Lecture 11
An Introduction to Gait
Gait Parameters/Characteristics
 Temporal – Time parameters
 Spatial – Distance parameters
Kinematics – pertaining to motion
Kinetics – pertaining to the forces regardless of motion.
Traditional Phases of Gait (East-Coast)
Stance Phase (60%)
 Heel-strike (contact) – instant the heel of reference limb
comes in contact with ground
 Foot-flat – initial contact of forefoot with ground
 Mid-stance point– hip/greater trochanter is in vertical
alignment with the vertical bisector of the foot
 Heel-off – instant the heel comes off the ground
 Toe-off – instant the toe leaves the ground
Intervals describing the Stance phase
 Weight Acceptance – HS to FF
 Midstance – FF to HO
 Push-off – HO to TO
Swing Phase (40%)
 Acceleration – rapid acceleration that occurs immediately
after TO
 Midswing – reference limb overtakes the stance limb
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 Deceleration – reference limb decelerates preparing for HS
Ranchos Los Amigos (RLA) – West Coast
Stance Phase (60%)
 Initial Contact (IC)
 Loading Response (LR)
 Midstance (MSt)
 Terminal Stance (TSt)
 Preswing (PSw)
Swing Phase (40%)
 Initial Swing (Isw)
 Midswing (MSw)
 Terminal Swing (TSw)
Traditional
RLA
% of GC
HA
IC
0-2
Stance Phase (60%)
FF
MSt
HO
LR
MSt
TSt
0-10 10-30 30-50
TO
PSw
50-60
Swing Phase (40%)
AC
MSw
DC
Isw
MSw TSw
60-73 73-85 85-100
Spatial Parameters
1. Stride length – distance from point of IC of reference limb to the
point of the next IC of same limb
 4.2 ft. women / 4.8 ft. men / 4.6 ft. overall
2. Step length – distance from point of IC of reference limb to the
point of IC of contralateral limb
 2.1 ft. women / 2.4 ft. men / 2.3 ft. overall
3. Base of Support – perpendicular distance with reference to the
progression line between posterior aspect of the heel of the
reference limb and the posterior aspect of contralateral heel
 2-4 inches
4. Angle of Toe Out – angle between line of progression and
logitudinal axis of foot (normal 7 degrees).
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Temporal Parameters
1. Cadence – number of steps/time (113 steps/minute)
2. Walking velocity – speed of ambulation on smooth, level surface
 250 ft./min. women / 276 ft./min. men / 262 ft./min. overall
3. Stride duration – time to complete a single stride
5. Step duration – time to complete a step
6. Stance time – duration of stance phase
7. Double support time – duration of time when both limbs are in
contact with ground (20% of GC)
8. Single support time – duration of time when a single limb is in
contact with the ground (80% of GC)
Range of Motion Table (14-1)
Total ROM
Hip
Knee
Ankle
Stance
0-30  * 0 – 20 /
0 – 40 deg 
0 – 10 dflex * 0 – 20 pflex
Swing
20-30 deg 
0- 60 deg 
0 – 10 pflexion
Other Gait Concepts / Terminology
HAT / Passenger Unit – includes the head, arms, trunk, and pelvic girdle
What causes the movements associated with gait?
Forces  Kinetics
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1.
2.
3.
4.
gravity
muscular contraction
inertia
ground reaction forces (Newton’s 3rd law)
Ground Reaction Force Vector (GRFV) – Body Force Vector
 As body weight (COG) falls toward the floor, it creates a force in
the floor of equal magnitude but opposite in direction
 Relate the body vector to the joint centers to determine the
magnitude and direction of the instability (moments)
 Imaginary line connecting COG and COP
Figure 3.7 in Perry
Walking is a series of controlled falls.
Body Subdivisions
 Passenger Unit (HAT) – head, neck, trunk, and arms
 Carried rather than directly contributing to walking
 Locomotor Unit – lower extremities and pelvis
 11 jts – lumbosacral(2), hip, knee, ankle, subtalar, MTPs
Locomotor Functions
1. propulsion
2. stance stability – upright stability is maintained despite everchanging posture
3. shock absorption
4. energy conservation
Basic objective of Locomotor Unit is to move the passenger unit forward
along the line of progression.
Body uses gravity as a propulsive force.
Controlled falling from one stance limb to the other.
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