Sitting pressure in the tilted position: manual tilt-in-space wheelchair vs. manual wheelchair with a new rear antitip device.

To test the hypothesis that, in comparison with a heavier, larger and more expensive manual tilt-in-space wheelchair, a lightweight manual wheelchair equipped with new rear antitip devices provides comparable mean sitting pressures in the tilted position, each of eight able-bodied participants sat for 8 mins in each wheelchair, upright, and tilted back (38-39 degrees). The mean (+/-SD) sitting pressures (of all active sensors in a force-sensing array) at the eighth minute in the upright and tilted positions with the new rear antitip device wheelchair were 58.6 (+/-14.0) and 45.8 (+/-9.3) mm Hg (a 20.7% reduction) (P = 0.005). For the tilt-in-space wheelchair, the mean values were 55.7 (+/-13.9) and 47.2 (+/-10.8) mm Hg (a 26.3% reduction) (P = 0.008). There were no significant differences between the wheelchairs in the upright (P = 0.843) or tilted (P = 0.624) positions. A lightweight manual wheelchair equipped with a new rear antitip device provides equivalent reductions of sitting pressures in the tilted position to a comparably tilted tilt-in-space wheelchair.