Physical Therapy for Swimmer’s Knee

Swimmer’s knee is caused by repetitive strain on the knee ligaments, particularly the MCL, when performing the breaststroke. Pain in the MCL develops due to the repetitive flexion-extension, adduction, and external rotation of the knee against the water when completing the breaststroke. When doing the breaststroke, 70% of the propulsion of the stroke comes from the legs and knees, placing significant stress on the knees. Physical therapy can alleviate swimmer’s knee pain and restore movement and function in the knee safely through a targeted therapeutic exercise and manual therapy rehabilitation program.

What is Swimmer’s Knee?

Swimmer’s knee is one of the most common swimming injuries, caused by repetitive strain on the knee ligaments, particularly the MCL, when doing the breaststroke. The MCL, or medial collateral ligament, is a thick inner knee ligament that helps stabilize the inner part of the knee. Pain in the MCL develops due to the repetitive flexion-extension, adduction, and external rotation of the knee against the water when completing the breaststroke.

When doing the breaststroke, a great deal of strain is placed on the legs and knees. In fact, 70% of the propulsion of the stroke comes from the legs and knees while the rest of the power comes from the arm pull of the breaststroke. Breaststroke requires a whip kick motion technique, involving bending the legs toward the thighs and the thighs toward the hips at an angle of 120 degrees. Considerable torque and lateral stress are placed on the knee joint during the whip kick motion as the knee moves rapidly from flexion into extension with external rotation of the lower leg. Then, the feet sweep outward to get into position to push against the water, pushing with the inside of the feet, performing an energetic out and in whipping motion. The feet then come together and relax as the swimmer enters the glide phase of the stroke while sweeping the arms front and then outwards to move forward.

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There are a number of factors that can contribute to the development of swimmer’s knee:

• Lack of stability in the kneecap can cause swimmer’s knee as the force generated by the breaststroke kick can create an unnatural lateral flexion of the knee, placing stress on ligaments. Lack of knee stability can also lead to misalignment of the knee joint which can further damage the meniscus and ligaments.

• Limited mobility in the hip joint can lead to medial knee pain, such as decreased internal hip rotation and limited hip extension. Lack of flexibility in the quadriceps and hamstring muscles can place additional stress on the knee and MCL during the breaststroke kick. Strong and flexible quadriceps and hamstrings can reduce the amount of stress on the knee joint by bearing some of the stress of the lateral movement of the breaststroke kick.

Symptoms of swimmer’s knee can include:

• deep pain in the knee that begins gradually and worsens in severity over time due to repetitive stress on the knee

• swelling at the injury site

• limited knee range of motion

• bruising and tenderness at the knee

• tingling or numbness in the thigh muscles

• muscle spasms in the leg and knee

• reduced upper leg strength

• pain when directly using the quadriceps and knee when swimming

Various studies have found that breaststrokers are more likely to experience knee pain than those swimmers who specialize in different swim strokes. Of 26 breaststroke specialists, 86% report having experienced knee pain, 47% of whom had knee pain at least once a week. Researchers found that breaststrokers that experienced pain more often had less internal rotation in their hips, had increased training volume of the breaststroke, and had not done a sufficient warm-up prior to training.

Physical Therapy for Swimmer’s Knee

Physical therapy can alleviate swimmer’s knee pain and restore movement and function in the knee safely through a targeted therapeutic exercise and manual therapy rehabilitation program. The therapist first performs a physical examination of the swimmer to assess the injury and design a treatment program tailored to the swimmer’s specific needs. The physical exam can include palpation of the knee joint; ligament stress tests to assess pain tolerance and/or laxity of the MCL; strength and flexibility tests of the knee joint; range of motion assessment of the knee; and strength tests of the quadriceps, hamstrings, and adductor muscles.

Physical therapy treatment for swimmer’s knee can include:

• Pain management using ice and electrotherapy

• Manual therapy soft tissue and joint mobilizations to relieve pain and gently improve range of motion

• Dry needling of taut muscle bands that are limiting mobility in the leg

• Targeted strengthening exercises of the hip muscles, quadriceps, hamstrings, gluteal muscles, and core for improved stability and strength to tolerate the stresses of the breaststroke

• Swim stroke technique correction to minimize stress on knee as much as possible

• A graded exposure to load program for the knee ligaments to rebuild tolerance to force and load

To prevent the development of swimmer’s knee:

• Always warm up properly with dynamic stretching and a slow easy swim to increase muscle temperature and increase heart rate.

• Stretch after a workout which helps muscles heal more quickly after strenuous use by gently lengthening them.

• Strength train on dry land, targeting your knee, hip, quadriceps, and hamstring muscles.

• Engage in mobility training of the knees, hips, groin, and piriformis.

• Rotate strokes and workout activities, particularly if you begin to experience knee pain. Refrain from aggravating activity to allow the muscles of the knee to heal.