Study on Hamstring Re-injury Prevention (SHARP): protocol for an international multicentre, randomised controlled trial

INTRODUCTION: Previous studies showed that the Nordic hamstring exercise (NHE) effectively prevents primary hamstring injury. However, no study investigated the secondary preventing effect of the NHE on hamstring reinjury. The primary purpose of this study is to investigate the effectiveness of the NHE for preventing hamstring reinjury after return to play (RTP) following a hamstring injury in football players. The secondary purpose is to determine the effect of the NHE on sprint and jump performance. METHODS AND ANALYSIS: This is an international multicentre, prospective, parallel-group randomised controlled trial study. Subjects include male or female football players aged 18–40 years and within 1 week of RTP following a hamstring injury will be randomised into Nordics or a control group. Subjects in both groups continue their regular football training, but the Nordics group will perform an additional NHE programme. An online questionnaire will be sent to the subjects in both groups once per week within the first 10 weeks, then continued at months 6, 9 and 12. In a (performance) substudy, we will evaluate the effect of the NHE on sprint and vertical jump performance at three time points (at the beginning of the study, after 10 weeks and 12 months of follow-up). The primary outcomes are the incidence of hamstring reinjury within 2 and 12 months. The secondary outcomes are sprint and jump performance, adherence to the programme, duration of reinjury and reinjury burden. ETHICS AND DISSEMINATION: This study is approved by the medical ethics committee of Amsterdam University Medical Center (UMC) in the Netherlands (METC 2021_117), Faculty of Medicine Universitas Gadjah Mada in Indonesia (KE/FK/1248/EC/2021), Norwegian School of Sport Sciences in Norway (number 216–2 70 122) and Denmark (ethical submission in process). The study’s findings will be disseminated in scientific peer-reviewed journals and presented at international conferences. TRIAL REGISTRATION NUMBER: NL9711.