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Two-segment Model of the Foot for Gait Analysis D. Gordon E. Robertson, Ph.D. Alison Cronin...
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![Page 1: Two-segment Model of the Foot for Gait Analysis D. Gordon E. Robertson, Ph.D. Alison Cronin Biomechanics Laboratory, School of Human Kinetics, University.](https://reader036.fdocuments.us/reader036/viewer/2022062306/5a4d1b4f7f8b9ab0599a6f15/html5/thumbnails/1.jpg)
Two-segment Model of the Footfor Gait Analysis
D. Gordon E. Robertson, Ph.D.Alison Cronin
Biomechanics Laboratory,School of Human Kinetics,University of Ottawa, Ottawa, CANADA
![Page 2: Two-segment Model of the Foot for Gait Analysis D. Gordon E. Robertson, Ph.D. Alison Cronin Biomechanics Laboratory, School of Human Kinetics, University.](https://reader036.fdocuments.us/reader036/viewer/2022062306/5a4d1b4f7f8b9ab0599a6f15/html5/thumbnails/2.jpg)
Introduction
• Stephanyshn & Nigg (1997) showed negative work done by MP plantar flexors for running
• used EMED insole pressure system to partition floor reactions into two components
• pressure systems have no ability to distinguish components of a force only the magnitude of the resultant
• a single force platform cannot distinguish among several applied forces
• force plates computes a single resultant force--its components and centre of pressure
![Page 3: Two-segment Model of the Foot for Gait Analysis D. Gordon E. Robertson, Ph.D. Alison Cronin Biomechanics Laboratory, School of Human Kinetics, University.](https://reader036.fdocuments.us/reader036/viewer/2022062306/5a4d1b4f7f8b9ab0599a6f15/html5/thumbnails/3.jpg)
Solution
• use two force platforms• Gerber & Stuessi (1987)
developed equations to combine multiple force plates (available at www.health.uottawa.ca/
biomech/csb/archives/ kistler.pdf)
• arrange plates end-to-end
![Page 4: Two-segment Model of the Foot for Gait Analysis D. Gordon E. Robertson, Ph.D. Alison Cronin Biomechanics Laboratory, School of Human Kinetics, University.](https://reader036.fdocuments.us/reader036/viewer/2022062306/5a4d1b4f7f8b9ab0599a6f15/html5/thumbnails/4.jpg)
Solution
• subject lands foot across both plates
• in most cases little or no force occurs midstance
• can evaluate the subject using one or two ground reaction forces
![Page 5: Two-segment Model of the Foot for Gait Analysis D. Gordon E. Robertson, Ph.D. Alison Cronin Biomechanics Laboratory, School of Human Kinetics, University.](https://reader036.fdocuments.us/reader036/viewer/2022062306/5a4d1b4f7f8b9ab0599a6f15/html5/thumbnails/5.jpg)
Methods
• two male subjects• video taped at 60 fields/second• five trials of stance phase of walking at self-
selected speed• ground reaction forces sampled at 250 Hz
from two Kistler force plates• two conditions:
– one segment foot– two segment foot
![Page 6: Two-segment Model of the Foot for Gait Analysis D. Gordon E. Robertson, Ph.D. Alison Cronin Biomechanics Laboratory, School of Human Kinetics, University.](https://reader036.fdocuments.us/reader036/viewer/2022062306/5a4d1b4f7f8b9ab0599a6f15/html5/thumbnails/6.jpg)
Free-body diagram of one-segment foot
![Page 7: Two-segment Model of the Foot for Gait Analysis D. Gordon E. Robertson, Ph.D. Alison Cronin Biomechanics Laboratory, School of Human Kinetics, University.](https://reader036.fdocuments.us/reader036/viewer/2022062306/5a4d1b4f7f8b9ab0599a6f15/html5/thumbnails/7.jpg)
Free-body diagrams oftwo-segment foot
![Page 8: Two-segment Model of the Foot for Gait Analysis D. Gordon E. Robertson, Ph.D. Alison Cronin Biomechanics Laboratory, School of Human Kinetics, University.](https://reader036.fdocuments.us/reader036/viewer/2022062306/5a4d1b4f7f8b9ab0599a6f15/html5/thumbnails/8.jpg)
Methods
• mechanical energy and rate of change of energy computed (E/t)
• inverse dynamics to calculate net forces (F) and moments of force (M)
• force powers: Pf = F . v• moment powers: Pm = M • total power: Pt = Pf + Pm• power imbalance:Pi = E/t - Pt
![Page 9: Two-segment Model of the Foot for Gait Analysis D. Gordon E. Robertson, Ph.D. Alison Cronin Biomechanics Laboratory, School of Human Kinetics, University.](https://reader036.fdocuments.us/reader036/viewer/2022062306/5a4d1b4f7f8b9ab0599a6f15/html5/thumbnails/9.jpg)
Results (subject 1)
• pause to show animation
![Page 10: Two-segment Model of the Foot for Gait Analysis D. Gordon E. Robertson, Ph.D. Alison Cronin Biomechanics Laboratory, School of Human Kinetics, University.](https://reader036.fdocuments.us/reader036/viewer/2022062306/5a4d1b4f7f8b9ab0599a6f15/html5/thumbnails/10.jpg)
Ang. velocity, moment and power of the ankle joint
(WN01GR)
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8Time (s)
-500.
-250.
0.
250.
-100.
0.
100.
-10.
0.
10.
Pow
er (W
)
M
omen
t (N
.m)
Ang
ular
vel
. (/s
)
Trial: WN01GRAng. vel.Net momentPower
IFS IHO ITO
Dorsiflexing
Plantar flexingDorsiflexor
Plantar flexorConcentric
Eccentric
![Page 11: Two-segment Model of the Foot for Gait Analysis D. Gordon E. Robertson, Ph.D. Alison Cronin Biomechanics Laboratory, School of Human Kinetics, University.](https://reader036.fdocuments.us/reader036/viewer/2022062306/5a4d1b4f7f8b9ab0599a6f15/html5/thumbnails/11.jpg)
Ang. velocity, moment and power of the ankle joint
(WN01GR2)
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8Time (s)
-500.
-250.
0.
250.
-100.
0.
100.
-10.
0.
10.
Pow
er (W
)
M
omen
t (N
.m)
Ang
ular
vel
. (/s
)
Trial: WN01GR2Ang. vel.Net momentPower
IFS IHO ITO
Dorsiflexing
Plantar flexingDorsiflexor
Plantar flexorConcentric
Eccentric
![Page 12: Two-segment Model of the Foot for Gait Analysis D. Gordon E. Robertson, Ph.D. Alison Cronin Biomechanics Laboratory, School of Human Kinetics, University.](https://reader036.fdocuments.us/reader036/viewer/2022062306/5a4d1b4f7f8b9ab0599a6f15/html5/thumbnails/12.jpg)
Ang. velocity, moment and power of the MP joint
(WN01GR2)
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8Time (s)
-500.
-250.
0.
250.
-100.
0.
100.
-10.
0.
10.
Pow
er (W
)
M
omen
t (N
.m)
Ang
ular
vel
. (/s
)
Trial: WN01GR2Ang. vel.Net momentPower
IFS IHO ITO
Dorsiflexing
Plantar flexingDorsiflexor
Plantar flexorConcentric
Eccentric
![Page 13: Two-segment Model of the Foot for Gait Analysis D. Gordon E. Robertson, Ph.D. Alison Cronin Biomechanics Laboratory, School of Human Kinetics, University.](https://reader036.fdocuments.us/reader036/viewer/2022062306/5a4d1b4f7f8b9ab0599a6f15/html5/thumbnails/13.jpg)
Foot powers(WN01GR)
0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70Time (seconds)
-2000.
-1500.
-1000.
-500.
0.
500.
1000.
1500.
2000.
Pow
er (W
)
Trial: WN01GRFloor powerForce powerMoment powerTotal powerEnergy ratePower imbalance
IFS IHO ITO
![Page 14: Two-segment Model of the Foot for Gait Analysis D. Gordon E. Robertson, Ph.D. Alison Cronin Biomechanics Laboratory, School of Human Kinetics, University.](https://reader036.fdocuments.us/reader036/viewer/2022062306/5a4d1b4f7f8b9ab0599a6f15/html5/thumbnails/14.jpg)
0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70Time (seconds)
-2000.
-1500.
-1000.
-500.
0.
500.
1000.
1500.
2000.
Pow
er (W
)
Trial: WN01GR2Floor powerMP force powerMP moment powerFf total powerFf energy rateFf power imbalance
IFS IHO ITO
Forefoot powers(WN01GR2)
![Page 15: Two-segment Model of the Foot for Gait Analysis D. Gordon E. Robertson, Ph.D. Alison Cronin Biomechanics Laboratory, School of Human Kinetics, University.](https://reader036.fdocuments.us/reader036/viewer/2022062306/5a4d1b4f7f8b9ab0599a6f15/html5/thumbnails/15.jpg)
Rearfoot powers(WN01GR2)
0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70Time (seconds)
-2000.
-1500.
-1000.
-500.
0.
500.
1000.
1500.
2000.
Pow
er (W
)
Trial: WN01GR2MP force powerMP moment powerAnkle force powerAnkle moment powerRf total powerRf energy rateRf power imbalance
IFS IHO ITO
![Page 16: Two-segment Model of the Foot for Gait Analysis D. Gordon E. Robertson, Ph.D. Alison Cronin Biomechanics Laboratory, School of Human Kinetics, University.](https://reader036.fdocuments.us/reader036/viewer/2022062306/5a4d1b4f7f8b9ab0599a6f15/html5/thumbnails/16.jpg)
Results (subject 2)
• pause to show animation
![Page 17: Two-segment Model of the Foot for Gait Analysis D. Gordon E. Robertson, Ph.D. Alison Cronin Biomechanics Laboratory, School of Human Kinetics, University.](https://reader036.fdocuments.us/reader036/viewer/2022062306/5a4d1b4f7f8b9ab0599a6f15/html5/thumbnails/17.jpg)
Ang. velocity, moment and power of the ankle joint
(WN01JS)
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0Time (s)
-500.
-250.
0.
250.
-100.
0.
100.
-10.
0.
10.
Pow
er (W
)
M
omen
t (N
.m)
Ang
ular
vel
. (/s
)
Trial: WN01JSAng. vel.Net momentPower
IFS IHO ITO
Dorsiflexing
Plantar flexingDorsiflexor
Plantar flexorConcentric
Eccentric
![Page 18: Two-segment Model of the Foot for Gait Analysis D. Gordon E. Robertson, Ph.D. Alison Cronin Biomechanics Laboratory, School of Human Kinetics, University.](https://reader036.fdocuments.us/reader036/viewer/2022062306/5a4d1b4f7f8b9ab0599a6f15/html5/thumbnails/18.jpg)
Ang. velocity, moment and power of the MP joint
(WN01JS2)
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0Time (s)
-500.
-250.
0.
250.
-100.
0.
100.
-10.
0.
10.
Pow
er (W
)
M
omen
t (N
.m)
Ang
ular
vel
. (/s
)
Trial: WN01JS2Ang. vel.Net momentPower
IFS IHO ITO
Dorsiflexing
Plantar flexingDorsiflexor
Plantar flexorConcentric
Eccentric
![Page 19: Two-segment Model of the Foot for Gait Analysis D. Gordon E. Robertson, Ph.D. Alison Cronin Biomechanics Laboratory, School of Human Kinetics, University.](https://reader036.fdocuments.us/reader036/viewer/2022062306/5a4d1b4f7f8b9ab0599a6f15/html5/thumbnails/19.jpg)
Ang. velocity, moment and power of the ankle joint
(WN01JS2)
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0Time (s)
-500.
-250.
0.
250.
-100.
0.
100.
-10.
0.
10.
Pow
er (W
)
M
omen
t (N
.m)
Ang
ular
vel
. (/s
)
Trial: WN01JS2Ang. vel.Net momentPower
IFS IHO ITO
Dorsiflexing
Plantar flexingDorsiflexor
Plantar flexorConcentric
Eccentric
![Page 20: Two-segment Model of the Foot for Gait Analysis D. Gordon E. Robertson, Ph.D. Alison Cronin Biomechanics Laboratory, School of Human Kinetics, University.](https://reader036.fdocuments.us/reader036/viewer/2022062306/5a4d1b4f7f8b9ab0599a6f15/html5/thumbnails/20.jpg)
Foot powers(WN01JS)
0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90Time (seconds)
-2000.
-1500.
-1000.
-500.
0.
500.
1000.
1500.
2000.
Pow
er (W
)
Trial: WN01JSFloor powerForce powerMoment powerTotal powerEnergy ratePower imbalance
IFS IHO ITO
![Page 21: Two-segment Model of the Foot for Gait Analysis D. Gordon E. Robertson, Ph.D. Alison Cronin Biomechanics Laboratory, School of Human Kinetics, University.](https://reader036.fdocuments.us/reader036/viewer/2022062306/5a4d1b4f7f8b9ab0599a6f15/html5/thumbnails/21.jpg)
Forefoot powers(WN01JS2)
0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90Time (seconds)
-2000.
-1500.
-1000.
-500.
0.
500.
1000.
1500.
2000.
Pow
er (
W)
Trial: WN01JS2Floor powerMP force powerMP moment powerFf total powerFf energy rateFf power imbalance
IFS IHO ITO
![Page 22: Two-segment Model of the Foot for Gait Analysis D. Gordon E. Robertson, Ph.D. Alison Cronin Biomechanics Laboratory, School of Human Kinetics, University.](https://reader036.fdocuments.us/reader036/viewer/2022062306/5a4d1b4f7f8b9ab0599a6f15/html5/thumbnails/22.jpg)
Rearfoot powers(WN01JS2)
0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90Time (seconds)
-2000.
-1500.
-1000.
-500.
0.
500.
1000.
1500.
2000.
Pow
er (W
)
Trial: WN01JS2MP force powerMP moment powerAnkle force powerAnkle moment powerRf total powerRf energy rateRf power imbalance
IFS IHO ITO
![Page 23: Two-segment Model of the Foot for Gait Analysis D. Gordon E. Robertson, Ph.D. Alison Cronin Biomechanics Laboratory, School of Human Kinetics, University.](https://reader036.fdocuments.us/reader036/viewer/2022062306/5a4d1b4f7f8b9ab0599a6f15/html5/thumbnails/23.jpg)
Conclusions
• adding MP joint reduces error at foot-strike and toe-off
• plantar flexor moment at MP joint does both negative and positive work, but mainly negative
![Page 24: Two-segment Model of the Foot for Gait Analysis D. Gordon E. Robertson, Ph.D. Alison Cronin Biomechanics Laboratory, School of Human Kinetics, University.](https://reader036.fdocuments.us/reader036/viewer/2022062306/5a4d1b4f7f8b9ab0599a6f15/html5/thumbnails/24.jpg)
Questions?
Answers!
Where to go next?
![Page 25: Two-segment Model of the Foot for Gait Analysis D. Gordon E. Robertson, Ph.D. Alison Cronin Biomechanics Laboratory, School of Human Kinetics, University.](https://reader036.fdocuments.us/reader036/viewer/2022062306/5a4d1b4f7f8b9ab0599a6f15/html5/thumbnails/25.jpg)
Thank you