Why are so many of the PRI exercises isometric, rather than using the more typical type of PT exercise that uses movement against resistance?
PRI non-manual techniques are organized by muscle, position and suggested sequence of progressive application. Therefore, each technique precedes a technique that requires increased neuromotor integration, increased inhibitory activity from compensatory patterned muscle, and an increase in multilevel tri-planar positional organization. In order to carry this type of function out, the patient needs to “find” and “feel” isometrically a specific muscle in a specific position to learn a behavioral pattern or strategy with this isolated muscle engaging into an integrated “family” of muscle, without dropping off because of position or sequence of movement events. Many of the more integrated techniques do incorporate “movement against resistance” while the early techniques in each position on initiation, are isolated to inhibit undesirable compensatory activity and identified by the patient for later integration neuromuscular non-compensatory function. Without awareness of this identified and isometric trained muscle, higher levels of neuromotor demands could reduce the needed concomitant activity of this muscle.