Biomechanics Gait cycle Gait

1. Gait

2. • Rhythmic ,cyclic movement of the limbs in
relation to the trunk resulting in forward
propulsion of the body.

3. Phases of gait cycle:
• A stance phase ,
• A swing phase.
Events in stance phase:
• Initial contact or heel strike.
• Foot flat
• Midstance
• Heel-off
• Toe-off.

4. Swing phase:
• Acceleration phase
• Midswing
• Deceleration phase

5. Gait terminology :
• Base of support (BOS)
• Step length
• Step width
• Stride length
• Gait cycle
• Cadence – approx.70 steps per min.
• Walking velocity
• Double limb support
• Single limb support
• Ground reaction force vector.

6. • Normal walking requirements :
Equilibrium
the ability to assume an upright posture and
maintain balance.
Locomotion
the ability to initiate and maintain rhythmic stepping
Musculoskeletal Integrity
normal bone, joint, and muscle function
Neurological Control,
must receive and send messages telling the body
how and when to move. (visual, vestibular, auditory,
sensorimotor input)

7. Stride length – The linear distance between two
successive events that are accomplished
• By the same lower extremity during gait.
Step length – Linear distance between two successive
point of contact of opposite extremity.
Step width – Linear distance between the Mid point of
heel of one foot and the Same point of other foot.
Degree of toe-out- this angle is formed by the each foot
line of progression and the line intersecting the center
heel and second toe . Normal 7 degree.

9. • Cadence : number of steps taken by a person
per unit of time.
Normal 80-120 steps per minute.
• Increased in cadence = decreased in the
duration of the double –support period.
• Walking approached 180 steps per minute ,
the period of double support disappears ,and
running occurs

10. Double support limb: during normal gait , two
lower extremities are in simultaneous contact
with the ground.
• During this period, both legs support the body
weight.
• It happens between push off and toe off on
same side and heel strike and foot flat on the
contralateral side.

11. • Gait Analysis – Forces
Forces which have the most significant
Influence are due to:
(1) gravity
(2) muscular contraction
(3) inertia
(4) floor reaction

12. Gait deviation : gait deviation is an abnormality in the gait
cycle that affect the trunk, hip, knee or ankle joint.
• CAUSES OF GAIT DEVIATIONS
• Pain or discomfort during weight-bearing or movement
• Muscle Weakness
• Limitations of joint movement
• In-coordination of Movement
• Changes in bone or soft tissue (including amputations)
• Pain or Discomfort:
• Report of pain and location
• May spend less time in weight-bearing phase
• Grimacing

13. Antalgic gait
• Antalgic gait refers to the posture or style of
walking in order to avoid or reduce the pain
on a weight-bearing structure, such as the
ankle, hip or knee.
• As a result, a limp usually occurs when pain is
experienced, due to the shortened phase of
the gait when on the injured side.

14. • These gait usually relates to a disorder of the
lower back or lower extremity.
• Causes – minor injuries, arthritis or vascular
disease.

15. • Gait pattern in which stance phase on
affected side is shortened
• Corresponding increase in stance on
unaffected side
• Common causes: OA, tendinitis

16. Arthrogenic (Stiff hip or Knee) Gait:
•This gait results from stiffness, laxity or
deformity and it may be painful or pain free.
•Patient with this gait lifts entire leg higher than
the normal to clear the ground because of stiff
hip or knee.

17. • Causes – joint lesion such as OA, avascular
necrosis of the femoral head , RA.

18. Trendelenburg gait or Gluteus Medius:
The Trendelenburg gait is an abnormal gait
caused by weakness of the abductor muscles of
the lower limb, gluteus medius and gluteus
minimus.
• During the stance phase, the weakened
abductor muscles allow the pelvis to tilt down
on the opposite side.

19. • It is caused by unilateral weakness in the hip
abductors.
• During normal gait , each lower limb bears half of
the body weight
• In stance phase- the pelvis normally tilts
downwards on the weight bearing extremity and
hikes up on the non-weight bearing extremity.
• But in case of abductor weakness, the pelvis tilts
downwards on the non-weight bearing extremity
instead of upwards.
• To compensate it , the individual engages in a
lateral tilt of the trunk away from the affected
hip.

20. • It is observed in the patient with
developmental dysplasia of the hip, congenital
dislocation of the hip(CHD), congenital coxa
vara ,or coxa valga etc.
• These gait is characterised by – trunk shift
over the affected hip during the stance phase
and away during the swing phase of gait.

22. Scissors Gait/ diplegic crouch gait:
 Cross over of adductors; bilateral
Result of spastic paralysis of the hip adductor
muscles
Causes knees to be drawn together so that the legs
can be swung forward only with great effort
Seen in spastic paraplegics and cerebral palsy
patient
•

23. • It is characterized by hypertonia and flexion in
the legs , hips and pelvis accompanied by
extreme adduction leading to the knees and
thighs hitting, or even crossed- scissors like
movement.
• Causes- high muscle tone(spasticity)in the hip
adductors.
• Upper motor neuron
• Common in spastic diplegia

24. Plantar Flexor Gait
• If the plantar flexor muscles are unable to
perform their function, ankle and knee
stability are greatly affected.
• The stance phase is less and there is shorter
step length on the unaffected side.

25. FOOT DROP OR STEPPAGE GAIT:
• Weak or paralyzed dorsiflexor muscles
resulting in drop foot
• Patient lifts the knee higher than normal
to compensate and avoid dragging the
toes

26. • Ankle and foot dorsiflexors(tibialis anterior,
extensor digitorum longus, and extensor
hallucis longus) help clear the foot during the
swing phase of walking and control plantar
flexion of the foot on heel strike.
• Weakness in the ankle and foot dorsiflexors
results in an equino varus deformity.
• Causes- damage to the common peroneal
nerve , there will be weakness of tibialis
anterior and dorsiflexors of the foot.

27. Quadriceps gait /Gait associated with femoral neuropathy:
•If the quadriceps muscle have been injured (eg:
femoral nerve neuropathy, reflex inhibition, trauma.),the
patient compensates in the trunk and lower leg.
•forward flexion of the trunk combined with strong ankle
plantar flexion causes the knee to extend (hyperextended)
•If the trunk, hip flexors and ankle cannot perform this
movement, patient may use the hand to extend the knee.

28. • Causes- disuse atrophy secondary to pain in
the involved joint, certain neurological
condition like stroke or nerve damage.
• The quadriceps provides instability during
stance phase in the gait cycle.

29. • Quadriceps action is needed during heel strike
and foot flat when there is a flexion
movement acting at the knee
• Quadriceps weakness or paralysis will lead to
buckling of the knee during gait and loss of
balance
• In quadriceps weakness, forces tend to flex
the knee- the compensatory mechanism is
patient lean forward to bring the body weight
anterior to the knee resulting in a straight
knee with excessive plantar flexion and a
forward trunk.

31. Excessive knee extension/ genu recurvatum
gait:
•Loss of normal knee flexion during stance
phase
•Knee may go into hyperextension
•Genu recurvatum: hyperextension deformity of
knee
•Common causes:
Quadriceps weakness (mid-stance)
Quadriceps spasticity (mid-stance)
Knee flexor weakness (end-stance)

32. • Knee extension spasticity is commonly
considered the primary cause of post-stroke
stiff knee gait., pain , muscle weakness

33. Gluteus Maximus Gait/ lurching gait :
• Weak gluteus maximus (primary hip extensor) results in
patient thrusting the thorax posteriorly at heel strike to
maintain hip extension of the stance leg
• They have to lean back for heel off & push off to get posterior
concavity because gluteus isn’t engaging in extension
Characteristic backward lurch of trunk; thoracic posterior
lurch

34. • In paralysis of gluteus maximus , patient
lurches backward during stance phase
• Causes- paralysis or weakness of the gluteus
area.it causes a slow and long stride , our
body can jerk backward to lessen the weight
on the affected leg.

35. SHORT LEG GAIT:
• One leg is shorter or there is a deformity
• Lateral shift to the affected side and the pelvis tilts
down on the affected side creating a limp
• May supinate the foot on the affected side to try to
lengthen the limb
• Weight bearing phase may be same for both legs

36. Ataxic Gait:
• Poor sensation or lack of muscle coordination results in
poor balance and a broad base
• Gait is irregular, jerky and weaving
• Feet slap the ground because they cannot be felt
• Patient watches the feet while walking

37. • Difficulty in walking in a straight line, lateral
veering, poor balance, a widened BOS,
inconsistent arm motion, lack of repeatability.
• Shortened stride length, high step pattern and
decreased push-off and veering.

38. HEMIPLEGIC GAIT:
•Due to cerebral infarct/stroke (lack of blood to brain)
•Leads to spastic paralysis (paralyzed but
tight/contracted) on one side of body
•Affected upper limb is carried across the trunk for
balance
•Patient swings paraplegic leg outward and ahead in a
circle or pushes it ahead

39. • What seen – reduced stride length, reduced
knee flexion, ankle plantar flexion and
inversion and circumduction to allow
clearance of the affected leg.
• Characteristics- decreased cadence, prolonged
swing duration on the paretic side, prolonged
stance duration on the nonparetic side, and
step length asymmetry.

40. • Causes- vascular(stroke, diabetic
neuropathy),infective, traumatic brain injuries
etc

41. Parkinson’s Gait:
• Result of Parkinson’s disease
• Patient’s neck, trunk, and knees are flexed
• Characterized by shuffling or short rapid steps
• Arms are held stiffly and do not have their
normal associative movement
• Patient may lean forward and walk
progressively faster as though unable to stop.

43. Spastic gait:
• Presentation: Asymmetric foot dragging.
• Conditions associated with a spastic gait
– Brain tumor
– Brain abscess
– Cerebral palsy
– Cerebrovascular accident
– Multiple sclerosis

44. • Spastic gait- a stiff, foot-dragging walk caused
by a long muscle contraction on one side.,
• Muscle are too tight and hypertonic with a
limited range of motion.

45. Myopathic gait (or waddling gait):
• The "waddling" is due to the weakness of the proximal
muscles of the pelvic girdle.
• The patient uses circumduction to compensate for gluteal
weakness.
Conditions associated with a myopathic gait
• Pregnancy
• Congenital hip dysplasia
• Muscular dystrophy
• Spinal muscle atrophy

46. • Causes- congenital hip dysplasia, muscular
dystrophy, muscle disease.