You’re probably familiar with common running injuries such as shin splints, muscle strains, and stress fractures. But if you find that your foot is swollen and painful, especially the area under your ankle, you may be suffering from a foot injury known as peroneal tendonitis.
Tendonitis—the inflammation of the tendon—occurs when a tendon is under chronic stress or it can come from another injury. The peroneal tendons are two tendons that run together on the outside of the foot and ankle. One attaches to the outside of the midfoot and the other tendon attaches to the bottom of the arch. When these tendons become inflamed, you experience peroneal tendonitis.
“The [peroneal tendons’] job is to stabilize the subtalar joint (the joint below the ankle) to keep the foot in a neutral position and to prevent inversion injuries, which happens when the ankle turns inward,” says Ashley Lee, M.D., D.P.M., a podiatrist at Sales & Deals.
What is peroneal tendonitis?
The pain usually comes on with activity (such as running) and subsides with rest. Certain activities, such as lateral motion and walking or running on uneven surfaces, can cause an increase in pain.
How does peroneal tendonitis develop in runners?
Runners typically can have issues with peroneal tendonitis when they change up their running routine. This can include trying new shoes, increasing mileage, or running on very uneven terrain. Additionally, compensating for other knee and hip issues can cause problems, says Joe Dawson, M.P.T., clinic director and senior clinician at ATI Physical Therapy.
Often, runners with supinated feet—when weight is placed on the outer edges of your feet—deal with chronic peroneal tendonitis. You can wear shoes that support this foot type, and wearing the wrong shoes causes an exaggeration in an already supinated foot. This forces the peroneal tendons to work extra hard to stabilize the foot, leading to inflammation in and around the tendon, says Lee.
“Using a stability or motion-control shoe that limits pronation in a runner with a high arched foot often places greater stress on the peroneals,” says Kent Kurfman, P.T., D.P.T., physical therapist at Furman Sportsmedicine Center. “With high arches, you see higher muscular activity in the peroneals working to anchor the first metatarsal to the ground to keep the foot stable.”
Trail runners are more likely to suffer from peroneal tendonitis due to a lack of support on uneven terrain; the peroneal tendons are constantly working to stabilize the added supination and pronation that occurs on these surfaces.
Also, peroneal tendonitis can happen from other injury—it has been associated with ankle sprains.
“The peroneal muscles are responsible for lateral foot stability, therefore inflammation or injury to these muscles will increase risk for ankle sprains as it makes the ankle less stable,” says Mirette Mikhail, P.T., D.P.T., and clinic director at ATI Physical Therapy.
How to Treat Peroneal Tendonitis
A first step to relieving your pain is to ice. “After running, use an ice cube or ice cup to slowly massage over the sore area. Do this for three to four minutes after activity as needed,” says Dawson.
Here are two exercises recommended by Kurfman:
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Loop one side of a resistance band around a table leg or other heavy anchor and the other around the outer edge of injured foot. Then, turn foot outward and bring back to midline. Perform slowly (two seconds out, hold one second, two seconds back). Repeat 3 sets of 15, once a day.
Stand with feet shoulder-width apart and arms at sides. Engage abs for stability and roll up onto the balls of your feet, lifting both heels off the floor. Then slowly lower heels back down. Do slow reps (2 second raise, hold one second, 2 seconds lower back to floor). Repeat 3 sets of 15, once a day.
Do not perform these off of the back of a step. Instead, stay on the floor. Start with double leg raises, and as pain lessens, work towards single leg raises, adding weight and decreasing reps to build strength.
You may not want to hear this, but rest is also crucial for treating peroneal tendonitis.
“In severe cases, immobilization may be necessary but not typical. A walk/run progression should not be started until pain has subsided at rest,” says Dawson. “You should be able to walk pain free for 15 minutes before starting any running progression. Perform walk/run progression every two to three days depending on symptoms.”
How to Prevent Peroneal Tendonitis
Stretching, stretching, and more stretching.
“Regular stretching of the calf and ankle is important. When doing stretching for the calf or Achilles, turn the foot inward and do the same stretch to feel a stretch along the peroneal tendons and muscle,” says Dr. Lee.
Here are two great stretches that will help strengthen your muscles and improve your balance, according to Mikhail.
Gastroc Stretch on Chair
Begin standing in behind a chair. Place both hands on the chair back and extend the left leg back and bend the right leg until you feel a stretch in the calf of the left leg and hold. Switch sides and repeat for a total of 3 times on each leg. Make sure to keep heels on the ground during the stretch.
Perform the stretch three times daily holding the stretch for at least 30 seconds and up to one minute, every day until pain subsides. After pain subsides, stretch three times daily, three days a week.
Seated Calf Stretch With Resistance
Begin sitting tall on the floor with left leg straight in front of you, holding a towel or resistance band that is looped around the bottom of the foot. Gently pull the towel toward
s your body until you feel a stretch in the back of your calf. Hold this position. Then, switch sides and repeat for a total of 3 reps on each side. Be sure to keep your leg straight and do not let your knee bend.
Perform the stretch three times daily holding stretch for at least 30 seconds and up to one minute, every day until pain subsides. After pain subsides, stretch three times daily, three days a week.
Of course, your shoe choice should also be evaluated. Your shoes should have appropriate shock absorption and arch support based on your foot structure, says Dawson. A podiatrist, physical therapist, or running shoe expert can help you find the right shoe for your needs.
“Neutral trainers should be worn by higher-arched individuals,” says Kurfman. “Complete individuals benefit from a shoe insert or custom orthotic that lifts the outer edge of the foot to lessen peroneal stress. An example of this is the DonJoy Arch Rival or the Vasyli Hoke.”
Ultimately, if you are experiencing pain that is limiting your running routine or progression, you should consult a physical therapist, podiatrist, or sports medicine doctor for further evaluation.