Shenoy Swati, Aruin Alexander S
Department of Physical Therapy, University of Illinois at Chicago, IL 60612, USA.
Motor Control. 2007 Oct;11(4):309-21. doi: 10.1123/mcj.11.4.309.
The objective of this study was to determine if a forward-tilted seat and the resultant semi-kneeling body position associated with sitting on the Balans Multi Chair (BMC) affect postural control in sitting. Nine healthy subjects were seated on either the BMC or a regular (REG) chair with their arms extended. They were instructed to induce self-initiated body perturbations in four different directions by exerting brief pulses of force against a stationary frame positioned in front of them. Electromyographic (EMG) activities of trunk and leg muscles were recorded before and during the perturbations. The results show that sitting on both types of chairs was associated with anticipatory activation of trunk and upper leg muscles. In contrast, anticipatory activation of distal muscles was observed while sitting only on the REG chair and was absent while sitting on the BMC. The outcome of the study suggests that although the forward-tilting seat and semi-kneeling body position might help in preserving a normal lordosis, it is not associated with anticipatory activation of lower leg muscles, which might reduce the ability of an individual to counteract self-initiated body perturbations. These findings stress the important role of chair designs in the control of sitting posture.
本研究的目的是确定前倾座椅以及坐在巴兰斯多功能椅（BMC）上所产生的半跪身体姿势是否会影响坐姿时的姿势控制。九名健康受试者分别坐在BMC或普通（REG）椅子上，双臂伸展。他们被要求通过对位于身前的固定框架施加短暂的力脉冲，在四个不同方向上引发自主的身体扰动。在扰动之前和期间记录躯干和腿部肌肉的肌电图（EMG）活动。结果表明，坐在两种类型的椅子上都与躯干和大腿上部肌肉的预期激活有关。相比之下，仅坐在REG椅子上时观察到远端肌肉的预期激活，而坐在BMC上时则没有。研究结果表明，尽管前倾座椅和半跪身体姿势可能有助于保持正常的脊柱前凸，但它与小腿肌肉的预期激活无关，这可能会降低个体抵消自主身体扰动的能力。这些发现强调了椅子设计在坐姿控制中的重要作用。
