HUMAN GAIT

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By
Dr C.V.Praneeth Reddy
Final YR PG
ASRAM
ELURU

2. The gait may be defined as the forward propulsion of body
by the lower limbs in a systematic,coordinated semirotatory movements of the trunk,arm and head.
An interplay between loss and recovery of balance with
constant change in the centre of gravity,causing the forward
propulsion of an organism from one place to another.

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Human locomotion is a complex task.
Because of inherent differences in anatomical
structure, motor control patterns, and pathological or
chronological changes, each person's gait pattern is
unique.
However, because everyone has the same basic
anatomic and physiological makeup, human locomotion
occurs in a similar manner for everyone.
The cyclical and highly automated movement pattern
during human locomotion involves rhythmic, alternating
motions of the trunk and extremities.

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There is a clear link between human gait characteristics
and different medical conditions.
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For e.g. high stepping gait in foot drop,
trendelenberg gait in unstable gait.
hand to knee gait in quadriceps weakness.

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Factors required for normal synchronous walking pattern
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Adequate base of support.
Appropriate foot clearance during swing.
Adequate step length.
Conservation of energy.
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It is the time interval or sequence of motions occuring
between two consecutive initial contacts of the same
foot.
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If heel strike is the initial contact,the gait cycle is from
one heel strike to the next heel strike on the same foot.

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Base of support : is the distance between a person’s feet
while standing and during ambulation.
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It provides both support and stability to maintain an erect
posture.
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Normally it should not be more than 2-4 inches from heel
to heel.

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Step length : the linear distance measured along the line
of progression representing how one foot has travelled
during one Gait cycle.
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The average length of a step is approximately 15 inches.

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Stride length : it is the linear distance in the plane of
progression between two consecutive point of foot to
floor contact of the same foot.
Normal : 27-32 inches
Cadence : number of steps taken per minute.
Normal : 90-120 steps for adult.

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Double limb support :
Consists of that portion of the gait cycle when both
feet,the heel of the foot and the toe of the other are
simultaneously in contact with the ground.
During the period of double support,the centre of gravity
is at its lowest point.

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Centre of gravity :
It is an imaginary point at which all the weight of the
body is concentrated at a given instant.
Lies two inches in front of the second sacral vertebra.
Follows an up and down movement as well as the side
to side movement.
Follows a smooth sinusoidal curve and oscillates no
more than 2 inches up and down and from side to side.

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Knee flexion in stance phase
The knee should remain flexed during all components of
stance phase(except heel strike) to prevent the
excessive vertical displacement of the centre of gravity.
For example,in toe off when the ankle with 20 deg. of
plantar flexion,tends to cause the centre of gravity to
rise,the knee flexes to approximately 40 deg. to
counterbalance it.

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Pelvic rotation :
During normal gait,the normal pelvis rotates 8 deg. within
the transverse plane of the body.
This 8 deg. is broken down as 4 deg. forward on the
swing leg and 4 deg. posteriorly on the stance leg.
Pelvic rotation lengthens the femur during the swing
phase through initial foot contact and helps to minimize
the vertical trunk displacement during gait to conserve
energy.

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Pelvic tilt :
The pelvis also rotates within the frontal plane of the
body during gait,which is termed as “pelvic tilt”.
This creates a downward motion of the pelvis of
approximately 5 deg. on the weight bearing limb during
stance.
The “listing” of the pelvis creates adduction of the weight
bearing limb and abduction of the non-weight bearing
limb,thereby improving the efficacy of the hip abductor
mechanism.

15. 
The pelvis and the trunk shift laterally approximately one
inch to the weight bearing side during gait to centre the
weight over the hip.

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Foot and ankle motion :
Ankle is dorsiflexed at heel strike and plantar flexed at
toe off.
The dorsiflexors contract eccentrically from initial heel
contact with the ground,to keep the foot from slapping to
the floor.
The foot acts as a shock absorber by pronating during
the stance phase,during toe-off the foot serves as rigid
lever.

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The trunk,shoulders,arms also rotate to ensure balance
and stability during gait.
The upper limb swings in tandem with the opposite
stance leg in the lower extremity to produce as smooth
balanced gait.

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Two phases
Stance phase – when the foot is off the ground.
Swing phase – when limb is moving forward.

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Begins when the foot contacts the ground and ends
when the foot lift off the ground.
Constitutes 60% of gait cycle.
Most problems become apparent during stance phase
because it bears weight and undergoes greater stress.
Stance phase is divided in to the following components-

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Heel strike/Initial contact :
Begins the instant the heel touches the ground.
At that time the pelvis is rotating forward,the hip is flexed
at 30 deg. and is in neutral rotation and neutral
abduction-adduction.
The knee is almost fully extended and the ankle is in
neutral position.
Active muscles – hip extensors(breaking swing
phase),knee flexors and extensors(stabilize knee),ankle
dorsiflexors(preventing foot slap).

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Foot flat or loading response :
10-15% of gait cycle.
Entire foot contact in ground.
Shock absorbtion primary action in this period.
The lower extremity joints are flexing to minimize
upward excursion of pelvis,which also is beginning to
decrease its forward rotation.
Knee flexes to 15 deg. To aid in the cushioning process
and the ankle plantarflexes to 15 deg. To attain ground
contact.
Active muscles : hip and knee extensors and ankle
plantar flexors.

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Mid-stance :
15-20% of gait cycle.
Body directly over weight bearing leg.
Pelvis has ceased rotating forward while hip and knee in
full extension and the ankle is at neutral with foot in
ground contact.
Active muscles : hip abductors and the ankle plantar
flexors(begin activity of forward propulsion by push
off),posterior tibial and peroneals( stabilize hind foot).

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Heel off/terminal stance :
20-25% of gait cycle.
Heel of the weight bearing limb initially rises from the
floor,weight is unloaded from the weight bearing limb and
transferred to the opposite limb.
Contralateral pelvis rotate forward,hip and knee in
extension and foot neutral or plantarflexed.
Active muscles : hip adductors and the plantar flexors.

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Toe off/ pre-swing :
5-10% of gait cycle.
Knee of weight bearing limb flexes and prepares for the
swing phase.
Contralateral pelvis continues forward rotation.hip
continues in neutral position,knee begins to flex reaching
35 deg.,ankle in full plantarflexion.

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Begins when the foot lifts off the ground and ends when
the foot comes in contact with the ground.
40% of the gait cycle.
Pelvis and limb tends to internally rotate,but the tibia
externally rotates on the femur to improve knee stability
prior to heel strike.
This phase is furthur divided in to :

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Accelaration or initial swing :
5-10% of gait cycle.
Begins the instant,the toes leaves the ground.
The hip flexors accelerate the leg forward to catch up
and eventually get in front of the body.
The hip flexes to 20 deg. in neutral position and the knee
achieves its maximum flexion of 70 deg. while the ankle
moves up to 10 deg. plantarflexion to maintain toe
clearance.

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Active muscles : hip flexors and adductors which are
advancing the limb and ankle dorsiflexors,which are
beginning to bring the foot up.
The knee flexion is caused passively by inertia of leg as
the thigh is advancing rapidly.

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Mid-swing :
20-30% of gait cycle.
In this the non-weight bearing limb passes directly
beneath the body.
The swinging limb advances to achieve a vertical tibial
position with the knee flexed,while hip flexion increases
towards 30 deg.,knee extension occurs passively
reducing the flexion of initial swing from 70 deg. to 30
deg.,and the ankle and foot are brought up to neutral
position.
Active muscles : continued firing of foot dorsiflexors.

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Deceleration/terminal swing :
5-10% of the gait cycle.
The limb decelerates and is in a position of extension
preparing for heel strike.
The pelvis rotates forward,hip flexion reaches 30
deg.,the knee extends to near 0 deg,and the ankle
maintains neutral position.

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Muscle activity picks up as the hip extensors begin to
brake the forward swing and initiate extension.
The knee flexors and extensors begin a synergitic action
and stabilizing activity.
Strong action of the dorsiflexors continue to hold the foot
in neutral position.

32. THANK YOU