The hamstrings are the muscles used for speed development, knee stabilisation and the quick deceleration needed for changing direction.

Injury to the hamstring occurs more in competition than during training, and a severely-injured hamstring may cut an athlete’s season short. Usually, a hamstring injury will be felt as a sharp pain in the back of the leg, which may cause the athlete to pull up. The injury may be caused by excessive lengthening of the hamstring while under tension, or a sudden contraction of the muscle after it has been actively lengthened.

Differences in strength between muscles can contribute to injuries. The quadriceps muscles may dominate the hamstrings, and this difference in strength between the quads and hamstring of the same leg can contribute to a hamstring injury, as can differences in strength between the left and right hamstrings. Poorly-trained or weak hamstrings may also cause many knee injuries.

Hamstring injuries can take time to rehabilitate, and can also re-occur. The injury is initially treated using “RICE”, followed by a treatment plan with may consist of electrotherapy, Graston technique, or muscle release techniques like stretching or trigger point therapy. Rehabilitation exercises and sport-specific skills are used to test the athlete’s performance before they return back to training for competition.

Stretching was often used for rehabilitation in the past, but as research into injuries has progressed, other techniques have been developed.

Eccentric exercises can help in reconditioning the hamstring muscles. These may be new to some athletes, who work concentrically on the muscle using equipment such as the hamstring leg curl machine in the gym. A frequently-used eccentric exercise is the Nordic exercise, but other exercises that target the hamstrings are leg swings (starting off straight then progressing to bent), straight-leg dead lifts, walking lunges at different speeds, and also sat back in a tug-of-war position while being pulled forward.

Eccentric training can cause soreness in the muscles trained, and this soreness may not be felt at the time of training but during the next day or even the day after that. For this reason, progression must be carefully monitored to prevent overtraining, which can be detrimental to the athlete and may delay further training.