Metabolic and biomechanical effects of velocity and weight support using a lower-body positive pressure device during walking.
OBJECTIVE
To determine how changes in velocity and weight support affect metabolic power and ground reaction forces (GRFs) during walking using a lower-body positive pressure (LBPP) device. To find specific velocity and weight combinations that require similar aerobic demands but different peak GRFs.


METHODS
Repeated measures.


METHODS
University research laboratory.


METHODS
Healthy volunteer subjects (N=10).


METHODS
Subjects walked 1.00, 1.25, and 1.50 m/s on a force-measuring treadmill at normal weight (1.0 body weight [BW]) and at several fractions of BW (.25, .50, .75, .85 BW). The treadmill was enclosed within an LBPP apparatus that supported BW.


METHODS
Metabolic power, GRFs, and stride kinematics.


RESULTS
At faster velocities, peak GRFs and metabolic demands were greater. In contrast, walking at lower fractions of BW attenuated peak GRFs and reduced metabolic demand compared with normal weight walking. Many combinations of velocity and BW resulted in similar aerobic demands, yet walking faster with weight support lowered peak GRFs compared with normal weight walking.


CONCLUSIONS
Manipulating velocity and weight using an LBPP device during treadmill walking can reduce force yet maintain cardiorespiratory demand. Thus, LBPP treadmill training devices could be highly effective for rehabilitation after orthopedic injury and/or orthopedic procedures.
Department of Integrative Physiology, University of Colorado, Boulder, CO, USA. alenag@media.mit.edu
Alena M
AM
Grabowski
D000368:Aged; D000704:Analysis of Variance; D001696:Biomechanical Phenomena; D001835:Body Weight; D006233:Persons with Disabilities / Q000534:rehabilitation; D005260:Female; D006801:Humans; D016018:Least-Squares Analysis; D008297:Male; D010101:Oxygen Consumption / Q000502:physiology; D011312:Pressure; D015203:Reproducibility of Results; D016138:Walking / Q000502:physiology*; D016474:Weight-Bearing / Q000502:physiology*