Duclos Cyril, Roll Régine, Kavounoudias Anne, Mongeau Jean-Philippe, Roll Jean-Pierre, Forget Robert
Laboratoire de Neurobiologie Humaine, UMR/CNRS 6149, Aix-Marseille Universités, Centre St. Charles, Pole 3C, Case B, 3, Place Victor Hugo, 13331 Marseille Cedex 03, France.
J Electromyogr Kinesiol. 2009 Aug;19(4):e214-22. doi: 10.1016/j.jelekin.2008.04.007. Epub 2008 May 22.
Lower leg amputation generally induces asymmetrical weight-bearing, even after rehabilitation treatment is completed. This is detrimental to the amputees' long term quality of life. In particular, increasing strains on joint surfaces that receive additional weight load causes back and leg pain, premature wear and tear and arthritis. This pilot study was designed to determine whether subjects with lower leg amputation experience postural post-effects after muscle contraction, a phenomenon already observed in healthy subjects, and whether this could improve the weight-bearing on their prosthesis. Fifteen subjects with a unilateral lower leg amputation and 17 control subjects volunteered to participate in this study. Centre of pressure (CP) position was recorded during standing posture, under eyes closed and open conditions. Recordings were carried out before the subjects performed a 30-s voluntary isometric lateral neck muscle contraction, and again 1 and 4 min after the contraction. Postural post-effects characterized by CP shift, occurred in the medio-lateral plane in the majority of the amputated (7/15 eyes closed, 9/15 eyes open) and control (9/17 eyes closed, 11/17 eyes open) subjects after the contraction. Half of these subjects had a CP shift towards the side of the contraction and the other half towards the opposite side. In four amputated subjects tested 3 months apart, shift direction remained constant. These postural changes occurred without increase in CP velocity. Thus, a 30-s voluntary isometric contraction can change the standing posture of persons with lower leg amputation. The post-effects might result from the adaptation of the postural frame of reference to the proprioceptive messages associated with the isometric contraction.
小腿截肢通常会导致不对称负重，即使在康复治疗完成后也是如此。这对截肢者的长期生活质量不利。特别是，承受额外重量负荷的关节表面上的应变增加会导致背部和腿部疼痛、过早磨损和关节炎。这项初步研究旨在确定小腿截肢患者在肌肉收缩后是否会经历姿势后效应（这一现象已在健康受试者中观察到），以及这是否可以改善他们假肢上的负重。15名单侧小腿截肢患者和17名对照受试者自愿参与了这项研究。在闭眼和睁眼站立姿势期间记录压力中心（CP）位置。记录在受试者进行30秒的自愿等长外侧颈部肌肉收缩之前进行，收缩后1分钟和4分钟再次记录。以CP移位为特征的姿势后效应在大多数截肢（7/15闭眼，9/15睁眼）和对照（9/17闭眼，11/17睁眼）受试者收缩后的中外侧平面出现。这些受试者中有一半的CP向收缩侧移位，另一半向相反侧移位。在相隔3个月测试的4名截肢受试者中，移位方向保持不变。这些姿势变化在CP速度没有增加的情况下发生。因此，30秒的自愿等长收缩可以改变小腿截肢者的站立姿势。这种后效应可能是由于姿势参考框架适应了与等长收缩相关的本体感觉信息。
