Majaess G G, Kirby R L, Ackroyd-Stolarz S A, Charlebois P B
Department of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada.
Arch Phys Med Rehabil. 1993 Sep;74(9):977-82.
We tested the hypothesis that moving the seat of an occupied wheelchair forward would decrease the wheelchair's forward and increase its rear static and dynamic rotational stability, and that moving the seat backward would have the opposite effect. We studied 21 able-bodied subjects in a lightweight, manually propelled wheelchair with the occupied seat in the normal position, 5cm forward, and 5cm backward. Regression analysis revealed that, within the range studied, the relationship between seat position (chi, in cm) and the forward and rear static stability (SSf and SSr, in degrees) could be expressed by the linear equations SSf = 15.52 (0.06)-0.70 (0.01) chi (r2 = 0.98) and SSr = 24.55 (0.07) + 1.11 (0.02) chi (r2 = 0.99). These findings were consistent with the results of a computer model that we used to predict the nature and extent of the effect on static stability, except that the model showed that the relationship becomes nonlinear with seat-position changes greater than those we studied. The relationship between seat position and dynamic forward and rear stability (DSf and DSr, the threshold speed [in m/s] required to induce a transient tip) could be expressed by the equations DSf = 0.74 (0.01)-0.041 (0.002) chi (r2 = 0.91) and DSr = 0.63 (0.01) + 0.030 (0.002) chi (r2 = 0.91). The results support our hypothesis and indicate that seat position is a very significant determinant of wheelchair stability.
将有人乘坐的轮椅座位向前移动会降低轮椅向前的速度，并增加其后部的静态和动态旋转稳定性；而将座位向后移动则会产生相反的效果。我们对21名身体健全的受试者进行了研究，他们乘坐的是一辆轻型手动轮椅，座位处于正常位置、向前5厘米和向后5厘米的状态。回归分析表明，在所研究的范围内，座位位置（以厘米为单位的χ）与前后静态稳定性（分别为SSf和SSr，以度为单位）之间的关系可以用线性方程SSf = 15.52 (0.06) - 0.70 (0.01)χ（r2 = 0.98）和SSr = 24.55 (0.07) + 1.11 (0.02)χ（r2 = 0.99）来表示。这些发现与我们用于预测对静态稳定性影响的性质和程度的计算机模型结果一致，只是该模型显示，当座位位置变化大于我们所研究的范围时，这种关系会变成非线性。座位位置与动态前后稳定性（DSf和DSr，即引起瞬时倾倒所需的阈值速度，以米/秒为单位）之间的关系可以用方程DSf = 0.74 (0.01) - 0.041 (0.002)χ（r2 = 0.91）和DSr = 0.63 (0.01) + 0.030 (0.002)χ（r2 = 0.91）来表示。结果支持了我们的假设，并表明座位位置是轮椅稳定性的一个非常重要的决定因素。
