To understand tendinitis, you must first understand the tendon itself. A tendon is a tough, flexible, fibrous cord of tissue that connects your muscles to your bones. When a muscle contracts, it pulls on the tendon, and the tendon, in turn, pulls on the bone to create movement.

The term “tendinitis” literally means inflammation (-itis) of a tendon (tendon-). For years, it was believed that all tendon pain was caused by pure inflammation. However, modern research has shown that in most cases of chronic tendon pain, there are very few inflammatory cells present. Instead, the problem is a degenerative “wear-and-tear” condition involving disorganized and weakened tendon fibers and a failed healing response. This condition is more accurately called tendinopathy.

Although many people and doctors still use the familiar term “tendinitis,” it is helpful to think of tendon injury on a spectrum:

• A helpful analogy is to think of a healthy tendon as a brand-new, perfectly woven rope made of thousands of strong, parallel fibers.
• In acute tendinitis, it is as if this rope has been suddenly overloaded, causing some of the fibers to fray, swell, and become acutely inflamed.
• In chronic tendinopathy, it is more like the rope has been repeatedly rubbed against a rough surface for months. The fibers are not just inflamed; they are disorganized, weakened, and have tiny micro-tears. The body’s repair crew keeps trying to patch it up, but they cannot keep up with the constant strain, leading to a chronically painful and dysfunctional rope.

For the purposes of this article, we will use the common term “tendinitis” to refer to this spectrum of tendon overuse injuries.

In my experience, patients often describe tendinitis as a sharp pain that starts small but worsens with repetitive activity, especially in commonly used joints like the shoulder or elbow.

The fundamental cause of tendinitis is repetitive mechanical overload. Tendons are remarkably strong and are designed to handle significant force, but they can be injured when they are subjected to too much stress without enough time to rest and repair. This overload can happen in two main ways:

1. Repetitive Micro-trauma: This is the most common cause. It occurs from performing the same motion over and over again. The constant, repetitive pulling on the tendon leads to the accumulation of tiny tears in the tendon fibers faster than the body can heal them. This leads to degeneration and pain.
2. Sudden, Acute Injury: A less common cause is a sudden, forceful strain on the tendon, such as from lifting a very heavy object, which can cause acute inflammation.

The inflammation and degeneration seen in tendinitis are the body’s response to this mechanical stress and the subsequent micro-trauma to the tendon fibers.

I’ve often seen tendinitis result from repetitive strain, especially in patients who suddenly increase physical activity or take on new work routines without proper conditioning.

A person develops tendinitis when the load they place on a specific tendon exceeds that tendon’s capacity to handle the load. This is influenced by many internal and external risk factors.

The most common risk factors and activities that lead to tendinitis include:

• Occupation: Many jobs require repetitive motions that put specific tendons at risk. This includes carpentry, painting, plumbing, dentistry, assembly-line work, and even extensive computer use with poor ergonomics.
• Sports and Recreation: Many common forms of tendinitis are nicknamed after the sports that frequently cause them.
  • Tennis Elbow (Lateral Epicondylitis): Pain outside the elbow.
  • Golfer’s Elbow (Medial Epicondylitis): Pain inside the elbow.
  • Jumper’s Knee (Patellar Tendinitis): Pain just below the kneecap.
  • Swimmer’s Shoulder or Pitcher’s Shoulder: Pain related to the rotator cuff tendons.
  • Achilles Tendinitis: Pain in the large tendon at the back of the ankle.
• Age: As we age, our tendons naturally lose some of their elasticity and become less able to tolerate stress, making them more susceptible to injury. This is a major factor for people over 40.
• Improper Technique or Equipment: Using poor form during a sport or at work, or using improperly sized or fitted equipment (like a tennis racket with the wrong grip size), can place abnormal stress on tendons.
• Sudden Increase in Activity: A “weekend warrior” who is mostly sedentary during the week and then plays several hours of an intense sport on the weekend is at high risk for an overuse injury.

Clinically, many people don’t realize that something as simple as poor posture or repetitive typing can gradually lead to tendinitis, especially in the wrist or shoulder.

The symptoms of tendinitis are typically localized to the area of the affected tendon and the joint that it moves.

The most common signs and symptoms include the following:

• Pain: This is the hallmark symptom. It is often described as a dull, aching pain that is concentrated around the affected area. The pain is typically worse during and after activity and may be stiff and sore in the morning.
• Tenderness: The specific tendon is often very tender to direct pressure or touch.
• Mild Swelling: There may be some localized swelling, warmth, or redness over the tendon.
• Stiffness: The affected joint may feel stiff, especially upon waking.
• A Grating Sensation (Crepitus): Some people may feel or hear a grating or crackling sound when they move the tendon.

Patients often tell me the pain starts as a dull ache but quickly turns sharp with movement especially in joints like the elbow, heel, or shoulder.

Diagnosis of tendinitis is almost always clinically. This means a doctor can confidently diagnose the condition based on a detailed medical history and a thorough physical examination.

• Medical History: Your doctor will ask about the nature of your pain, what activities make it worse, your occupation, and your recreational habits.
• Physical Examination: This is the key to diagnosis. The doctor will:
  • Palpate the area to pinpoint the exact location of the tenderness along the tendon.
  • Assess the joint’s range of motion.
  • Perform specific provocative maneuvers. This involves having you move your joint against resistance to stress the specific tendon in question. If this maneuver reproduces your exact pain, it strongly suggests a diagnosis of tendinitis.

When is Imaging Needed?

For a straightforward case of tendinitis, imaging tests are often not necessary. They are typically ordered if the diagnosis is unclear, if the symptoms are not improving with initial treatment, or to rule out other problems like a fracture or severe arthritis.

• X-ray: An X-ray does not show soft tissues like tendons, but it can be used to rule out bone problems or to look for calcium deposits within a tendon (calcific tendinitis).
• Ultrasound: A musculoskeletal ultrasound is an excellent, non-invasive tool that can create real-time images of the tendon. It can show tendon thickening, inflammation, or tears.
• Magnetic Resonance Imaging (MRI): An MRI provides the most detailed images of the tendon and all the surrounding soft tissues and can be used to assess the severity of tendon degeneration or to identify a tear.

Clinically, I usually rely on a focused physical exam and history to diagnose tendinitis. Imaging like ultrasound or MRI is only necessary when symptoms are severe or unresponsive.

The treatment for tendinitis is focused on relieving pain and reducing inflammation in the short term, and then addressing the underlying cause of the strain to allow the tendon to heal and to prevent the problem from recurring. The approach is almost always stepwise.

Phase 1: Initial Self-Care and Pain Control

The first and most important step for any acute tendon injury is the RICE protocol:

• Rest: You must stop or significantly modify the activity that is causing the pain. This is the most crucial step. Pushing through the pain will only make the condition worse and lead to a chronic problem.
• Ice: Applying an ice pack to the affected area for 15-20 minutes several times a day can reduce pain and inflammation.
• Compression: Using an elastic bandage to wrap the area can help reduce swelling.
• Elevation: Keeping the injured area elevated above the heart level can also help with swelling.
• Over-the-Counter (OTC) Medications: Short-term use of nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen or naproxen, can be effective at reducing both pain and inflammation.

Phase 2: Physical Therapy and Rehabilitation

Once the initial, acute pain has subsided, rehabilitation with a physical therapist is the cornerstone of long-term recovery and prevention. A physical therapist will:

• Identify the Underlying Cause: They will analyze your posture, biomechanics, and movement patterns to identify any issues with technique or muscle imbalances that are putting excess stress on the tendon.
• Develop a Stretching and Strengthening Program: The key to treating chronic tendinopathy is a specific type of exercise called eccentric exercise. These are exercises that focus on strengthening the muscle while it is lengthening. Eccentric exercises have been shown to stimulate collagen production and help remodel and heal the damaged tendon.
• Provide Other Therapies: A therapist may also use techniques like deep tissue massage, ultrasound therapy, or athletic taping to aid in recovery.

Phase 3: Medical Interventions

If conservative care does not provide relief, your doctor may suggest other treatments.

• Corticosteroid Injections: A powerful anti-inflammatory steroid can be injected around the tendon. While this can provide very effective short-term pain relief, it is used with caution.
• Platelet-Rich Plasma (PRP) Injections: This newer therapy involves drawing your own blood, concentrating the platelets (which are rich in growth factors), and then injecting them into the damaged tendon to stimulate a healing response. Its effectiveness is still being studied.
• Dry Needling: This involves repeatedly puncturing the tendon with a small needle to stimulate blood flow and a healing response.

Phase 4: Surgery

Surgery is a last resort, reserved only for severe, chronic tendinitis that has failed to respond to many months of conservative treatment, or for a full tendon rupture. The surgeon will remove the damaged, degenerative tendon tissue or surgically repair the tear.

Patients often feel surprised that rest, ice, and structured physical therapy are more effective long-term than painkillers alone, it’s consistency that makes the difference in recovery.

Tendinitis is an extremely common overuse injury that serves as a direct signal from your body that a tendon is being stressed beyond its limit. The nagging pain and tenderness can significantly limit your ability to work, play, and enjoy your daily activities. While the initial response should always be rest and pain control, the key to true, lasting recovery lies in addressing the root cause of the problem. A dedicated program of physical therapy, particularly with a focus on specific strengthening exercises, is essential for healing the damaged tendon and correcting the underlying mechanical issues. By listening to your body, seeking a proper diagnosis, and committing to a rehabilitation plan, you can effectively treat the pain, build more resilient tendons, and prevent frustrating injuries from recurring in the future.

American Academy of Orthopaedic Surgeons (AAOS). (n.d.). Tendinitis. Retrieved from https://orthoinfo.aaos.org/en/diseases–conditions/tendinitis/

Mayo Clinic. (2024). Tendinitis. Retrieved from https://www.mayoclinic.org/diseases-conditions/tendinitis/symptoms-causes/syc-20378243

Cleveland Clinic. (2023). Tendinitis. Retrieved from https://my.clevelandclinic.org/health/diseases/10939-tendinitis