Mobility vs. Stability: Feet, Ankles, and Other Joint Chains

Feet are built to be mobile by design; they adapt their shape under load, but that means they're prone to dysfunction, such as collapsed arches, when they're asked to do too much.

Ankles are the opposite; structurally limited by design, with dorsiflexion (toes toward shins) limited more than it should be in many, meaning that when your body needs the range that dorsiflexion should provide, it will borrow it via inversion and eversion instead, aka rolling the foot inward or outward to compensate.

While this isn’t inherently wrong, it will cause problems if it becomes the default pathway, as the body will do whatever it needs to do to reach the position it needs, regardless of whether it’s the ideal way.

The practical takeaway: most people benefit from stabilizing the foot while mobilizing the ankle, particularly in dorsiflexion.

The Compensation Chain:

The general rule is that when a joint lacks mobility, the joints above or below it will sacrifice stability to make up the difference so the movement can happen; for example:

Ankle & Foot/Knee: Limited ankle dorsiflexion means the foot compensates by collapsing, and/or the knee caves inward, to reach the needed range.

Hip & Knee/Lower back: Limited hip mobility pushes the compensation down to the knee or up into the lumbar spine.

T-spine & Scapula: A stable scapula requires a mobile thoracic spine. When T-spine mobility is missing, people fake rotation by retracting one shoulder blade and rounding the other forward; it looks like rotation, but there's very little actual spinal movement happening, and your scapula goes wild.

The fix is sequential: build mobility first, then layer stability on top of it. Trying to stabilize a joint before it has the mobility it needs just teaches it to compensate.