The flexor hallucis longus (FHL) tendon is a long tendon that originates deep underneath your calf muscles and reaches all the way to the base of your big toe. The synovium, the outer layer of the tendon, can become inflamed due to repetitive stresses like excessive sports training. This results in FHL tenosynovitis; here are three things athletes need to know about this painful sports injury.

What are the signs of FHL tenosynovitis?

The main symptoms of FHL tenosynovitis are pain and swelling on the back of the ankle and on the sole of the foot. The pain tends to be worse with activity, especially activities like jumping or walking on the balls of your feet.

How do sports cause it?

Sports that regularly put your FHL tendon under excessive strain can lead to this injury. It tends to affect ballet dancers who dance en pointe. Dancing on the tips of the toes puts your ankles in a very unnatural position, and over time, it irritates the FHL tendon.

Ballet dancers aren't the only athletes that can develop this injury. Sports that involve a lot of running and jumping can also irritate the tendon over time. This irritation comes from forcefully pushing yourself forward with your forefoot. Athletes such as runners, track-and-field athletes, gymnasts, and others can injure themselves in this way.

How is it treated?

Treatment for FHL tenosynovitis is similar to the treatment for other athletic injuries and involves stopping sports and following the R.I.C.E. guidelines. You'll be directed to rest, hold ice or cold compresses against the sore areas, compress the area with athletic tape, and keep your injured ankle elevated.

In severe cases, athletic tape won't be enough, and you may need to wear a cast or a boot. This keeps your tendon immobilized while it heals. Your podiatrist may recommend getting crutches to make it easier for you to get around.

Steroid injections can also help reduce your pain and discomfort. Your podiatrist will inject the steroids directly into the outer layer of your tendon; ultrasound imaging will be used to make sure the medication is injected into the right spot.

It's important to wait until you're cleared for athletic activity to start training again. Training when you're not completely healed can make your injury worse and keep it from healing properly, which can have devastating consequences for your athletic career.

If your ankle or foot hurts during training, you may have FHL tenosynovitis and should see a podiatrist right away.