Biomechanics of Gait Initiation and Termination

Biomechanics of Gait Initiation and Termination

D. Gordon E. Robertson, PhD, FCSBRichard Smith. PhD, U. SydneyNader Farapour, PhD, U. TehranNatasha KyleJoe Lynch

Biomechanics, Laboratory,School of Human Kinetics,University of Ottawa, Ottawa, Canada

D. Gordon E. Robertson, PhD, FCSBRichard Smith. PhD, U. SydneyNader Farapour, PhD, U. TehranNatasha KyleJoe Lynch

Biomechanics, Laboratory,School of Human Kinetics,University of Ottawa, Ottawa, Canada

Initiation of Gait: Events

Quiet stanceQuiet stance First toe-off(lead-leg)

First toe-off(lead-leg)

Second toe-off(trail-leg)

Second toe-off(trail-leg)

Results:Centres of Pressure

-0.1

0.0

0.1

0.2

0.3

-0.7 -0.6 -0.5 -0.4 -0.3 -0.2 -0.1 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2.0

Distance (m)

step 1step 1

step 2step 2

leadlead

trailtrail

bothboth

line of gravityline 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.

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.

Biomechanics of Ramp Ascent and Descent

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

Ramp Ascent Study(Robyn Wharf)

• level, 3-, 6- and 9-degree inclines

• one step before ramp

• opposite leg on ramp

• 2nd step on ramp

Force platforms

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

-2.0

-1.5

-1.0

-0.5

0.0

0.5

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3

Time (s, TO-TO)

Mome

nt of

force

(N.m

/kg)

-1.0

-0.5

0.0

0.5

1.0

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3

Time (s, TO-TO)

Mome

nt of

force

(N.m

/kg)

-1.0

-0.5

0.0

0.5

1.0

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3

Time (s, TO-TO)

Mome

nt of

force

(N.m

/kg)

-1.0

-0.5

0.0

0.5

1.0

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3

Time (s, TO-TO)

Powe

r (W/

kg)

H1

H2

H3H3

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3

Time (s, TO-TO)

Powe

r (W/

kg)

K4 K1

K2

K0

K3

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3

Time (s, TO-TO)

Powe

r (W/

kg)

Level

3-deg

6-deg

9-deg

A1

A2

hip

knee

ankle

Moments Powers

Biomechanics of Stair Ascent and Descent

Biomechanics of Stair Ascent and Descent

D. Gordon E. Robertson, PhD, FCSBTyler CluffFrançois D. BeaulieuAndrew PostStefan Potozny

Biomechanics, Laboratory,School of Human Kinetics,University of Ottawa, Ottawa, Canada

D. Gordon E. Robertson, PhD, FCSBTyler CluffFrançois D. BeaulieuAndrew PostStefan Potozny

Biomechanics, Laboratory,School of Human Kinetics,University of Ottawa, Ottawa, Canada

Motion Analysis Tools

Reflective markers

Force platforms

Infrared camerasand EMGs

• Step height = 20 cm

• Step tread = 30 cm

• Railings = 91 cm

• Height and tread are adjustable

Force platformsForce platforms

Laboratory Stairs

Backwards Stair Descent

Down Two Stairs Backwards to Landing

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

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

Il Castillo, Chichen Itza, Mexico

Not the most dignified stair descent (5 point!)

Ballet Biomechanics

• grand jette– jumping mechanics

– simulation

• pirouette

• fouette