Dedicated runners know tendonitis all too well—a recurrent issue that can derail your training routine. Tendonitis from running is not just painful; it can also linger for a long time and hurt performance. What exactly is tendonitis, how does it present, and can you keep running with it? Here is what you need to know about this injury and how to prevent it.
The six types of runner's tendonitis at a glance
Pinpoint the location of your pain to identify the most likely issue. This table is not a substitute for a medical diagnosis: only a healthcare professional can confirm the source of tendon pain.
| Type | Pain location | Trigger conditions |
|---|---|---|
| Patellar | Base of the knee, below the kneecap | Long distances, uphills and downhills |
| Achilles tendon | Back of the heel | Long runs, downhill terrain, unsuitable footwear |
| Posterior tibial | Inside of the ankle and arch of the foot | Uneven ground, elevation gain/loss, trail running |
| Iliotibial band | Outer knee | Long distances, repetitive movement |
| Gluteus medius | Outer hip | Muscle imbalances, running form |
| High hamstring | Back of the thigh, ischium | Often mistaken for sciatica |
What is tendonitis in runners?
Tendonitis refers to an injury or irritation of tendons—the fibrous connective tissues that attach muscles to bones. When running, tendons are under constant strain from each stride and sudden changes in direction, leaving them vulnerable. Tendons face repetitive microtrauma caused by impacts, friction, and sustained effort.
An important distinction: the term tendonitis suggests inflammation, which is how these conditions were described for years. Sports medicine has since updated this view. Most long-standing tendon issues stem from progressive tendon degeneration rather than inflammation—a condition known as tendinopathy. This nuance matters: it changes the treatment approach, particularly regarding complete rest and anti-inflammatories, making a proper diagnosis even more essential than self-treatment.
Tendonitis typically occurs after overuse, excessive intensity, or wearing unsuitable shoes. It can also stem from poor running form or excessively harsh terrain.
What causes tendonitis?
Tendons endure constant stress during physical activity, particularly in running. When the load persistently exceeds the tendon's capacity to recover, its fibres break down faster than they can repair. Here are the primary risk factors for developing tendonitis:
- Overuse: excessive training without adequate recovery. This is by far the most common cause.
- Microtrauma: repetitive motions that do not allow sufficient recovery time between sessions.
- Poor shoe choice: improper footwear alters load distribution. In particular, the heel-to-toe drop directly affects tension on the Achilles tendon.
- Demanding terrain: running on hard or uneven surfaces places extra stress on tendons.
The same overload mechanism can cause other injuries, such as stress fractures. Our advice on preventing injuries and reducing mechanical stress applies to all these conditions.
What types of tendonitis affect runners?
1. Patellar tendonitis
This tendonitis affects the patellar tendon that connects the kneecap to the shinbone. It is common among long-distance runners and typically presents as pain at the base of the knee, aggravated when running uphill or downhill. If you mainly experience discomfort while hiking, check out our guide on knee pain when hiking.
2. Achilles tendonitis
Achilles tendonitis is one of the most common running injuries. It affects the Achilles tendon located at the back of the heel. Pain is felt especially after long runs or downhill routes. Wearing inappropriate footwear can also aggravate the condition.
3. Posterior tibial tendonitis
Trail runners are especially prone to this condition. The tibialis posterior muscle sits deep in the lower leg, but its tendon runs behind the medial malleolus—the bony bump on the inside of the ankle—before attaching to the arch of the foot. This is where the pain develops, on the inside of the ankle and under the foot, rather than in the calf. It often strikes when running on uneven terrain or steep gradients. Not to be confused with other types of calf pain in running, which have various causes.
4. Iliotibial band tendonitis
Commonly known as IT band friction syndrome or runner's knee, this condition affects the outside of the knee and typically stems from repetitive motion over long distances. It is particularly prevalent among long-distance runners.
5. Gluteus medius tendonitis
It causes pain on the outside of the hip and is more common in women. It can result from muscle imbalances or inefficient running form.
6. High hamstring tendinopathy
Affecting the ischial tuberosity, this type of tendonitis causes pain high up at the back of the thigh, where the hamstrings attach to the pelvis. It is frequently mistaken for sciatica, but requires a completely different treatment approach.
What are the symptoms of tendonitis?
Symptoms vary depending on severity and location, but common signs include:
- Localised pain: felt directly on the tendon during physical effort.
- Swelling: inflammation and puffiness can appear around the affected tendon.
- Stiffness: the affected area loses flexibility, restricting movement—especially first thing in the morning.
- Tenderness to touch: the affected tendon is generally sensitive to pressure and can feel warm.
- Sharp pain during activity: it increases while running and can persist afterwards.
Can you keep running with tendonitis?
The answer depends on severity. In the early stages, running may still be manageable but must be approached cautiously. If pain is mild, reducing your volume and adjusting intensity may be enough. In cases of acute or persistent pain, it is strongly advised to consult a healthcare professional rather than pushing through.
- Reduce training load: cut back on sessions that stress the tendon without necessarily stopping all activity.
- Apply ice after running if the area is hot and swollen.
- Stretch gently: avoid sudden jerks and painful overstretching.
- Get professional advice: an accurate diagnosis prevents you from treating the wrong issue for months.
How do you prevent tendonitis when running?
- Build up gradually: never increase your weekly volume by more than 10% from one week to the next. It is the single most effective—and most overlooked—rule.
- Mix up your terrain: alternate between flat surfaces, soft ground, and hard pavement to avoid overloading the exact same tendon.
- Choose footwear tailored to your feet and your running style, and replace your shoes before they wear out.
- Warm up properly before your session and give your body enough recovery time between workouts.
Frequently asked questions
How long does runner's tendonitis last?
It varies greatly depending on how long the condition has been present. Early management, with load reduction from the very first symptoms, often takes just a few weeks. A chronic issue present for months requires a longer rehabilitation process—which is why seeking medical advice early is key.
Should you apply heat or ice to tendonitis?
Ice is generally used after training when the area feels warm and swollen to help relieve pain. Heat is best suited for morning stiffness before heading out. Neither cures the underlying problem: adjusting your training load is what truly matters.
Can you run with Achilles tendonitis?
For mild discomfort that fades during warm-up, light running is often still feasible. However, as soon as the pain increases while running, persists afterwards, or alters your gait, you must stop and seek advice. Pushing through worsening pain will significantly prolong your recovery.
When should you see a specialist?
Seek medical advice if the pain persists for more than ten to fifteen days despite reducing your training load, if it occurs at rest or at night, if the area is swollen or very tender, or if it forces you to alter your running gait.
Tendonitis is not an inevitable part of running. It can be prevented by listening to your body, progressing gradually, and using the right gear. Pay attention to your running technique and do not hesitate to dial back your training load at the first warning signs.
This article is for informational purposes only and does not replace medical advice from a doctor, sports physician, or physiotherapist.
