HAMSTRING INJURIES

The hamstrings are a group of 4 muscles, which act to cause knee flexion and hip extension. Since the hamstrings cross both the hip and knee joints, their bi-arthrodial nature means they are subjected to greater loads, and thus may be more prone to injury. In fact, hamstring strains are the most common injuries sustained by sports people and are often serious - leading to long rehabilitation times. Athletes who suffer a hamstring injury also develop a distinct proneness to reinjury, with current literature suggesting a recurrence rate of up to 33% - emphasising the necessity for proper rehabilitation (3).

Typically, there are two mechanisms that lead to hamstring strains. High speed running, generally resulting in a strain of the biceps femoris muscle, and stretching motions carried out through an extreme range of motion (such as kicking), which tend to cause strains of the medial hamstring musculature. Symptoms of an acute hamstring strain may reduce within the first week post injury, leading to patients feeling as though they are ready to return to play. This is a dangerous period, as the integrity of the muscle is still not recovered, and the patient is at a great risk of doing further damage. Other injuries may also occur in the hamstrings, such as tendon issues, which often require an even greater period of rehabilitation.

Athletes may be more at risk of developing hamstring injuries if there is a strength imbalance, weakness in the hamstring musculature (particularly eccentrically), or experience a sudden increase in sprinting demands. Poor lumbopelvic control, reduced activity of the gluteal muscles, and an anterior pelvic tilt may increase the likelihood of hamstring injury occurrence in an athlete. The hamstrings play an important role during high speed running, as they act antagonistically to control the motion of the femur on the tibia as the quads produce anterior shear forces.

Rehabilitation of a hamstring strain can start very early following an acute strain and the sooner a progressive strength and range of motion programme is established the better. Rehabbing with some element of pain has been shown to result in a faster return to play than pain free rehab so don’t fear some mild discomfort during rehab (1). In the latter stages of rehab it is important to focus on increasing eccentric strength of the hamstring and gradually expose the hamstring to varying intensities of running before considering a return to play. The Nordic hamstring curl exercise programme has been shown to reduce the risk of hamstring injury in athletes and is an excellent exercise to include as part of any hamstring injury prevention programme (2).