Transcript Kinetics versus kinematics for analyzing coordination
Biomechanics of Gait Initiation and Termination D. Gordon E. Robertson, PhD, FCSB Richard Smith. PhD, U. Sydney Nader Farapour, PhD, U. Tehran Natasha Kyle Joe Lynch
Biomechanics, Laboratory, School of Human Kinetics, University of Ottawa, Ottawa, Canada
Initiation of Gait: Events Quiet stance First toe-off (lead-leg) Second toe-off (trail-leg)
Results: Centres of Pressure trail line of gravity step 2 both
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Distance (m) Notice that as the combined centre of pressure
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lead moves backwards and towards the lead-leg the step 1 line of gravity proceeds forwards and towards the trail-leg. The line of gravity is outside the base of support shortly after the lead-leg lifts.
Biomechanics of Ramp Ascent and Descent D. Gordon E. Robertson, PhD, FCSB Robyn Wharf Andrew Post
Biomechanics, Laboratory, School of Human Kinetics, University of Ottawa, Ottawa, Canada
Ramp Ascent Study (Robyn Wharf)
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level, 3-, 6- and 9-degree inclines one step before ramp opposite leg on ramp 2 nd step on ramp
Force platforms
Ramp Ascent
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very few differences in the moments of force powers were more diagnostic
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level walking and 3 degrees almost same 6- and 9-degree inclines were sig. different
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hip
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Moments
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Powers
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Time (s, TO-TO)
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knee
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K2 0.5
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K4 K1 -1.5
K3 -2.0
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Time (s, TO-TO)
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ankle
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Time (s, TO-TO)
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Level 3-deg 6-deg 9-deg 0.2
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Time (s, TO-TO)
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Biomechanics of Stair Ascent and Descent D. Gordon E. Robertson, PhD, FCSB Tyler Cluff François D. Beaulieu Andrew Post Stefan Potozny
Biomechanics, Laboratory, School of Human Kinetics, University of Ottawa, Ottawa, Canada
Reflective markers
Motion Analysis Tools
Infrared cameras and EMGs Force platforms
Laboratory Stairs
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Step height = 20 cm Step tread = 30 cm Railings = 91 cm Height and tread are adjustable
Force platforms
Backwards Stair Descent Down Two Stairs Backwards to Landing
Discussion Benefits of Backwards Stair Descent
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Centre of pressure and centre of gravity are farther from edge of stairs
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If tripping occurs person falls into stairs not down stairs
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Person will be more inclined to use handrails
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Moments and powers were smaller than forwards but larger than walking
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No concentric ankle B-K amputees) power needed (e.g.,
Discussion Concerns with Backwards Stair Descent
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Problems with seeing next step landing and
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Unconventional compliance therefore may affect
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Does require railings people for most
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Irregular stairs may be problematic
Il Castillo, Chichen Itza, Mexico
Not the most dignified stair descent (5 point!)
Ballet Biomechanics
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grand jette
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jumping mechanics simulation pirouette
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fouette