Muscle injuries sideline athletes

By Doug Haltom, M.D.

Muscle injuries commonly affect both the athlete and the general population, accounting for 10 to 15 percent of sports injuries.

Injury mechanisms include strain, contusion, laceration and delayed onset soreness. Acute muscle strains and contusions account for 90 percent of these injuries.

Sports that require sudden and abrupt changes in direction and speed have the highest incidence of these injuries. Soccer, a popular sport this time of year, is one of the main sports in which muscle strains are extremely common.

Skeletal muscle is a complex arrangement of contractile proteins that interact with each other to allow the muscle to shorten or lengthen – or contract. These contractions allow joint motion and facilitate locomotion. Explosive movements, such as pushing off during a sprint or changing direction in soccer, can place excessive stress on these muscle units.
Injuries usually occur during eccentric load of the muscle – when the muscle gets longer as it contracts.

The most susceptible muscles are the ones that cross two joints, such as the hamstring, which crosses the hip and knee on the back of the upper leg. Others include the quadriceps, from the hip to knee on the front of the upper leg, and the calf, from the knee to ankle on the back of the lower leg. The groin, or adductor thigh muscle, is also susceptible and a common site for muscular strains.

Upon injury, athletes usually report discomfort that is made worse with muscle contraction. They also may report a sudden pain or stabbing sensation.

Muscle injuries are classified according to their resulting impairment, and they are generally assigned a grade one, two or three.

A grade one strain is a minor injury that tears a few muscle fibers, which is associated with minimal swelling. Essentially, there is no loss of muscle strength or function.

A grade two strain is a moderate injury with more torn muscle fibers and associated with loss of muscle strength and function. A grade three injury is the most severe; the muscle is completely torn, and there is loss of muscle function during the injury period.

The vast majority of these injuries are partial thickness tears – grade one or two strains. Treatment principles consist of rest with a brief period of a few days of immobilization. This acts to limit swelling and allow the new granulation tissue – or repair tissue – to form and gain strength.

The period of immobility needs to be very brief as early movement of these muscles improves regeneration and ultimately strength. The use of NSAIDs – ibuprofen or naproxen – in the early acute phase of the injury has also been shown to be effective with no deleterious effects.

After this brief period, which should be less than one week, the athlete can progress back into a rehab program focusing on strengthening the muscle group. The athlete may return to play when he or she can stretch the injured muscle as much as the uninjured muscle on the opposite extremity with little to no pain.

The good news is the vast majority of athletes return to their prior level of function without surgery. The time to return to play ranges from two to three weeks to two to three months, depending on the severity or grade of the strain. Potential surgery is reserved for those cases in which the muscle is completely torn or the tendon is torn from its bony attachment.