Abstract
This study assessed relationships between changes in walking pattern, caused by changes in walking speed and the application of a short leg brace (SLB), and energy efficiency. The subjects were 18 healthy men. Two foot switches and an accelerometer were applied to the subject's right leg for the determination of walking cycle. Energy efficiency during walking was obtained by the physiological cost index (PCI). The subjects were instructed to walk on a treadmill at walking speeds of 86 and 58 m/min. Another task was given to 11 of them; they were instructed to walk at 77 and 51 m/min with SLB applied to the left leg, and measurements similar to those without SLB were performed. The subjects were divided into the following three groups according to patterns for changes in walking cycle, which were observed when walking speed without SLB became slow: in Group I the subjects showed the increased ratio of time for the stance phase; in Group II the subjects showed the increased ratio of time for the heels to touch the ground; in Group III the subjects showed no changes in walking cycle. PCI was significantly lower during walking at 58 m/min than during walking at 86 m/min in Groups I and II, while PCI was unchanged in Group III. The subjects who were instructed to walk with SLB were divided into the following two groups according to patterns for changes in walking cycle, which were observed when walking speed with SLB became slow : in Group A the subjects showed the increased ratio of time for the stance phase; in Group B the subjects showed no changes in the ratio of time for stance phase. There was a significant difference in energy efficiency between Groups A and B, and PCI was significantly lower in Group A. The advantageous strategy for energy efficiency may vary in the presence of changes in walking circumstances such as applying SLB.
