The subject was a 20 year old female college student. She was 1.63 meters tall and weighed 567.5 Newtons. In order to have the best viewing of the joint markers, she wore a spandex tank top and shorts. Since we were comparing gait in tennis shoes and in high-heeled shoes, we placed our joint markers on the greater tubercle of the humerus, the greater trochanter of the femur, the lateral epicondyle of the femur, the lateral malleoulus of the tibia, and the head of the fifth metatarsal of the foot.
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Figure 1. Joint markers in the normal gait (left) and the high-heel gait (right). The joint markers were placed on the greater tubercle of the humerous, the greater trochanter of the femur, the lateral epicondyle of the femur, the lateral maleoulus of the tibia, and the fifth metatarsal of the foot. | |
To collect our data we used a racquetball court in the Central Campus Recreation Building at the University of Michigan. The camera was a Hi-8 video recorder, which recorded at 30 frames a second. The subject was told to walk naturally from one end of the court to the other so that the gait we analyzed would be the subject's normal gait. To choose the trials for analysis, we determined which film segments were the most characteristic of the subject's typical gait in tennis shoes and high-heels. One gait cycle began with the heel strike of the right foot, and ended with the next subsequent heel strike.
The videotaped images were digitized at 30 frames per second using FusionRecorder on Mactintosh computers in the New Media Center at the University of Michigan. The digital video files were trimmed using MoviePlayer so that the data files contained only the frames between the start and end of the movements. A custom quality (QT->PICT) was used to convert the Quicktime movie filed into a series of individual frame files in PICT format for use with the Motion Plus software. Shoulder, hip, knee, ankle, and foot were digitized using Motion Capture. Joint marker coordinate data were exported in spreadsheet format to Excel for biomechanical analysis using MotionAnalyze.
