1. 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 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

2. Initiation of Gait: Events Quiet stance First toe-off (lead-leg) First toe-off (lead-leg) Second toe-off (trail-leg) Second toe-off (trail-leg)

3. Results: Centres of Pressure step 1 step 2 lead trail both line of gravity Notice that as the combined centre of pressure moves backwards and towards the lead-leg the 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.

4. 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 D. Gordon E. Robertson, PhD, FCSB Robyn Wharf Andrew Post Biomechanics, Laboratory, School of Human Kinetics, University of Ottawa, Ottawa, Canada

5. Ramp Ascent Study (Robyn Wharf) level, 3-, 6- and 9-degree inclines one step before ramp opposite leg on ramp 2 nd step on ramp Force platforms

6. Ramp Ascent very few differences in the moments of force powers were more diagnostic level walking and 3- degrees almost same 6- and 9-degree inclines were sig. different hip knee ankle MomentsPowers

7. 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 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

8. Motion Analysis Tools Reflective markers Force platforms Infrared cameras and EMGs

9. Step height = 20 cm Step tread = 30 cm Railings = 91 cm Height and tread are adjustable Force platforms Laboratory Stairs

10. Backwards Stair Descent Down Two Stairs Backwards to Landing

11. Discussion Centre of pressure and centre of gravity are farther from edge of stairs If tripping occurs person falls into stairs not down stairs Person will be more inclined to use handrails Moments and powers were smaller than forwards but larger than walking No concentric ankle power needed (e.g., B-K amputees) Benefits of Backwards Stair Descent

12. Concerns with Backwards Stair Descent Discussion Problems with seeing next step and landing Unconventional therefore may affect compliance Does require railings for most people Irregular stairs may be problematic

13. Il Castillo, Chichen Itza, Mexico Not the most dignified stair descent (5 point!)

14. Ballet Biomechanics grand jette –jumping mechanics –simulation pirouette fouette