Clinical Gait Analysis

dr. ir. Jaap Harlaar

j.harlaar@vumc.nl
www.vumc.nl/revalidatie

VU University Medical Center

Amsterdam The Netherlands
 Human Movement
Laboratory

Department of
Rehabilitation Medicine
VU University
Medical Center
Amsterdam
casus

3
 Goal setting vs. tools

• problems with specific activities

• >> goal setting at this level
• specific interventions might work
• movement analysis: biomechanics

4
International Classification of Functions
(ICF)
Disease

Function / Activities Participation

Anatomy (Disabilities) (Handicaps)
(Impairments)

External Personal
Factors factors
 Complete nested decision scheme

no treatment General aim of treatment (disability level)

Disability Movement Specific

Decision Decision
assessment analysis treatment

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casus

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Gait and movement analysis in clinical practice of rehabilitation
medicine

GAIT

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 Goal of walking

• To go from one place to another

• Walking speed, Energy & Safety

HOW ?
By repeatedly placing one foot in front of the other

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 Footsteps
Stridelength = Step
Right + StepLeft

Right steplength Left steplength

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 Footsteps (asymmetric)
Stridelength = Right step + Left step

Right steplength Left steplength

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 Measure footsteps

www.gaitrite.com
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 Measure footsteps

www.gaitrite.com
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 Goal of walking

Stridelength [m]

x / 120 = Walking speed [m/s]

Cadence [ steps/min]

3.6 km/h = 1 m/s

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Walking speed=stride length*cadence
2.00

1.80

1.60 1.50 x 60 / 120 = .75

0.25 m/s
1.40
0.50 m/s
Stride length (m)

1.20 0.75 m/s

1.00 m/s
1.00
1.25 m/s
0.80 1.50 m/s
1.75 m/s
0.60
2.00 m/s
0.40

0.20
1.00 x 90 / 120 = .75
0.00
0 20 40 60 80 100 120 140 160

Step rate (steps/min)

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Body length
and stride length

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What is the optimal stridelength ?

1.00

0.90

0.80

Stride length / Body Length

0.25 m/s
0.70
0.50 m/s
0.60 0.75 m/s
1.00 m/s
0.50
1.25 m/s
0.40 1.50 m/s
1.75 m/s
0.30
2.00 m/s
0.20

0.10 StrideLength
=0.008 * StepRate
0.00
BodyHeight
0 20 40 60 80 100 120 140 160

Step rate (steps/min)

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 Energy

Statute

Stridelength

x Walking speed Energy Cost

Cadence

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Energy measurements during gait

• (ambulatory) oxygen
recording
• one ml O2 / min
• = 5 cal / min
• = 20 J/min

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Human gait is very efficient...

optimal:
~3.4 J/kg.m

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How far can you walk on a pastry ?

250 kcal
Energy cost at optimal speed
= 0.8 cal/kg.meter

250.000/(0.8*70)=4,5 km
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Metabolic Energy Measurement

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casus

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 the gaitcycle

One stride lasts from initial

foot contact until the next
ipsilateral initial foot contact

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 the gaitcycle (2)

normalized time: 0 % - 100 %

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Heelstrike & Toe-off

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 the gaitcycle (3)

0 % -- stance -- 60 % -swing-
100%

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 the gaitcycle (4)

RIGHT STANCE RIGHT SWING

LEFT SWING LEFT

STANCE

-- 50 % --

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 the gaitcycle (5)

RIGHT STANCE RIGHT SWING

LEFT SWING LEFT STANCE

RIGHT SINGLE LEFT SINGLE

DO

DO
DO
SUPPORT SUPPORT
UB

UB
UB
LE

LE
LE
SU

SU
SU
PP

PP
PP
O

O
O
RT

RT
RT

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 Functional division of gait phases
(after J. Perry)

Stride (gait cycle)

periods Stance Swing

Weight Single Limb Limb

tasks Acceptance Support Advancement

phases Initial Loading Mid Terminal Pre Mid

Contact Respons Stance Stance Swing Swing
e
Initial Terminal
Swing Swing

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Initial Contact 0%

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Loading Response 0-10 %

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 Functional division of gait phases
(after J. Perry)

Stride (gait cycle)

periods Stance Swing

Weight Single Limb Limb

tasks Acceptance Support Advancement

phases Initial 9 Loading9 Mid Terminal Pre Mid

Contact Respons Stance Stance Swing Swing
e
Initial Terminal
Swing Swing

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Midstance 10 - 30 %

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Terminal Stance 30 - 50 %

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 Functional division of gait phases
(after J. Perry)

Stride (gait cycle)

periods Stance Swing

Weight Single Limb Limb

tasks Acceptance Support Advancement

phases Initial 9 Loading9 Mid 9 Terminal9 Pre Mid

Contact Respons Stance Stance Swing Swing
e
Initial Terminal
Swing Swing

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Pre-Swing 50 - 60 %

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Initial-Swing 60 - 73 %

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 Functional division of gait phases
(after J. Perry)

Stride (gait cycle)

periods Stance Swing

Weight Single Limb Limb

tasks Acceptance Support Advancement

phases Initial 9 Loading9 Mid 9 Terminal9 Pre9 Mid

Contact Respons Stance Stance Swing Swing
e
Initial 9 Terminal
Swing Swing

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Mid-Swing 73 - 87 %

40
Terminal-Swing 87 - 100 %

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 Functional division of gait phases
(after J. Perry)

Stride (gait cycle)

periods Stance Swing

Weight Single Limb Limb

tasks Acceptance Support Advancement

phases Initial 9 Loading9 Mid 9 Terminal9 Pre9 Mid 9

Contact Respons Stance Stance Swing Swing
e
Initial 9 Terminal
Swing Swing 9

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The gait cycle

M.Whittle
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videorapport loopanalyse
datum opname: / /

filenaam STUDY: xxxSYxxx.sty

ˆ rechts
BewegingsLaboratorium
ˆ links

1. initial contact 2. load response 3. midstance 4. terminal stance

5. preswing 6. initial swing 7. midswing 8. terminal swing

Observational
Gait
Analysis form
Rancho Los Amigos
Medical Centre

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Edinburgh GAIT Scoring Table

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Error sources in observational kinematic analysis

• Subjective
• estimation error
• out of plane (2D vs. 3D)

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 Estimation of joint angles

How well do we perform ?

148 º 24 º

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 Estimation of joint angles

How well do we perform ?

148 º 24 º

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Projection error

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Projection error

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 Projectionerror (2)
180

160

140

120
observed angle

100

80

60

40

20

0
0 10 20 30 40 50 60

angle of observation

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Earliest 3D movement analysis
Braun & Fischer 1895

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Multiple 2D projections

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 Calibrate the projection
calibration frame

Direct
Linear
Transformation

15 points are known in the real (3D)

world

Videobased systems: SYBAR, SIMI, PEAK, . . . .

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Automated marker tracking and 3D
reconstruction of marker position

Multiple (2+)
stroboscopic InfraRed
camera's using reflective
markers on the body

Vicon, MotionAnalysis, Elite, Qualysis,. . .

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 Automated marker tracking and 3D
reconstruction of marker position (2)

Active InfraRed markers

3D camera ('s)

CODAmotion, OptoTrak, . . .
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 anatomical clinical
Body model reference convention

marker segment kinematics kinematics

identification anatomical segm. #1
recording marker-cluster 1
joint-
kinematics
kinematics kinematics
marker-cluster n anatomical segm. #2

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 3D Kinematics software

Matlab
www.bodymech.nl

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60
Clinical Feasibility

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Clinical Feasibility

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Clinical Feasibility

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INFORMATION

?
=

KNOWLEDGE

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Observational analysis of pathological movement
Muscle function during movement

Reprinted from: Inman et al.

(1981)

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 Electro Myo Gram (EMG)

EMG is the summation of many

Electrode mounted amplifier
asynchronous Motor Unit Action
Potentials differential lead-off

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Relation EMG and Muscle Force

Raw EMG

Smoothed Rectified
EMG @ 2 Hz

Isometric muscle
force

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the SYBAR system

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the SYBAR system

display

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casus

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Groundreaction force

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Net joint moment

Moment =
Fxr

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Estimated net joint moment
versus inverse dynamics

Moment =
Fxr

Boccardi et al. (1981)

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What therapeutic intervention is needed ?

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 Evaluation of treatment at two (nested) levels

no treatment General aim of treatment (disability level)

Disability function Specific

assessment Decision Decision
analysis treatment

decreased ankle moment at heelstrike

increased walking speed, decreased PCI

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What therapeutic intervention is needed ?

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Complex Clinical Cases

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 Inverse dynamics model
Antropometrics:
•mass
Joint and
•inertal moments
muscle function
•jointlocations
•muscle attachments
- net moments
- estimated
muscle forces

Dynamics Kinematics
external - positions
moments and - angles
forces - derivatives

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 Problem statement

Physical examination yields angles

The measure should address muscle length

The reference values are based on normal gait

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 Method

• Application of a geometrical musculo-skeletal

model SIMM (Delp et.al 1995)
• input 1: joint angles during physical examination
• input 2: joint angles during normal gait
• output: muscle length (origo-insertion)
• all lengths are normalized to anatomical
position(=100 % )

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Results: m. Rectus Femoris (1)

Figure 6.1

•Figure 6.2

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Results: m. Rectus Femoris (2)

120,0%
118,0%
116,0%
114,0%
112,0%
110,0%
108,0%
106,0%
104,0%
102,0%
100,0%
0 12 24 36 48 60 72 84 96 108 120

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Length m. Rectus Femoris during gait

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Results: m. Rectus Femoris (3)

113%
111%
109%
107%
105%
103%
101%
99%
97%
95%
0 8 16 24 32 40 48 56 64 72 80 88 96 % gait

stance swing

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 Discussion

• “Passive” muscle length is not the sole cause

to contractures during gait
• Muscle length during movement and EMG
should be considered
• Warning: validity of the model
• Documentation of examination protocols
(standardisation) using modeling software
animations creates awareness of muscle
length testing

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Imaging •Functional analysis
•Clinical question

•visualization

•Muscle-bone model
•(invers)
•structure •function

•load
•(intended) therapeutical intervention

•musle-bone model
•(forward)
•movement

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casus

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Models (1)

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Models (1)

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functional load and loading capability
of the upper extremity

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Upper extremity

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Upper extremity (2)

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j.harlaar@vumc.nl

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