Abstract
We investigated the effects of seat tilting and anterior movement during forward reaching movements in the sitting position. The subjects reached for a target placed in the forward position under 2 seat conditions:a forward-tilting and back-tilting seat that could move anteriorly. Movement was measured using kinematic analysis and muscle activities. Three time phases of muscle activities were analyzed:entire reach task time, initial reach task time, later reach task time. The trunk inclination angle and the upper trunk rotation angle in the “forward-tilting seat that moved anteriorly” were less acute than that of the seat tilted back. The left external oblique muscle activities during the first phase and the left erector spinae muscle activities during the third phase in the “forward-tilting seat that moved anteriorly” were smaller than with the seat tilted back. The “forward-tilting seat that moved anteriorly” condition may have supported body movements to reduce forward trunk inclination and trunk muscles activity during forward reaching movements.
