Hamstring Pull, Tear, or Strain

The hamstrings are an interconnected series of tendons and muscles located behind the knee that, for the purposes of sport training, are usually regarded as a single collective structure. The hamstrings begin with the prominent tendons located behind each knee that begin with their connection to the top of each of the fibula and tibia, the bones of the lower leg. These tendons attach to the powerful hamstring muscles, technically known as the posterior thigh muscles, which extend the entire length of the leg, attaching to the gluteal muscles at the top of the rear leg. The hamstrings are some of the largest muscles in the body, composed of the semimembranosis, the semitendonosis, and the biceps femoris.

A pull, a strain, or a tear are injuries caused to either muscles or tendons; each injury results from an over-stretching of the tissue in question, and the distinction between a pull and a strain, which are different terms used to describe the same mechanism, and a tear, is only a matter of degree. A sprain, which is occasionally misused in describing muscular or tendon injuries, is an occurrence involving a ligament and a skeletal joint.

Hamstring strains and tears result in circumstances where the hamstring is subjected to the stress caused by an explosive force, such as that through acceleration or a dramatic change in running speed. Sprinters and hurdlers who begin their races from a fixed position in the blocks, American football receivers who are stationary at their line of scrimmage, basketball players, and rugby wingers who are required to break to a position on the field to receive the ball are athletes that are most commonly subjected to hamstring injuries. Strains and tears in the hamstrings are also a risk in sports where any sort of explosive leg drive is required in the execution of the event, such as the shot put, javelin, hammer throw, and the high jump.

Managed correctly, a hamstring strain or tear may be restricted to a one-time occurrence. However, hamstring injuries often carry the additional descriptor, "nagging," the usual result of poor rehabilitation of an initial injury. While the great majority of hamstring strains and tears resolve without surgery, injury management requires care and prudence regarding a return to competition.

No matter what degree of severity results from a hamstring injury, the first aid applied must include the RICE method (rest/ice/compression/elevation). As the injury will involve an overstretching or a tear of the muscle or tendon fibers, there must be sufficient time away from competition and training to permit recovery. Injury recovery periods can often be a time of useful analysis of prior training methods that may have contributed to the injury, such as an imbalance between the strength of the hamstrings relative to that of the quadriceps. When these two muscle structures are imbalanced, the leg will often be misaligned, placing additional stresses on either the hamstring or the knee and the ligaments. Most hamstring conditions will benefit from a focused approach to stretching, both as part of daily routine, as well as the development of warm-up and cool-down programs to improve the flexibility of the entire hamstring.

In hot weather training and competition, the hamstring is particularly vulnerable to injury. The dehydration of the body that often occurs in hot weather will often reduce the supplies of various electrolytes—particularly sodium and potassium—which are responsible for the transmission of the signals regulating muscular activity in the central nervous system. This condition will frequently cause muscle cramping, a muscle dysfunction that can contribute to a hamstring injury due to the imbalance created by the cramped muscle.

The ratio between the weight of the upper body and that carried by the legs and directed through the hamstrings when the legs move is also a factor in the cause of hamstring injuries. In circumstances where a person gains significant weight due to the inactivity resulting from injury or illness, or when an athlete embarks on a significant upper body program, the hamstrings will be exposed to greater than accustomed stresses. In these circumstances, hamstring injuries are far more frequent.

Athlete working with team physiologist in stretching hamstring.

Hamstring surgery is almost exclusively reserved for the tear that is a complete rupture of the muscle or the tendon. Such procedures are usually successful from the perspective of the repair being completed and the athlete making a full physiological recovery. However, the nature of these injuries is such that surgical success is not measured by whether the incision is completed healed, but rather by the degree to which the athlete can return to full pre-injury flexibility and explosiveness in action. There is no guarantee that a completely torn hamstring can ever be rehabilitated to 100% strength and efficiency. There is also the related mental component that often applies to this type of injury; the athlete must be able to completely suppress any fear of recurrence if the injury is to be entirely conquered.

SEE ALSO Hamstring injuries; Musculoskeletal injuries; Thigh and upper leg injuries.