Foot pain for this Royal Marine

When someone arrives with pain at the back of the heel or lower calf, it’s almost a reflex for the term “Achilles” to come up early in the conversation — usually accompanied by a familiar story: pain that’s been there a while, previous attempts at rehab, and a growing frustration that things aren’t improving. That was exactly the case recently when I saw a Royal Marine who had been battling symptoms for over 18 months, with what he and several others had assumed was an ongoing Achilles problem. In this case, the correct plantaris foot pain diagnosis changed everything.

For someone in the forces, this kind of issue doesn’t just mean missing a few runs — it impacts everything. Load-bearing, high-intensity movement, even the ability to pass certain physical assessments. So, understandably, he was highly motivated to get back to full function, and equally frustrated that nothing had worked so far. Despite various things being tried — from rest and recovery, soft tissue work with a Sports Therapist to progressive loading — he was still in pain.

Foot pain assessment

From our first session, I had a hunch we might not be dealing with a textbook case of mid-portion or insertional Achilles tendinopathy. His pain location wasn’t entirely typical, and certain clinical markers didn’t quite add up. His strength under load was good, but provocative movements didn’t consistently correlate with tendon-based symptoms. It was enough of a mismatch that I decided to refer him for a diagnostic ultrasound — something I often do when I want a clear look at what’s actually going on under the surface.  

Plantaris Diagnosis

Sure enough, the scan revealed that the Achilles itself was structurally sound. No signs of degeneration or reactive thickening. But what did stand out was inflammation and irritation of the plantaris muscle — a smaller, thinner structure that runs close to the Achilles and can mimic its symptoms almost perfectly.

In some individuals, the plantaris even wraps around or embeds into the Achilles tendon, making it incredibly difficult to distinguish without imaging.

This was a classic case of plantaris foot pain, misattributed to the Achilles. A proper diagnosis of plantaris involvement was key.

Once we had a proper diagnosis, we could start treating the right problem. That clarity changed everything.

Treatment of Plantaris

Shockwave therapy was central to the turnaround. By targeting the irritated plantaris region specifically — rather than the Achilles area — we were able to stimulate healing, improve tissue quality and reduce pain almost immediately. There’s a growing body of evidence supporting the role of radial shockwave wave therapy in managing soft tissue pain syndromes, and in this case, it was genuinely transformative. No injections, no surgery, just a biological stimulus to encourage the body to reset and repair.

However, passive treatment alone wasn’t enough — especially not for someone in such a high-performance role. So, we tweaked his tailored, progressive loading and retraining programme to be more specific and structured – all while respecting tissue healing times and symptom response.

Within a few weeks, he was reporting significant improvements. Movements that used to bring on pain were now pain-free. His confidence in that limb returned. And importantly, he was able to re-engage with his physical training regime without needing to mask symptoms or back off at the first sign of discomfort.