Reduced Vertical Displacement Reverses Effect of Speed on Energy Expenditure
Advisor Information
Nicholas Stergiou
Location
UNO Criss Library, Room 231
Presentation Type
Oral Presentation
Start Date
7-3-2014 1:15 PM
End Date
7-3-2014 1:30 PM
Abstract
Human gait is an advanced process with biological and mechanical factors affecting efficiency. One controversial theory of efficiency is the displacement of the body’s center of mass (COM). Initially, the six determinants of gait suggested energy expenditure would be minimized by minimizing the body’s COM. Previously, we expanded on studies that disproved this theory with one major novelty. Specifically our experiment introduced a curved treadmill that has an arc shaped walking platform, similar to the inverted path of motion of the COM during walking. Thus, this design countered the arc of the center of mass, reducing vertical displacement of the COM. This made possible a more natural walking motion with reduced vertical movement as opposed to asking subjects to artificially alter their gait. Our previous study however used a self propelled curved treadmill and a motorized flat treadmill. To address this discrepancy, we motorized the curved treadmill, thus eliminating treadmill mechanics as a possible outside variable. Results were similar but did not exactly mirror our previous experimental results. Rather than VO2 rising at a constant rate for both treadmills, VO2 rose more on the flat treadmill than the curved. COM, similar to what we previously saw, increased more on the flat treadmill as speed increased than on the curved treadmill. Thus, it appears that as speeds increase, the excessive motion of the COM on the flat treadmill rapidly increases VO2. Our results support our previous work in that reduced vertical displacement does not coincide with reduced energy expenditure.
Reduced Vertical Displacement Reverses Effect of Speed on Energy Expenditure
UNO Criss Library, Room 231
Human gait is an advanced process with biological and mechanical factors affecting efficiency. One controversial theory of efficiency is the displacement of the body’s center of mass (COM). Initially, the six determinants of gait suggested energy expenditure would be minimized by minimizing the body’s COM. Previously, we expanded on studies that disproved this theory with one major novelty. Specifically our experiment introduced a curved treadmill that has an arc shaped walking platform, similar to the inverted path of motion of the COM during walking. Thus, this design countered the arc of the center of mass, reducing vertical displacement of the COM. This made possible a more natural walking motion with reduced vertical movement as opposed to asking subjects to artificially alter their gait. Our previous study however used a self propelled curved treadmill and a motorized flat treadmill. To address this discrepancy, we motorized the curved treadmill, thus eliminating treadmill mechanics as a possible outside variable. Results were similar but did not exactly mirror our previous experimental results. Rather than VO2 rising at a constant rate for both treadmills, VO2 rose more on the flat treadmill than the curved. COM, similar to what we previously saw, increased more on the flat treadmill as speed increased than on the curved treadmill. Thus, it appears that as speeds increase, the excessive motion of the COM on the flat treadmill rapidly increases VO2. Our results support our previous work in that reduced vertical displacement does not coincide with reduced energy expenditure.