The effect of restricting arm swing during normal locomotion.

This work examined possible perturbations in contra-lateral upper and lower limb motion, movement variability, and thoracic rotation, when a healthy mature adult walked a distance of 12 m at self-paced speed with and without unilateral passive arm restraint. The 2-dimensional walking data captured from 11 reflective markers placed on the subject's right side were recorded sagitally along the plane of progression using an electronic camera and Peak-5 Performance Video-system. The positional data were calculated off-line and differentiated with respect to one representative stride using Lab View software. Data were analyzed for 5 successive trials of normal walking; 5 successive walking trials with unilateral passive restraint; and a further 4 without restraint. Under the restrained condition the results showed: a) A significant decline in horizontal displacement of the limbs; b) higher variability of the trajectories generated, particularly at the ankle; c) a trend towards greater thoracic rotation on the unrestrained side; and d) altered angular velocity profiles for all upper and lower limb joints and trunk, which did not always return to baseline values after restraint removal. Since motivation level, environment, and methodology was consistent across trials, the findings suggest relatively stereotyped locomotor patterns in mature humans can be readily modulated in response to task constraints.