Muscle strains are one of the most common injuries athletes suffer during training and competition. They can be potentially debilitating and lead to significant missed time from activity. Fortunately, there are steps athletes can take to prevent these injuries from occurring. If an injury is suffered, immediate and appropriate treatment can reduce missed time and aid an athlete’s rehabilitation.

Anatomy of a Strain

A muscle strain is a pull or tear of a muscle and its corresponding tendon. Tendons are rope-like connections between muscles and bones. When muscles contract, their tendons pull on bone, causing movement across joints. Although strains can occur at any location of the muscle or tendon, they frequently occur at the junction between them.
Muscles strains usually happen when, after a muscle is stretched or lengthened, it is forcibly contracted. This is called an eccentric contraction. Strains can also occur when the muscle is stretched beyond its limit. A muscle strain is usually noted by the onset of acute pain; occasionally an athlete will recall a snapping or popping sensation. Later, the injured area will be tender and sometimes swollen and bruised. In severe cases, a defect in the muscle may be palpable.
The most common locations for muscle strains are in the strong muscle groups of the hips and legs—the hip flexors, quadriceps, hamstrings and hip adductors. Together, they control movement across the hip and knee joints. The hip flexors and quadriceps are in the front of the hip and thigh, the hamstring muscles are behind the thigh, and the hip adductors are located in the groin and inside thigh. Due to the large amount of power these muscles generate, they are at particular risk for strains when used in high-speed activities like sprinting and jumping. Strains can also occur in other muscles, and common locations include the lower back, neck and shoulder.
Strains range in severity and are graded according to the degree of muscle tear. Grade 1 strains are overstretches of the muscle-tendon unit with microscopic tears. Grade 2 strains are partial tears of the muscle-tendon unit, which typically cause some loss of strength and movement. Grade 3 strains, the most severe, are a complete tear of the muscle-tendon unit. Avulsion injuries are complete tears of the tendon at its insertion onto bone.

Risk Factors

The strongest risk factor for suffering a muscle strain is a prior injury to that muscle. Other risk factors include a lack of flexibility, muscle weakness and fatigue, muscle imbalance, and an inadequate warm-up. Muscle imbalances occur when one muscle group is significantly stronger than its opposing muscle group. For example, the quadriceps and hamstrings work together when running. In many athletes, relative hamstring weakness puts this muscle at higher risk for strain when the leg is extended and makes contact with the ground.
Good flexibility and adequate muscular strength and endurance decrease an athlete’s risk for suffering muscle strains. But if a muscle is strained, it is important to rehabilitate the injury properly. Athletes trying to return to play too quickly put themselves at risk for recurrent injury.

Treatment

After suffering a muscle strain, start treatment with the RICE protocol. RICE stands for Rest, Ice, Compression and Elevation. Rest means taking a break from the activity that caused the injury. In severe muscle strains, crutches may be needed.  Ice should be applied frequently, every two to three hours, during the first several days after injury. In addition to ice, compression bandages such as ACE wraps can help reduce swelling. Elevating the injured area above the level of the heart can further decrease swelling.
To return to sports as quickly and safely as possible, proper rehabilitation is key. Although it is reasonable to briefly immobilize the injured muscle, it is important to begin gentle range of motioning exercises early. After a strain, muscles will become less flexible and weaker, so stretching and strengthening exercises are necessary. Throughout rehabilitation, all exercises should be pain-free to avoid further aggravating the injury. It is prudent to have a physical therapist guide rehabilitation and help determine when it is time to return to sports. In general, when range of motion is full and strength is near normal, it is time to start more functional exercises like light jogging and then running. Full return to sports is typically allowed after the athlete successfully performs sport-specific activities and drills without pain.
Learn more about preventing sports injuries.