Optimizing warm-up efficiency: Impact of repetitions in straight leg raises on hip and knee flexibility in individuals with and without hamstring tightness

Abstract

BACKGROUND: Warm-up exercises are often recommended to enhance flexibility, reduce the risk of injury, and improve performance. However, the optimal number of warm-up repetitions remains unclear. Additionally, the previously suggested sit-and-reach test may not be suitable for efficiently stimulating the target muscles. OBJECTIVE: This study investigated the effects of a warm-up consisting of 15 straight leg raise (SLR) repetitions on hip and knee flexibility by comparing individuals with and without hamstring tightness (HT and NoHT, respectively). METHODS: Thirty healthy adults were classified as having HT or NoHT based on their SLR angle before warm-up. The participants performed 15 repetitions of the SLR as warm-up, followed by hip and knee flexibility tests. RESULTS: Warm-ups significantly improved hip and knee flexibility in both HT and NoHT groups. Improvements in flexibility were not significantly different between groups. The most notable increase in flexibility was observed between the sixth and ninth SLR trials. CONCLUSIONS: The clinical utility of a warm-up consisting of 15 SLR repetitions is supported by this study, as a substantial increase in hip flexibility was observed in all participants regardless of HT. In clinical settings, a maximum of 10 repetitions may be sufficient to achieve optimal results.