Nordic Hamstring Exercise on performance have been conflicting and no synthesis of the evidence exists. We therefore pose the following question: does including the Nordic Hamstring exercise hamper sprint or jump performance in athletes? We will answer this question by performing a systematic review of the literature, critically appraise relevant studies, and GRADE the evidence across key outcomes and perform meta-analyses, meta-regression and subgroup analyses. In this protocol we outline the planned methods and procedures.