Hamaoui Alain, Le Bozec Serge, Poupard Laurent, Bouisset Simon
Laboratoire Contrôle Moteur et Perception, UPRES EA 4042, Université Paris Sud, 91405 Orsay Cedex, France.
Gait Posture. 2007 Feb;25(2):199-204. doi: 10.1016/j.gaitpost.2006.03.012. Epub 2006 May 11.
This study investigated the effect of postural chain muscular stiffening on postural steadiness when it is rhythmically perturbed by respiration. It consisted of an analysis of centre of pressure (CP) displacements when constant sub-maximum pushing efforts were performed in a sitting posture. Muscular stiffness, assessed by surface electromyography (iEMG), was imposed at two controlled levels, using two intensities of pushing effort (20% and 40% of the maximum voluntary contraction: 20MVC and 40MVC). Lumbo-pelvic mobility was varied using two different support areas at the seat contact (100% and 30% of the ischio-femoral length: 100BP and 30BP). Respiratory disturbance to posture was varied using two respiratory rate conditions (quiet breathing (QB), which is the spontaneous rate, and fast breathing (FB) at a rate imposed by a metronome). The results demonstrated that an increased push effort was associated to a higher iEMG level, and induced greater mean deviation (X (p)) and sway path (SP) of antero-posterior CP displacements. It was concluded that postural muscle stiffness reduces postural steadiness. It was suggested that it could be related to a weaker compensation of respiratory disturbance to body posture.
本研究调查了姿势链肌肉僵硬在呼吸有节奏地干扰时对姿势稳定性的影响。该研究包括对坐姿下进行恒定次最大推压用力时压力中心（CP）位移的分析。通过表面肌电图（iEMG）评估的肌肉僵硬度，使用两种推压用力强度（最大自主收缩的20%和40%：20MVC和40MVC），被设定为两个受控水平。通过在座椅接触处使用两个不同的支撑面积（坐骨 - 股骨长度的100%和30%：100BP和30BP）来改变腰骶部活动度。通过两种呼吸频率条件（安静呼吸（QB），即自发频率，以及由节拍器设定的快速呼吸（FB））来改变对姿势的呼吸干扰。结果表明，增加推压用力与更高的iEMG水平相关，并导致前后CP位移的更大平均偏差（X（p））和摆动路径（SP）。研究得出结论，姿势性肌肉僵硬会降低姿势稳定性。研究表明，这可能与对身体姿势的呼吸干扰的较弱补偿有关。
