Releaser (Flatfoot) vs Bracer (Cavus Foot)
Because muscles act in chains, and not individually, the shape of the foot's inner longitudinal arch indicates global tonicity patterns. A flatfoot (releaser) suggests the posterior chain is hypotonic. A high arch foot (cavus) suggests the posterior chain is hypertonic.
Proprioceptive Insoles change tonicity patterns, documented by the Cuernavaca Study