Flexor hallucis longus tendinopathy: understanding your foot pain and getting back to activity

What is flexor hallucis longus tendinopathy?

Flexor hallucis longus tendon anatomy

Flexor hallucis longus is a deep muscle in the leg whose tendon passes behind the ankle, through a narrow tunnel just behind the inner ankle bone, before reaching the big toe. It flexes the big toe and plays a key role in the push-off phase of the stride, particularly when up on the toes. This tendinopathy, sometimes called “dancer’s tendinitis”, particularly affects activities that demand being up on the toes.[1]

Why does this tendon become painful?

Pain appears when the tendon undergoes repeated friction or load in its narrow tunnel behind the ankle, particularly during repeated toe-point movements or strong push-off on the big toe.[2] Too rapid an increase in training volume or a running technique with strong forefoot push-off are common contributing factors.

Symptoms and diagnosis of flexor hallucis longus tendinopathy

Typical pain and its triggers

The pain sits behind the ankle, in the tunnel where the tendon passes, particularly when up on the toes, during strong push-off through the big toe, or on resisted flexion of the big toe. It can come with a feeling of stiffness or catching in the big toe at the end of its range.

Differential diagnosis

Several conditions located behind or around the ankle can be mistaken for this tendinopathy:

• Achilles tendinopathy, with pain more centred on the Achilles tendon rather than behind the inner ankle bone
• Posterior ankle impingement, often associated in dancers and triggered by the same toe-point movements

Causes and risk factors

This tendinopathy develops following repeated friction or overload of the tendon in its narrow tunnel behind the ankle.

Biomechanical and personal factors

• Too rapid an increase in training volume or intensity
• A running or footing technique with strong forefoot push-off
• A lack of ankle mobility that increases demand on the tendon
• A strength deficit in the big toe flexor and the foot chain

Which sports contribute to this tendinopathy?

Any sport that heavily demands being up on the toes or push-off through the big toe carries a particular risk:

• Ballet (pointe, demi-pointe)
• Running, particularly on uneven terrain
• Football and sports with fast changes of footing
• Gymnastics
• Basketball and volleyball (repeated jumping)
• Martial arts, including boxing, with forefoot weight-bearing

Treating flexor hallucis longus tendinopathy in rehab with a sports physio

The goal of treatment is to reduce friction of the tendon in its tunnel while progressively strengthening its capacity to absorb push-off load.

1. 1Reducing pain and managing load
2. 2Foot and ankle mobility
3. 3Isometric strengthening
4. 4Progressive concentric strengthening
5. 5Eccentric strengthening
6. 6Foot proprioceptive work
7. 7Correcting technique and footing
8. 8Strengthening under sport-specific load
9. 9Progressive return to running
10. 10Return to competition

“It’s not that the tendon is fragile, it’s that the load needs to be better dosed and distributed.”

Strengthening, the cornerstone of treatment

Progressive strengthening of flexor hallucis longus, combined with comprehensive foot and ankle work, restores the tendon’s capacity to withstand the push-off strain specific to your activity.

In brief

• Progressive strengthening of the big toe flexor
• Comprehensive foot chain work
• Eccentric strengthening
• Gradual return: mobility, then load, then sport

Should you rest or keep playing sport?

Total rest is generally not necessary. It’s better to temporarily adapt the toe-point movements that clearly reproduce the pain, while starting progressive strengthening of the tendon.

When should you see a specialist for this tendinopathy?

If the pain persists for more than three to four weeks, or if you feel a mechanical blocking sensation in the big toe (sometimes linked to a nodule on the tendon), a medical opinion is recommended.

Expected recovery timeline for flexor hallucis longus tendinopathy

With well-suited treatment, clear improvement is generally seen within a few weeks. As with any chronic tendinopathy, progress isn’t always linear: the tendon can stay sensitive for several weeks even as the overall pain decreases, which is why it’s worth continuing strengthening through to a full return to activity.

Preventing recurrence

Once the pain has settled, several measures can help prevent the tendinopathy from coming back:

• Keep up regular strengthening of the big toe flexor, even well after the injury
• Progress cautiously with any increase in training volume or intensity
• Maintain good ankle mobility to limit friction of the tendon in its tunnel
• Stay alert to the first signs of discomfort behind the ankle and adapt your load before it settles in

The HOPP care programmes to treat your tendinopathy and get back to sport

This tendinopathy requires progressive, well-dosed strengthening. HOPP offers you a precise exercise programme, allowing you to get back to your activities as quickly as possible.

The programme runs from 3 to 9 weeks depending on the injury and ends with a reconditioning phase allowing a return to competition in the best possible conditions. Each programme is designed by the HOPP team, made up of two sports physiotherapists who are experts in assessing and treating athletes. You’ll also find theoretical content throughout your progression, so you master every aspect of your recovery and can adjust your treatment independently. If needed, our team of physiotherapists is on hand to support you.

A programme that adapts to you every day

Every day, how you feel (RPE) is factored in to automatically adjust the rest of your programme: more load if all is well, a bit less if your foot is complaining. This daily personalisation is what makes the difference compared to a fixed, paper-based programme.

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