Cooper Rory A, DiGiovine Carmen P, Boninger Michael L, Shimada Sean D, Koontz Alicia M, Baldwin Mark A
Human Engineering Research Laboratories, VA Pittsburgh Healthcare System, PA 15206, USA.
J Rehabil Res Dev. 2002 May-Jun;39(3):323-36.
Wheelchair locomotion is an important form of mobility for many individuals with spinal cord injury. However, manual wheelchair propulsion can lead to upper-limb pain and can be very inefficient. This has led investigators to apply biomechanics to the study of wheelchair use. The objectives of this study were (1) to determine the frequency content of the motion of both hands during two speeds of wheelchair propulsion, (2) to obtain the filter frequencies necessary to remove noise from wheelchair motion data, and (3) to provide signal-to-noise ratio data for wheelchair kinematics. The participants in this study were a random sample of manual wheelchair users with paraplegia caused by spinal cord injury. Subjects propelled their personal wheelchairs on a computer-controlled dynamometer at speeds of 0.9 m/s and 1.8 m/s. Motion data were collected at 60 Hz with the use of a commercial infrared marker-based system. The main outcome measures were arm motions and noise frequency spectra, filter cutoff frequencies, and signal-to-noise ratio. Our results indicate that there is no useful signal power above 6 Hz during manual wheelchair propulsion at the speeds that we analyzed. In many cases, there was no useful signal power above 4 Hz. This would indicate that the frequency content of manual wheelchair propulsion is similar to that of human gait. The mean signal-to-noise ratio varied from a high of 91 dB to a low of 21.8 dB. The signal-to-noise ratio was greatest in the x direction (along the line of progression) and lowest in the z direction (medial-lateral). Manual wheelchair propulsion kinematic data should be low-pass filtered at approximately 6 Hz for speeds at or below 1.8 m/s. The data presented in the archival literature appear to have been filtered at an appropriate frequency.
对于许多脊髓损伤患者而言，轮椅移动是一种重要的出行方式。然而，手动轮椅推进可能会导致上肢疼痛，且效率非常低下。这促使研究人员将生物力学应用于轮椅使用的研究中。本研究的目的是：（1）确定两种轮椅推进速度下双手运动的频率成分；（2）获取从轮椅运动数据中去除噪声所需的滤波频率；（3）提供轮椅运动学的信噪比数据。本研究的参与者是因脊髓损伤导致截瘫的手动轮椅使用者的随机样本。受试者在计算机控制的测力计上以0.9米/秒和1.8米/秒的速度推动自己的轮椅。使用基于商用红外标记的系统以60赫兹的频率收集运动数据。主要测量指标为手臂运动、噪声频谱、滤波截止频率和信噪比。我们的结果表明，在我们分析的速度下，手动轮椅推进过程中6赫兹以上没有有用的信号功率。在许多情况下，4赫兹以上没有有用的信号功率。这表明手动轮椅推进的频率成分与人类步态相似。平均信噪比从最高的91分贝到最低的21.8分贝不等。信噪比在x方向（沿行进方向）最大，在z方向（内侧-外侧）最小。对于速度为1.8米/秒及以下的手动轮椅推进运动学数据，应在约6赫兹处进行低通滤波。存档文献中呈现的数据似乎已在适当的频率下进行了滤波。
