Effect of walking speed on lower extremity weight bearing during partial immersion
Many physical rehabilitation programs use water as a medium for treatment; however, the effect of walking speed in the weight bearing forces in the lower extremity during walking in water has not been fully investigated. The purpose of this study was to determine the effect of walking speed on weight bearing through the lower extremities during standing, slow walking, and fast walking while the body is partially immersed in water. Initially, a pilot study was performed to determine the proper parameters for the walking speeds when subjects were walking in water. The primary study consisted of 32 subjects, 5 males and 27 females, ranging in age from 22 to 61. Subjects' body composition was measured using the sum of three skinfold method. Subjects were grouped according to body fat, the LOW group having percent body fat less than 19.9% and the HIGH group being greater than 23%. Subjects were weighed on land and in water at two anatomic levels, using a digital bathroom scale that had been modified for use in water. The scale was inserted in a 15-foot platform constructed of plywood and PVC pipe. The subjects walked across the scale at two speeds, Normal and Fast, for seven trials. The results of this study show that there is significant difference in weight bearing between HIGH and LOW fat subjects, that walking speed had a significant effect on weight bearing, that there is a significant difference between weight bearing at the two levels of immersion, and that there is a significant interaction between walking speed and levels of immersion. These results led to the conclusions that LOW fat subjects have higher weight bearing, weight bearing at the ASIS level is greater than at XIPHI, weight bearing is higher when the subject was walking, and the increase in weight bearing from standing to fast walking was greater at XIPHI than at ASIS. This information will help provide the clinician with valuable guidelines for weight bearing during rehabilitation activities.