01/07/2026
Woody Click and Brian Klatt. Look at this explanation.
Why a “self-adjusting palmar angle” (banana) shoe always rotates cranially, explained by PoB
A banana shoe (or so-called self-adjusting palmar angle shoe) works in a very consistent way.
When the belly of the shoe is placed under the coffin joint centre of rotation (CoR), the foot will rotate cranially and the palmar angle will rise. An “air wedge” is formed.
That outcome isn’t accidental, and it isn’t because the shoe is “forcing” the foot to move. The shoe is passive. What it does is remove geometric resistance and allow the limb to respond to its own internal mechanics.
This is where the Point of Balance (PoB) explains what’s actually happening.
PoB describes the moment-equilibrium requirement of the digit at midstance, the point at which internal flexor moments and the opposing ground reaction force are balanced about CoR.
When the belly of a banana shoe sits under CoR, the limb is intentionally placed in a non equilibrium state relative to PoB. The internal moment environment cannot balance there.
As a result, the system does what physics demands, it rotates cranially to shorten the effective lever arm and reduce joint torque. Forward rotation continues until the moment conditions are satisfied. In other words, until the PoB condition or concept is reached. At that point, rotation stops and equilibrium is restored.
This is why banana shoes are so consistent in their effect. They don’t “set” a palmar angle. They allow the limb to find equilibrium for itself.
Importantly, this also shows something fundamental.
Balance around CoR is not, by itself, an equilibrium state. CoR is the correct anatomical reference, but equilibrium depends on how forces are resolved AROUND it. The PoB concept defines that requirement.
What’s clever about the banana shoe is that it deliberately uses this non-equilibrium state to therapeutic advantage. By placing the shoe belly under CoR, we allow the limb to self-adjust until internal and external moments are balanced. The shoe doesn’t create motion, it permits the motion required to satisfy equilibrium.
If the belly of the shoe were placed at PoB, rotation would not occur. The system would already be balanced. That’s why the behaviour of the banana shoe is such a clean, real-world example of PoB in action. It clearly shows that PoB is “the point of balance”.
So PoB isn’t a new point to chase or a rule to apply blindly. It’s a framework that explains
• why banana shoes work,
• why they always rotate cranially,
• and how we can intentionally manipulate moment balance around CoR to manage hoof orientation.
It’s not new magic, it’s physics made visible.