Lower limb muscle injuries: Risk factors and preventive strategies

Objectives. - Muscle injuries are common in sports that involve high-speed and explosive movements or rapid changes in direction. The objectives of this article are: (1) to examine the risk factors for the main lower limb muscle strain-type injuries (hamstrings, quadriceps, adductors and triceps surae); (2) to analyze the effectiveness of preventive strategies for muscle injuries. News. These last years, a significant number of prospective studies identified several risk factors for muscle injuries. The most important intrinsic risk factor, whatever the injury site, is a previous injury. Muscle imbalances and age specifically concern hamstring tears; dominance (kicking leg) predisposes to a quadriceps injury; muscle imbalances and a lack of flexibility concern adductors injury; age and a lack of flexibility are also risk factors for triceps surae injury. The lack of flexibility remains controversial in the literature. The main extrinsic risk factors are the type of sport, an insufficient warm-up, an unbalanced training load and sport during competition. Preventively, it appears essential to propose progressive high-intensity eccentric exercises and to correct potential muscle imbalances. Prospects and projects. - The role of some risk factors such as: a lack of flexibility (specifically for hamstring and quadriceps injury), fatigue or the moment of the season should be cleared. Stretching activities should be continued but scientific evidence of its effectiveness for muscle injury prevention still needs to be demonstrated. There is also a need of evidence-based recommendations for optimal stretching modalities (duration, type of stretching...). Further studies are required to confirm the preventive interest, for hamstring and quadriceps tears, of manual therapy and core stability. Conclusion. - A previous injury represents the most important risk factor for muscle injuries. Additionally, every muscle group of the lower limbs seems to present specific risk factors. Hamstring and quadriceps strain incidence may show a powerful decrease thanks to the implementation of preventive strategies such as high intensity eccentric exercises. (C) 2017 Elsevier Masson SAS. All rights reserved.