Schultz A B, Alexander N B, Ashton-Miller J A
Department of Mechanical Engineering and Applied Mechanics. University of Michigan, Ann Arbor 48109-2125.
J Biomech. 1992 Dec;25(12):1383-91. doi: 10.1016/0021-9290(92)90052-3.
Quantification of the biomechanical factors that underlie the inability to rise from a chair can help explain why this disability occurs and can aid in the design of chairs and of therapeutic intervention programs. Experimental data collected earlier from 17 young adult and two groups of elderly subjects, 23 healthy and 11 impaired, rising from a standard chair under controlled conditions were analyzed using a planar biomechanical model. The joint torque strength requirements and the location of the floor reaction force at liftoff from the seat in the different groups and under several conditions were calculated. Analyses were also made of how body configurations and the use of hand force affect these joint torques and reaction locations. In all three groups, the required torques at liftoff were modest compared to literature data on voluntary strengths. Among the three groups rising with the use of hands, at the time of liftoff from the seat, the impaired old subjects, on an average, placed the reaction force the most anterior, the healthy old subjects placed it intermediately and the young subjects placed it the least anterior, within the foot support area. Moreover, the results suggest that, at liftoff, all subjects placed more importance on locating the floor reaction force to achieve acceptable postural stability than on diminishing the magnitudes of the needed joint muscle strengths.
对导致无法从椅子上起身的生物力学因素进行量化，有助于解释这种残疾为何会发生，并有助于椅子和治疗干预方案的设计。早期收集的实验数据来自17名年轻成年人以及两组老年受试者，其中23名健康，11名有损伤，他们在受控条件下从标准椅子上起身，使用平面生物力学模型对这些数据进行了分析。计算了不同组在几种条件下离座起身时的关节扭矩强度要求以及地面反作用力的位置。还分析了身体形态和手部力量的使用如何影响这些关节扭矩和反作用力位置。与关于自愿力量的文献数据相比，所有三组在离座起身时所需的扭矩都较小。在三组使用手部起身的受试者中，在离座起身时，受损老年受试者平均将反作用力放置得最靠前，健康老年受试者放置在中间位置，年轻受试者放置得最靠后，均在足部支撑区域内。此外，结果表明，在离座起身时，所有受试者更重视确定地面反作用力的位置以实现可接受的姿势稳定性，而不是减小所需关节肌肉力量的大小。
