Tibialis Posterior: The Quiet Muscle That Holds the Arch — and the Chain Above It

Paulius Jurasius
1 hour ago
2 min read

My Dear Reader,

Some muscles announce themselves loudly when they fail.Others disappear quietly — and let the damage travel upward.

The tibialis posterior belongs firmly to the second group.

At JANMI Postural Pain Clinic in Marylebone, this muscle has become one of our most researched and consistently underperforming sleepers in modern bodies. Not because it is weak by design — but because modern movement rarely asks it to do its real job.

What and where is tibialis posterior?

Anatomically, tibialis posterior is a deep muscle of the lower leg.It originates on the posterior tibia and fibula and travels behind the medial malleolus (inside ankle bone), inserting into multiple bones of the midfoot, including the navicular.

Its function is complex and often misunderstood. Tibialis posterior:

supports and dynamically controls the medial longitudinal arch
decelerates foot pronation during gait
coordinates foot stiffness during push-off
links foot mechanics to knee, hip, and pelvic control

It is not a “foot muscle” in isolation.It is a load-translator between ground and body.

Why I call it a sleeper

In healthy movement, tibialis posterior works continuously and quietly, especially during walking, hiking, uneven terrain, and load carriage.

Modern life removes most of these demands.

Shoes stabilise the arch externally.Floors are flat and predictable.Walking volume is low and rushed.Movement variability is minimal.

The result is subtle but profound:

tibialis posterior loses timing, not necessarily strength
pronation becomes uncontrolled rather than adaptive
the arch collapses passively instead of responding dynamically

This is a classic JANMI pattern:a stabiliser that should work all day is asked to wake up only during exercises — and eventually stops responding.

Where this shows up clinically

In practice, inhibited tibialis posterior often sits behind:

foot fatigue and collapsing arches
plantar fascia irritation
Achilles and calf over-activity
inward knee drift (dynamic valgus)
hip overuse and pelvic asymmetry

The knee or hip often becomes the complaint.The foot is rarely blamed — but frequently responsible.

Evolutionary perspective

Our ancestors walked barefoot or minimally shod over uneven terrain, carrying loads, changing direction, and adjusting foot stiffness constantly.

Tibialis posterior was trained reflexively, not deliberately.

Modern humans:

outsource arch control to footwear
remove sensory input from the sole
reduce walking variability

The muscle does not fail structurally.It fails neurologically and coordinatively.

The JANMI focus

At JANMI, we do not “strengthen the arch” in isolation.

Our current research and clinical implementation focuses on:

restoring timing and eccentric control, not maximal force
integrating tibialis posterior with hip and pelvic stabilisers
using short, low-load, high-quality drills that mimic walking demands
avoiding over-cueing, gripping, or rigid foot postures

The goal is not to hold the arch up.The goal is to let the foot respond intelligently to load.

A note on exercises

Yes, there are effective activation strategies for tibialis posterior — but many popular drills over-recruit superficial muscles or reinforce stiffness.

At JANMI, we prioritise: