Swimming Tendinitis: Overuse Injuries of the Wrist, Shoulder, and Knee Tendons

Introduction

“Tendinitis” is a term familiar to many sports enthusiasts, but modern sports medicine has gradually replaced “Tendinitis” with “Tendinopathy,” because the pathological essence of chronic tendon pain is not primarily inflammatory, but rather degenerative changes in tendon tissue—disorganized collagen alignment, neovascularization, and nerve fiber proliferation. In swimming, the wrist, shoulder, and knee tendons each face their own unique patterns of mechanical stress. Once training volume exceeds the tendon’s repair rate, frustrating chronic pain gradually accumulates.

Wrist Tendinopathy

Causes

The wrist flexor tendons (especially the flexor carpi radialis) play a critical role during each stroke’s catch and pull phases. During the stroke, the wrist repeatedly transitions from extension to flexion, and combined with water resistance, this creates a continuous stretch-contraction cycle on the wrist flexor and extensor tendons. If the freestyle “early vertical forearm” technique is practiced incorrectly, the torsional stress on the wrist becomes even more pronounced.

Symptoms

• Dull pain on the dorsal or radial side of the wrist, worsening during the pulling motion
• Decreased grip strength, pain when wringing out a towel or opening a bottle cap
• Localized tenderness on palpation of the wrist

Special Note: Carpal Tunnel Syndrome

Some swimmers maintain prolonged wrist flexion, causing compression of the median nerve within the carpal tunnel, resulting in numbness in the thumb, index, and middle fingers, with symptoms more pronounced at night. If symptoms persist, medical evaluation with electrophysiological studies is needed for confirmation.

Shoulder Tendinopathy

Rotator Cuff Tendinopathy

The supraspinatus tendon is the most commonly affected tendon in swimming, with reasons detailed in the swimmer’s shoulder chapter. On ultrasound, chronic tendinopathy may show tendon thickening, structural disorganization, or calcific deposits (calcific tendinitis). The pain of calcific tendinitis is often more severe than that of general tendinopathy, and when necessary, extracorporeal shock wave therapy (ESWT) or aspiration and lavage can be performed under ultrasound guidance.

Long Head of Biceps Tendinitis

Feature	Description
Pain location	Anterior shoulder in the bicipital groove, may radiate to the anterior upper arm
Aggravating movements	Resisted elbow flexion, forearm supination, worsened during breathing/head rotation
Diagnostic tests	Speed’s Test, Yergason’s Test
Common associations	Often coexists with rotator cuff tears or subacromial impingement

Knee Tendinopathy

Patellar Tendinitis (Jumper’s Knee)

Although jumper’s knee (Patellar Tendinopathy) is more common in basketball and volleyball players, breaststroke swimmers experience instantaneous tension on the patellar tendon during the rapid whip kick that is comparable to landing from a jump. Symptoms include sharp pain at the inferior pole of the patella, which may temporarily subside a few minutes into training, but the return of pain after training is a typical characteristic.

Quadriceps Tendinitis

Less common, but can still occur during the powerful recovery phase of the breaststroke kick, presenting as pain and tenderness at the superior pole of the patella.

Scientific Management Strategies

Load Management (The Most Important First Step)

The core treatment principle for tendinopathy is “appropriate loading rather than complete rest”:

• Reduce volume, don’t stop: Completely stopping training actually leads to further tendon degeneration. It is recommended to reduce training volume to a level where pain is just controlled below 3/10.
• Avoid the reactive phase: If pain worsens within 24 hours after training beyond pre-training levels, the load is too high and needs adjustment.

Isometric Loading

Isometric contractions provide immediate analgesic effects for acute tendon pain, with the mechanism possibly related to changes in corticospinal excitability:

• Wrist flexor isometric contraction: Palm facing up, hold against fixed resistance for 45 seconds, repeat 4–5 times, 2 sets daily.
• Knee extension isometric contraction: With the knee at 60° flexion, hold against resistance for 45 seconds; the effect is most pronounced when used before training.
• Shoulder external rotation isometric contraction: With elastic band resistance, elbow fixed at the side, hold the external rotation position for 45 seconds.

Eccentric Training

Eccentric training is the most evidence-supported treatment for chronic tendinopathy, stimulating collagen reorganization through muscle contraction during the lengthening phase:

• Knee: Slow eccentric lowering on a decline squat (heel slightly elevated), 3 sets of 15 reps daily.
• Shoulder: Slow lowering phase (eccentric) of side-lying external rotation with elastic band resistance, 3 sets of 12 reps daily.
• Wrist: Slow wrist extension lowering while holding a light dumbbell (flexor eccentric), 3 sets of 15 reps daily.

Adjunctive Therapies

• Extracorporeal Shock Wave Therapy (ESWT): Effective for both calcific tendinitis and chronic tendinopathy, typically requiring 3–6 sessions.
• Platelet-Rich Plasma Injection (PRP): Has some literature support for refractory tendinopathy, but conclusions remain inconsistent.
• Taping: Kinesiology tape or rigid taping can adjust joint alignment and reduce tendon load, suitable as a training adjunct rather than a long-term solution.

Practical Recommendations

• Warm up properly before training: Perform dynamic warm-ups for each target joint with elastic bands to pre-warm the tendons under low load.
• Avoid “sudden volume increase after rest”: In the first two weeks after returning from a long break, prioritize gradually restoring training volume—this is the most common time for tendinopathy recurrence.
• Prioritize sleep and nutrition: Tendon repair primarily occurs during deep sleep, and collagen synthesis requires adequate vitamin C and protein. It is recommended to consume 1.6 g/kg of body weight in quality protein daily.
• Regular massage and fascial release: Use a foam roller to relax the muscle bellies around the tendon, helping to reduce tension at the tendon attachment site.

Conclusion

Swimming-related tendinopathy is a long-term tug-of-war between “training load vs. tissue repair rate.” Understanding the physiological characteristics of tendons and adopting scientific methods of load management and progressive strengthening addresses the root problem far more effectively than relying on anti-inflammatory drugs or passive rest. Patience and consistency are the two most important elements of tendon rehabilitation.

Related Reading

• Swimming Wrist Pain: Analysis of Wrist Joint Stress During Freestyle Catch
• Shoulder Injuries in Swimming: Causes and Prevention of Swimmer’s Shoulder
• Swimmer’s Shoulder: Identification and Causes of Rotator Cuff Syndrome
• Complete Diagnosis and Treatment Guide for Swimmer’s Shoulder