Kirby R L, Atkinson S M, MacKay E A
Division of Physical Medicine and Rehabilitation, Dalhousie University, Halifax, Nova Scotia, Canada.
Arch Phys Med Rehabil. 1989 Sep;70(9):681-6.
With 20 able-bodied subjects, three hypotheses were tested: (1) that elevating the footrests reduces the forward stability of occupied wheelchairs, (2) that placing simulated plaster casts on the occupant's legs further reduces stability, and (3) that forward stabilizers limit the extent of dynamic forward instability. Static stability was studied on a tilting platform; dynamic stability was tested by having subjects descend a ramp. Elevating one or both footrests and adding one or two simulated casts each significantly reduced static forward stability. During dynamic testing with lowered footrests, only seven subjects tipped forward, and the extent of tip was limited by the footrests. With both footrests elevated, eight subjects tipped transiently, and 12 continued to tip until the footrests hit the floor. With the addition of simulated casts, all 20 subjects tipped fully. Elevating one footrest (with or without a cast) caused only transient tips. On a high-friction floor surface, 19 and 18 subjects (with and without casts) experienced full tips or yawing falls to the side of the elevated footrest. The addition of forward stabilizers prevented wheelchairs from full tips or falls, when the users had both legs elevated, or when one of the users' legs (p less than 0.005), was elevated while located on a high friction floor (p less than 0.005). These findings have implications for wheelchair design and prescription.
以20名身体健全的受试者为对象，对三个假设进行了测试：（1）抬高脚凳会降低乘坐轮椅的向前稳定性；（2）在乘坐者腿部放置模拟石膏模型会进一步降低稳定性；（3）前稳定器会限制动态向前不稳定的程度。在倾斜平台上研究静态稳定性；通过让受试者下斜坡来测试动态稳定性。抬高一个或两个脚凳以及分别添加一个或两个模拟石膏模型均显著降低了静态向前稳定性。在脚凳降低的动态测试过程中，只有7名受试者向前倾倒，且倾倒程度受脚凳限制。两个脚凳都抬高时，8名受试者短暂倾倒，12名受试者持续倾倒直至脚凳碰到地面。添加模拟石膏模型后，所有20名受试者均完全倾倒。抬高一个脚凳（无论有无石膏模型）只会导致短暂倾倒。在高摩擦地面上，19名和18名受试者（有和没有石膏模型）分别经历了完全倾倒或向抬高脚凳一侧的偏航摔倒。当使用者双腿都抬高，或者当一名使用者的一条腿抬高（p<0.005）且处于高摩擦地面时（p<0.005），添加前稳定器可防止轮椅完全倾倒或摔倒。这些发现对轮椅设计和处方具有启示意义。
