The effect of solid ankle-foot orthoses on movement patterns used in a supine-to-stand rising task.

Background and Purpose: Within dynamical pattern theory, ankle motion can be proposed to be a control variable, and solid ankle-foot orthoses (SAFOs) can be considered a constraint to ankle movement. The purpose of this study was to examine the effect of SAFOs on movement patterns used to rise from the supine position to erect stance.
Subjects: Thirty-nine nondisabled young adults, ranging in age from 20 to 28 years (X = 22.7, SD = 1.87), participated.
Methods: Subjects were videotaped while rising from a supine position on a floor mat. Each subject performed 10 trials under each of four conditions: without SAFOs, right SAFO, left SAFO, and bilateral SAFOs. Movement patterns were described within three body components (ie, upper extremities, axial region, and lower extremities) by determining the mode and the incidence of each movement pattern under each condition. The subjects' mode movement patterns in the no SAFO condition were compared with mode movement patterns in the SAFO conditions using McNemar tests.
Results: Without SAFOs, subjects rose most commonly using a push and reach pattern of the upper extremities, a forward with rotation pattern in the trunk, and an asymmetrical squat in the lower extremities. Changes in the incidence of movement patterns occurred in all of the SAFO conditions when compared with the no SAFO condition. These changes resulted in more asymmetry when SAFOs were worn, and asymmetry was most notable in the axial region.
Conclusions and Discussion: From a dynamic pattern theory perspective, ankle motion is a control variable for the supine-to-stand rising task.