Changes in spinal posture, muscle activation, center of pressure and discomfort while standing with different footrest heights during a standardized computer task

Abstract

Standing aids are recommended for individuals who are expected to stand for prolonged periods of time in the workplace to reduce the risk of developing low back pain (LBP). The purpose of this study was to examine how footrest usage, and footrests of differing heights, affect measures of posture, muscle activation, weight distribution, centre of pressure, and discomfort while working at a standing workstation. Four standing positions were compared: flat ground stance, and standing with a low (10 cm), medium (20 cm) and tall footrest (30 cm). Using a footrest significantly altered lumbo-sacral angle, lumbar-to-thigh angles, gluteus medius and lumbar erector spinae muscle activity, and COPrange in the elevated limb. Discomfort increased over the 15 minute trial regardless of condition. The medium (20cm) footrest provided unique advantages over the other footrest heights and should therefore be recommended in situations where an absolute footrest height is preferred.