Long-term unrestrained measurement of stride length and walking velocity utilizing a piezoelectric gyroscope

Long-term monitoring of stride length and walking velocity is considered to provide useful information for making decisions on treatment of patients with gait disabilities. The purpose of this study was to develop a device with the following design criteria: lightweight, easy attachment, little hindrance to the natural gait pattern, sufficient memory to record for one day, and practicality in clinical use. The prototype consists of a piezoelectric gyroscope, which detects angular velocity of the thigh of one leg in the sagittal plane, and a microprocessor-based maximum/minimum detector/data logger of a cyclic analog signal associated with the gait cycle. The accuracy of the device was evaluated in 20 normal subjects, seven above-the-knee (A/K) amputees, and ten hemiplegic patients, and relative accuracy within +/-15% was obtained, except for two special cases.