Hsu M, Nielsen DH, Lin S, Yack J; Graduate Program in Physical Therapy and Rehabilitation Science, University of Iowa, Iowa City, USA. mjhsu@ym.edu.tw.

PURPOSE: The gait of an individual with transtibial amputation requires more energy cost, has higher relative exercise intensity, and is less efficient, compared to individuals with nonpathological gait. The energy storing-releasing prosthetic feet, the Otto Bock C-Walk (C-Walk) and the Flex Foot (FF), are speculated to provide better push-off and thus, improve gait performance compared to the traditional Solid Ankle Cushion Heel (SACH) prosthetic foot. However, no research has been done to substantiate this conjecture. The purpose of this study was to investigate foottype differences of the C-Walk, the FF, and the SACH in individuals with transtibial amputation, based on physiological [energy cost, relative exercise intensity, gait efficiency, and rating of perceived exertion (RPE)] comparisons. SUBJECTS: Eight male subjects with transtibial amputation were recruited. METHODS: A two-factor (speed and type of prosthesis) repeated measures design involving multiple speed treadmill walking (53.64, 67.05, 80.46, 93.87, and 107.28 m/min) was employed. A Medigraphics Cardio2 metabolic cart and an ECG radiotelemetry system were used for oxygen uptake and heart rate measurement, respectively. Relative exercise intensity was expressed as a percentage of age predicted maximum heart rate (%APMHR). The 6.19 Borg scale was used for RPE measurements. ANALYSIS: Two-way analysis of variance (ANOVA) was used to analyze foottype differences for each physiological variable. RESULTS: Our results revealed that the C-Walk had a trend of improved physiological responses compared to the SACH; however, no foottype differences were statistically significant. Compared to the C-Walk and the SACH, the FF showed no significant differences in energy cost and gait efficiency, but significantly lower %APMHR and RPE values. CONCLUSIONS: The results suggested that the FF may be more beneficial to physically active individuals with transtibial amputation, compared to the C-Walk and the SACH. RELEVANCE: The results of this study provided information on foottype characteristics based on physiological aspects, which should help prosthetists and physical therapists with their recommendations for selecting appropriate prosthetic feet to individuals with transtibial amputation. FUNDING SOURCE: Otto-Bock Orthopedic Industry, Minneapolis, USA./P>

Copyright 2004 by the American Physical Therapy Association

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