Mâsse L C, Lamontagne M, O'Riain M D
School of Human Kinetics, University of Ottawa, Ontario, Canada.
J Rehabil Res Dev. 1992 Summer;29(3):12-28. doi: 10.1682/jrrd.1992.07.0012.
The pattern of propulsion was investigated for five male paraplegics in six seating positions. The positions consisted of a combination of three horizontal rear-wheel positions at two seating heights on a single-purpose-built racing wheelchair. To simulate wheelchair propulsion in the laboratory, the wheelchair was mounted on high rotational inertia rollers. For three trials at each seating position, the subjects propelled the designed wheelchair at 60 percent of their maximal speed, which was determined at the beginning of the test session. At each trial, the propulsion technique of the subject was filmed at 50 Hz with a high-speed camera for one cycle, and the raw electromyographic (EMG) signal of the biceps, brachii, triceps brachii, pectoralis major, deltoid anterior, and deltoid posterior muscles were simultaneously recorded for three consecutive cycles. The digitized film data were used to compute the angular kinematics of the upper body, while the EMG signals were processed to yield the linear envelope (LE EMG) and the integrated EMG (IEMG) of each muscle. The kinematic analysis revealed that the joint motions of the upper limbs were smoother for the Low positions-since they reached extension in a sequence (wrist, shoulder, and elbow), when compared to the High positions. Also, the elbow angular velocity slopes were found to be less abrupt for the Backward-Low position. It was observed that in lowering the seat position, less IEMG was recorded and the degrees of contact were lengthened. Among the seat positions evaluated, the Backward-Low position had the lowest overall IEMG and the Middle-Low position had the lowest pushing frequency. It was found that a change in seat position caused more variation in the IEMG for the triceps brachii, pectoralis major, and deltoid posterior. The trunk angular momentum was not found to be affected by a change in seat position which may be related to the variability among the subject's technique of propulsion or to a posture compensation.
研究了五名男性截瘫患者在六个坐姿下的推进模式。这些姿势由在一台专用竞赛轮椅上两个座位高度的三个水平后轮位置组合而成。为了在实验室中模拟轮椅推进，轮椅被安装在高转动惯量的滚轮上。在每个坐姿下进行三次试验，受试者以其最大速度的60%推动设计好的轮椅，最大速度在测试开始时确定。在每次试验中，用高速摄像机以50Hz的频率拍摄受试者一个周期的推进技术，同时连续三个周期记录肱二头肌、肱三头肌、胸大肌、三角肌前束和三角肌后束的原始肌电图（EMG）信号。数字化的电影数据用于计算上半身的角运动学，而EMG信号经过处理以得到每块肌肉的线性包络（LE EMG）和积分肌电图（IEMG）。运动学分析表明，与高位姿势相比，低位姿势下上肢的关节运动更平滑，因为它们按顺序（手腕、肩部和肘部）达到伸展。此外，发现后低位姿势的肘部角速度斜率不那么陡峭。观察到，降低座位位置时，记录到的IEMG较少，接触程度延长。在评估的座位位置中，后低位姿势的总体IEMG最低，中低位姿势的推频最低。发现座位位置的改变导致肱三头肌、胸大肌和三角肌后束的IEMG变化更大。未发现躯干角动量受座位位置变化的影响，这可能与受试者推进技术的变异性或姿势补偿有关。
