Adelaide Health Service
Falls Prevention Network
Gait Speed and Falls
Gill Bartley Program Manager Falls Prevention
Central and Northern Adelaide Health Areas
Outline
Introduction
Measurement
Interpretation
Predictive Value
Modulation
Community Ambulation
Case Examples
Summary
Introduction
Why all the fuss about gait?
50% of the falls occur during some form of locomotion.
It is during walking that we challenge our system the most:
initiating and terminating gait, turning, avoiding obstacles
(altering step length, changing direction, stepping over
objects), bumping into people and objects.
•Trips
•Slips
•Gait Speed
•Perturbations
Gait and Falls
“During normal locomotion, the COM falls
outside the boundaries of the BOS for 80%
of the stride, which represents an unstable
condition”. Grabiner 1993
“The maintenance of balance during walking
represents a considerable challenge to the
postural control system”.
(Lord, Sherrington and Menz - Falls in Older People)
Measurement
Measurement of gait speed
Divided into:
• Distance (6, 10 or 20m)
• Pace (comfortable vs fast vs slow)
Stratified by:
• Gender
• Age
Other variables:
Assistive device
Number of steps
Assessor
Line crossing
Measurement
Gait speed =
distance
time
Valid, reliable, sensitive and easily administered
Which group would have the greatest speed consistency?
•Amputee
•Stroke
•Healthy seniors
Measurement
Q: Is there an optimal distance for gait speed measurement?
The community guidelines only mention the 6 metre
test
2008 Study looked at gait speeds across 8 and 20 feet
and found a strong correlation.
Q: Which distance should be used at either end of the gait track?
Between 1 step and 3 metres – whatever space permits
Another guide indicates 5 feet (a little over 1.5 metres) before
and after the markers
The community guidelines specify 2 metres
Q: Why the start and finish lines?
To eliminate acceleration and deceleration phases and
ensure constant speed is measured
Don’t forget to observe gait
pattern too!
Stride to stride variability
temporal
spatial
Base of support (width)
Arm swing
Fast versus comfortable gait speed –
which measure tells us more?
> Comfortable gait speed best known
> Max gait speed can show more variability,
especially when there are cognitive
issues (comfortable gait speed is more
automated, requiring limited cognitive
resources)
> Minimum gait speed may be most
sensitive to balance impairment
How well does gait speed align
with:
1. TUG
TKR,
THR,
# NOF
2. 6 minute walk test
TUAG segments
•Sit to stand
•chair to 3 metre mark
•turn
•3 metre mark to chair
•stand to sit
Interpreting Gait Speed
Women walk faster than men
Age
Group
Comfortable gait speed
(m/sec)
Maximum gait speed
(m/sec)
20’s
Male
1.39
2.53
Female
1.41*
2.47
Male
1.46
2.46
Female
1.42
2.34
Male
1.46
2.46
Female
1.39
2.12
Male
1.39
2.07
Female
1.39
2.01
Male
1.36
1.94
Female
1.30
1.77
Male
1.33
2.08
Female
1.27
1.75
Male
0.88
1.29
Female
0.80
1.20
Male
0.72
1.27
Female
0.71
1.05
30’s
40’s
50’s
60’s
70’s
80’s
90’s
Do gait aids slow walking down?
Age
Group
Mean comfortable
gait speed (m/sec)
Mean maximum
gait speed (m/sec)
60-69
Male
1.26
1.96
Female
1.24
1.81
Overall
1.24
1.84
Male
1.25
1.94
Female
1.25
1.80
Overall
1.25
1.86
Male
0.88
1.29
Female
0.80
1.20
No device
0.91
1.38
Device
0.82
0.88
Male
0.72
1.27
Female
0.71
1.05
No device
0.88
1.29
Device
0.59
0.93
70-79
80-89
90-101
Tall people walk more economically
Walkers have been
found to use the
same amount of
energy per stride,
despite their height.
However tall people
walk more
economically
because they need
to take fewer steps
to cover the same
distance.
Interpreting Gait Speed
Slow
Moderate
Fast
The ability to adjust the speed of progression is an important mechanism
that adapts locomotor activity to changes in environmental demands.
For functional ambulation (especially community ambulation), we need
to adjust gait speed.
Gait parameters at increased speeds
COM displacement:
Med / lat
Ant / post
Cadence
Step length
Step width
Gait parameters at different
speeds
0.6 m/sec or less
Seriously abnormal
0.6 - 1.0 m/sec
Abnormal
1.0 – 1.4 m/sec
Normal
(similar to the recommended cut-off in
the 6 minute walk test of 350m)
1.4 m/sec
Superior
International Academy of Nutrition & Aging
http://www.healthandage.com/html/min/iananda/task_force.htm
What is the term used to
describe slowed gait?
Why is gait slowed?
Some factors may include:
decreased motor units
Substitution of type I with type II muscle fibres
Reduced cutaneous sensitivity
Decreased nerve conduction velocity
Decreased reaction times
Decreased grey matter volume
Presence of white matter lesions
Specific aspects of cognition specifically associated with (max)
walking speed
Verbal fluency (Isaacs set test – lists words in 4
semantic categories)
Psychomotor speed (trail making test – amount of time
taken to connect numbers – pencil and paper task)
Global tests less strongly associated
Interpreting Gait Speed
Slowed gait is not independently
associated with falling
<.57m/s associated with falls
Increased lateral
loading seen in feet
Slow
Stabilising adaptations:
•Decreased stride length
•increased double support
time
•Wider BOS
Moderate
Greater demand:
•swing phase more active
•Loss of stabilising influence of arm swing
•Larger horizontal excursions of BOS –
greater muscle efforts required
•Increased vestibulospinal drive
BUT gait variability is independently associated with falls
• Stride length
• speed
• double support time
Fast
Slowed gait – added demands!
Bradypedia – added demands!
> Altered pattern of foot loading
> At <.28 m/s, there is an increase in
muscle activity
> There is increased vestibulospinal drive
which is destabilising
> Increased dynamic instability – postural
muscle synergies are called more into
play (less locomotor synergies)
> Greater horizontal excursions of the
centre of mass
Interpreting Gait Speed
Least energy utilised
•Swing essentially ballistic
Slow
Moderate
Fast
Interpreting Gait Speed
•
•
•
•
•
Slow
Reduced double support time
Decreased stance phase**
Increased cadence (usually)
Increased stride length (usually)
Swing phase is shortened less readily than stance
phase but greater acceleration / deceleration can
serve to reduce swing time
Moderate
•
Fast
Amplitude of muscle activity increases
Fast Gait Speed
Cadence
↑
Stride length
↑
↓**
↑
↓
~
↑
↓
Stance
Knee flexion in stance
Double stance
Swing phase
Energy use
Centre of gravity excursion
Interpreting Gait Speed
When does walking
become running?
Slow
Moderate
Fast
When there is no
double support time
Predictive Value
Predictive value
Predicts a wide array of outcomes, including:
•Survival
•Disability (<0.6 m/sec)
•Hospitalisation / institutionalisation
•Dementia
•Falls
•High risk of major health –related events = <1.0 m/s
• Cardiac surgery: able to identify patients at risk of
mortality and major mortality after cardiac surgery
•As reliable as larger batteries such as the SPPB (Short
Physical Performance Battery) in predicting adverse
outcomes.
Predictive value
Gait speed of < 1 m/sec (or 0.8 m/sec*) identifies
persons at high risk of health-related outcomes
including mortality and physical disability in well
functioning older people
(Cesari et al 2005, Montero-Odasso et al 2005)
Improvements in gait speed predict a substantial
reduction in mortality.
(Hardy et al 2007)
Gait Speed of <0.6 m/sec is predictive of future risk
of hospitalisation and decline in health and
function.
(Studenski S)
Predictive value
Only fast gait speed was been shown to be an
independent predictor of cognitive decline (MMSE
score) over 3 years. Better than “walking while
talking” Why?
Recurrent falls have been associated with slower
walking speed while counting backward.
Predictive value
< 1.8 feet/sec (0.55 m/sec)= risk for recurrent falls
sensitivity 72%
specificity 74% (Van Swearington JM 1998)
<1.9 feet/sec (0.58 m/sec) = would benefit form PT
assessment and possible treatment
sensitivity 80%
specificity 89% (Harada N 1995)
Gait Speed and Energy Expenditure
Reflects the functional capacity for ADL’s
Gait Speed Energy
Likely ADL
Requirement capacity
.67 m/sec
or less
2 METS
Likely to have limited
energy for self care
1.1 m/sec
or more
3 METS
Likely to have
sufficient energy
capacity to perform
household activities,
light yard work or
carrying groceries
Normal gait - low muscular demand
~ 20-25% max. muscle strength
Capacity to Modulate Speed
Capacity to reduce gait speed
A study looking into frictional requirements of amputees at
numerous gait speeds found “Some volunteers were not
able to walk at a velocity slower than their normal one”
A report published in 1991 compared selected gait speeds
for women who were sedentary, community active and who
exercised.
Pace
(m/sec)
Very
Slow
Slow
Normal Fast Very
Fast
Sedentary
0.47
0.71
0.99
1.17
1.39
Community 0.47
Active
Group
0.74
0.99
1.17
1.41
0.34
0.65
0.94
1.15
1.49
Exercising
Group
Capacity to increase gait speed
An individual who cannot increase walking speed when
asked to do so may not benefit from gait training focusing
on increasing gait speed but instead may benefit from
further evaluation and intervention targeted toward
recognised deficits in physical performance…”
Brach 2001
Community Ambulation
Gait speed for community
ambulation
Recommended community ambulation speed is:
.79 m/s in urban areas
.74 m/s in rural areas
1.22 m /sec
Pedestrian Safety
Pedestrians aged 60 years and older accounted for
40% of all pedestrian fatalities in 1995 even though
they made up only 15% of the population.
The elderly have the highest rate of pedestrian
death and injury when adjustment is made for
exposure
Characteristics of those experiencing
difficulties crossing roads
Of those who reported difficulty crossing roads;
• 81% reported insufficient time to cross
• 78% said they needed help to cross
In a study of New Haven elders (n=1249)
1. Those needing help with one or more ADL’s 10
times more likely to report difficulty crossing the
street
2. Those with slowest walking speeds 3 times more
likely to report difficulty crossing the street
3. Strongest independent factor associated with
reported difficulty crossing roads: need for help or
special equipment for at least one ADL.
Problems Facing the Aged
(Monash University 1995)
>took twice as long to assess the traffic and
cross the road than younger adults.
>spent more time looking at the ground on the
approach to and while crossing the
roadway and less time studying the traffic
in near- and far-side lanes.
>more likely to be confused crossing the road in
complex traffic situations where
decisions involve the integration of
multiple sources of sensory information.
>slow to react to approaching traffic.
Problems Facing the Aged
Often failed to compensate adequately for their
reduced abilities.
Langlois’ Newhaven study in 1997 found that 99% of
elders aged 72 years or older had a gait speed of less
than 1.22m/sec.
But only 141 / 1249 reported difficulty crossing roads
In one study, elders were instructed to cross an
intersection at their fastest speed. Despite this,
60% (70 years or older) could not achieve
sufficient walking speed (1.22.m/s)
Langlois 1997
Problems Facing the Aged
>failed to check and re-check traffic once they
commenced their crossing and more commonly
forced to interact with traffic around them.
>In less complex road settings, pedestrian
behaviour was more safe and more like that of
younger pedestrians.
Strategies
>Increase crossing times (allowing for gait
speed of .09 m/s) – especially in areas where
large numbers of elderly people live
>Provide refuge zones / traffic islands
>Reduced traffic speeds
Escalators
Imposed
speed
with
sensory
conflict
Case Examples
Group Activity - calculating your
gait speed!
Case Example 1
Len attends your service for assessment.
He is 79 years old and uses a four wheeled walker.
As part of your routine testing, his self selected gait
speed is measured over 6 metres. He records a
time of 8 seconds.
What is Len’s gait speed?
Is his walking speed sufficient for
road crossing?
What is the normative data for his
age?
What is it expected to be with an
assistive device?
What metabolic equivalent of task
(MET) does he need to walk at this
speed?
Is the indicative MET sufficient to
carry out all household tasks?
What is Len’s gait speed?
6 / 8 = 0.75 m/sec
Is his walking speed
Probably not
sufficient for road crossing?
What is the normative data
for his age?
1.25 m/s
What is it expected to be
with an assistive device?
0.82
What metabolic equivalent Between 2 and 3 MET
of task (MET) does he need
to walk at this speed?
Is the indicative MET
sufficient to carry out all
household tasks?
Energy levels probably
not sufficient– some
modifications or
assistance likely
Case Example 2
Sheila attends your service for assessment.
She is 83 years old and walks unaided.
As part of routine testing, her self selected gait speed
is measured over 10 metres. She records a time
of 13 seconds.
Her maximum gait speed is
virtually the same, recording
a time of 13.5 seconds. You
notice that she is unable to
stride out.
What is Sheila’s gait speed?
Is her walking speed sufficient for road
crossing?
What is the normative data for her age?
What metabolic equivalent of task (MET)
does she need to walk at this speed?
Is the indicative MET sufficient to carry out
all household tasks?
Is she likely to benefit from gait speed
training?
What clinical impressions can you draw
from her difficulty in increasing her gait
speed?
What is Sheila’s gait speed?
0.77 m/s
Is her walking speed sufficient no
for road crossing?
What is the normative data for 0.8 m/s (self selected)
her age?
1.2 m/s (maximum)
What metabolic equivalent of
task (MET) does she need to
walk at her gait speed?
Between 2 and 3 MET
Is the indicative MET
sufficient to carry out all
household tasks?
Unlikely
Is she likely to benefit from
gait speed training?
Probably not
What clinical impressions can
you draw from her difficulty in
increasing her gait speed?
May not benefit from gait training
focussing on speed but further
evaluation and intervention targeting
recognised deficits in physical
performance
Summary
Gait Speed –
is it the Sixth Vital Sign?
Ability to
> Predict future health status
> Ease of administration
> Ease of grading
> Ease of interpretation
> Strong test-retest reliability for both fast
and usual gait speed testing
> Minimal cost
Should it part of routine care?
Key Messages
“Gait speed may be considered a new “vital
sign” specifically sensitive for older persons”
(Cesari 2011)
Gait speed may serve as a marker of
physiological reserve and potentially could
quantify overall heath status (Cesari 2011)
Gait speed presents a global marker of
health status. It “has the potential to serve
as a core indicator of health and function in
aging and disease” (Studenski 2009)
Key Messages
The control of gait is a strong predictor of
falls
Used to assess change over time to assess
effectiveness of treatment or rehabilitation
program. May also alert to a worsening
medical condition.