The Effect of Modified Sitting Postures on Postural Sway and Reach Distance in Sitting

Purpose: Sitting is a common and familiar position used daily as a platform for many motor activities. The goal of the study was to investigate how difference in the chair design and selected sitting manipulations contribute to reach distance in sitting. Method: Ten healthy subjects were required to perform reaching forward while sitting in an adjustable chair with 0, 10 forward or 10 backward inclination of the seat, with and without footrest and leg support and when holding the edge of the seat with the contralateral arm and legs crossed. Results: In comparison to sitting with feet on the footrest, the reaching distance decreased significantly when sitting on either forward or backward inclined seat (p<0.05) and it increased when the subjects held the edge of the seat while seated with footrest and the posterior leg support (p<0.05). There was no major effect of crossing the legs or the use of anterior leg support on the maximal reach distance. Conclusions: Modification of the chair design could increase or decrease reaching distance in sitting. The outcome of the study provides a background for future investigations of the effect of sitting positions on reaching distance in individuals with impairments who spend most of their time in sitting.