Presentation Title

Metabolic Cost of Postural Control During a Perturbed Gait Task is Related to Gait Variability

Advisor Information

Sara Myers

Location

Milo Bail Student Center Ballroom

Presentation Type

Poster

Start Date

8-3-2013 1:00 PM

End Date

8-3-2013 4:00 PM

Abstract

When subjects walked on a curved treadmill compared to a standard flat treadmill, oxygen consumption (VO2) increased despite a reduction in vertical displacement of the center of mass (COM). We sought to determine the metabolic cost related to balance and the variability of the COM during walking. Five subjects walked at three speeds on a flat treadmill and a curved treadmill. VO2 was recorded and used to calculate basal metabolic rate (C1), the metabolic cost associated with maintaining balance (C2) and the metabolic cost associated with walking (C3). Dependent t-tests were used to compare C2 and C3. Correlations between C2, C3, and the variability of COM were done. Displacement, range and the largest Lyapunov exponent of the medial-lateral (ML) and anterior-posterior (AP) direction of the COM were calculated. Differences in these variables were examined using dependent t-tests. Subjects increased C2 values on the curved treadmill compared to the flat treadmill. They also showed reduced displacement and range with increased Lyapunov exponent of the COM displacement in both AP and ML directions on the curved treadmill. Correlation analysis revealed the Lyapunov exponent in the ML direction to be the most highly correlated with C2, with significant and positive correlations observed at all speeds. Medial-lateral standard deviation of COM displacement also showed a significant negative correlation with C2 at two speeds. This study showed that walking on a curved treadmill causes a more unpredictable gait in the ML direction and this is strongly related to increased metabolic cost.

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Mar 8th, 1:00 PM Mar 8th, 4:00 PM

Metabolic Cost of Postural Control During a Perturbed Gait Task is Related to Gait Variability

Milo Bail Student Center Ballroom

When subjects walked on a curved treadmill compared to a standard flat treadmill, oxygen consumption (VO2) increased despite a reduction in vertical displacement of the center of mass (COM). We sought to determine the metabolic cost related to balance and the variability of the COM during walking. Five subjects walked at three speeds on a flat treadmill and a curved treadmill. VO2 was recorded and used to calculate basal metabolic rate (C1), the metabolic cost associated with maintaining balance (C2) and the metabolic cost associated with walking (C3). Dependent t-tests were used to compare C2 and C3. Correlations between C2, C3, and the variability of COM were done. Displacement, range and the largest Lyapunov exponent of the medial-lateral (ML) and anterior-posterior (AP) direction of the COM were calculated. Differences in these variables were examined using dependent t-tests. Subjects increased C2 values on the curved treadmill compared to the flat treadmill. They also showed reduced displacement and range with increased Lyapunov exponent of the COM displacement in both AP and ML directions on the curved treadmill. Correlation analysis revealed the Lyapunov exponent in the ML direction to be the most highly correlated with C2, with significant and positive correlations observed at all speeds. Medial-lateral standard deviation of COM displacement also showed a significant negative correlation with C2 at two speeds. This study showed that walking on a curved treadmill causes a more unpredictable gait in the ML direction and this is strongly related to increased metabolic cost.