Principal Investigator: Scott D. Martin, MD
Introduction: Hamstring injuries are common among athletes. Considering the potentially prolonged recovery and high rate of recurrence, effective methods of prevention and risk factor management are of great interest.
Methods: A search of MEDLINE, CINAHL, Cochrane CENTRAL Register of Controlled Trials, and SPORTDiscus with manual screening of selected reference lists was performed.
Results: Of 2,602 articles, 108 randomized controlled trials were included. Eccentric training reduced the incidence of hamstring injury by 56.8%-70.0%. Concentric hamstring strength increased with eccentric, concentric, blood-flow restricted, whole body vibration, heavy back squat, FIFA 11+, and plyometric training methods, whereas eccentric strength benefitted from eccentric, concentric, and plyometric training. Static stretching produced greater flexibility gains than proprioceptive neuromuscular facilitation and dynamic stretching. Fascicle length increased with eccentric and sprint training and decreased with concentric training. Functional hamstrings:quadriceps (H:Q) ratio significantly improved with eccentric training. Eccentric training reduced limb strength asymmetry, while H:Q ratio and flexibility imbalances were normalized via resistance training and static stretching.
Conclusion: Eccentric strengthening reduces injury incidence and improves hamstring strength, fascicle length, H:Q ratio, and limb asymmetry, while stretching-based interventions can be implemented to improve flexibility. These results provide valuable insights to athletes, trainers, and coaches seeking to optimize hamstring training/prevent injury.