Effect of Seat Belts and Shoulder Harnesses on Functional Arm Reach

Abstract

A laboratory study was conducted to evaluate the effects of three different types of harnesses (lap belt, lap belt with crossed shoulder harness, and lap belt with parallel shoulder harness) on functional arm reach. Six male college students grasped a rotatable cylindrical handle as far away from the seat reference vertical line as was comfortably possible. Three different vertical heights and eight different azimuth angles were used. Contour curves for the reach envelopes are presented. The type of harness and height level had a significant effect on arm reach. Reach envelopes for the crossed and parallel harnesses were, on the average, 15 and 24% lower than the reach envelope for the lap belt. Of the three reach heights compared, the 110.5-cm reach envelope provided the greatest functional arm reach.