Past Your Prime Podcast – Episode 16 Recap
Flexor digitorum brevis heel pain is one of the most overlooked causes of persistent heel discomfort—and it’s often misdiagnosed as plantar fasciitis. In Episode 16 of the Past Your Prime podcast, Craig Smith (physical therapist and foot specialist) and Alex Keicher (professional volleyball player) break down why your foot pain might not be what you think—and what to do if traditional plantar fasciitis treatments aren’t working.
Here’s what you’ll learn:
The Real Culprit: Flexor Digitorum Brevis Heel Pain
Most people are told their heel pain is caused by the plantar fascia. But in Craig’s clinical experience, that’s often wrong. The real issue? A muscle in the bottom of the foot called the flexor digitorum brevis.
Unlike the plantar fascia, which is a passive tissue, the FDB is active—it can cramp, fatigue, and respond to overload like any other muscle. That distinction changes everything about how to diagnose and treat heel pain.
If you are not certain if diagnosis matters, listen to Episode 3, When And Why Your Diagnosis Matter.
The 7 Signs Your Heel Pain Isn’t Plantar Fasciitis
1. Cramping in the Bottom of Your Foot
If your toes curl involuntarily or feel stuck, it’s likely a muscle problem—not fascia. The FDB is often the muscle responsible for these midfoot cramps.
2. Pain with Resisted Toe Flexion
Try curling your toes and applying resistance (or have someone gently pull against them). If that hurts or causes a cramp, it points toward FDB dysfunction.
3. Pain During Mid-Stance or Terminal Stance
Pain when your body is fully weight-bearing on one foot (mid-stance) or just before push-off (terminal stance) suggests the muscle is being overloaded. Fascia pain, on the other hand, tends to show up at toe-off.
4. Tenderness That Changes with Toe Position
If pressing the heel while your toes are pulled back hurts less than pressing it when your toes are relaxed, that implicates the FDB (not the fascia).
5. Pain After Exercise, Not During
FDB injuries often behave like tendon problems—fine during activity but painful or crampy afterward.
6. Calluses, Blisters, or Worn Insoles under Your Toes
Are there holes in the footbeds of your shoes? Calluses under your toes? These are signs you’re overusing your toe flexors for stability—classic FDB overuse behavior.
7. Abnormal Gait (Walking Pattern)
If you shorten your stride, avoid putting weight through your foot, or walk “funny” to avoid heel pain, it’s often the FDB—not the plantar fascia—that’s triggering your body to protect itself.
Misleading Symptoms That Don’t Help Diagnosis
Morning pain? Pain on the heel? Feeling better after rolling your foot? Those symptoms are common in both plantar fasciitis and flexor digitorum brevis heel pain. They don’t differentiate the two.
Why This Matters
If your heel pain has lasted longer than a few weeks, if stretching isn’t helping, or if you’re being told you need injections or orthotics—you need to consider your FDB.
Craig explains how common misdiagnoses can delay recovery or even worsen symptoms through inappropriate treatments. The good news? FDB-related heel pain responds well to the right exercises, testing, and load management strategies—many of which will be covered in the next episode.
Need Help Now?
If you suspect your heel pain is coming from your flexor digitorum brevis, don’t wait for it to get worse. Start testing for cramping, track when your pain appears, and consider finding a PT who understands muscular contributions to heel pain.
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