gait biomechanics

1. GAITGAIT
BY
Dr. AMRIT KAUR (PT)
Lecturer, N.D.M.V.P college of physiotherapy
nashik

2. GAITGAIT
 Normal GaitNormal Gait
Series of rhythmical , alternating movements ofSeries of rhythmical , alternating movements of
the trunk & limbs which result in the forwardthe trunk & limbs which result in the forward
progression of the center of gravityprogression of the center of gravity
 One gait cycleOne gait cycle
period of time from one heel strike to the nextperiod of time from one heel strike to the next
heel strike of the same limbheel strike of the same limb

3. GAIT CYCLEGAIT CYCLE
► The gait cycle consist of 2 phases for each footThe gait cycle consist of 2 phases for each foot
Stance (60 percent of the cycle )
 Begins when the heel of one leg strikes the ground and
ends when the toe of the same leg lifts off.
Swing (40 percent)
 Swing phase represents the period between a toe off on
one foot ad heel contact on the same foot.

5. ► Time FrameTime Frame::
A. Stance vs. Swing:A. Stance vs. Swing:
►Stance phaseStance phase == 60% of gait cycle60% of gait cycle
►Swing phaseSwing phase == 40%40%
B. Single vs. Double support:B. Single vs. Double support:
►Single support=Single support= 40% of gait cycle40% of gait cycle
►Double support=Double support= 20%20%

7. Gait Cycle - SubdivisionsGait Cycle - Subdivisions
► A.A. Stance phase:Stance phase:
1.1. Heel contact: ‘Initial contact’.Heel contact: ‘Initial contact’.
2.2. Foot-flat: ‘Loading response’, initial contact ofFoot-flat: ‘Loading response’, initial contact of
forefoot on ground.forefoot on ground.
3.3. Midstance: greater trochanter in alignment w.Midstance: greater trochanter in alignment w.
vertical bisector of footvertical bisector of foot
4.4. Heel-off: ‘Terminal stance’Heel-off: ‘Terminal stance’
5.5. Toe-off: ‘Pre-swing’Toe-off: ‘Pre-swing’

10. Gait Cycle - SubdivisionsGait Cycle - Subdivisions
► B.B. Swing phase:Swing phase:
1.1. AccelerationAcceleration: ‘Initial swing’: ‘Initial swing’
2.2. MidswingMidswing: swinging limb overtakes the limb in: swinging limb overtakes the limb in
stancestance
3.3. DecelerationDeceleration: ‘Terminal swing’: ‘Terminal swing’

11. DISTANCE AND TIME
VARIABLES
► Temporal
variables
1. Stance time
2. Single limb support
time
3. Double limb support
time
4. Swing time
5. Stride and step time
6. Cadence
7. speed
► Distance
variables
1. Stride length
2. Step length
3. Width of walking

12. ► Step length
Distance between corresponding successive points ofDistance between corresponding successive points of
heel contact of the opposite feetheel contact of the opposite feet
► Stride length
Stride length is determined by measuring the linear
distance from point of heel strike of one lower
extremity to next heel strike of same extremity.
► Width of base of support
Side-to-side distance between the line of the two feetSide-to-side distance between the line of the two feet
► Degree of toe outDegree of toe out
It is the angle formed by each foot’s line of progression
and a line intersecting the centre of the heel and
second toe.

14. KINEMATICS AND KINETICS OF GAIT
►Path of Center ofPath of Center of
GravityGravity
 midway between themidway between the
hipships
 Few cm in front of S2Few cm in front of S2
 Least energyLeast energy
consumption if CGconsumption if CG
travels in straight linetravels in straight line

15. Path of Center of GravityPath of Center of Gravity

16. Path of Center of GravityPath of Center of Gravity

17. HEEL STRIKE TO FOOT FLAT
► Heel strike to forefoot loading
► Foot pronates at subtalar joint
► Only time (stance phase) normal
pronation occurs
► This absorbs shock & adapts foot
to uneven surfaces
► Ground reaction forces peak
► Leg is internally rotating
► Ends with metatarsal heads
contacting ground

20. Sagittal plane analysis
Joint Motion GRF Mome-
nt
Muscle Contraction
Hip Flexion
30-25
Anterior flexion G.Maximus
Hamstring
Add.magnus,
Isometric
to ecentric
knee Flexion
0-15
Anterior
To
Posterior
Extensi-
on to
flexion
quadriceps Concentric
to ecentric
ankle Plantar-
Flexion
0-15
Posterior PF Tibialis anterior
Ex. digitorum
longus
Ex.hallucis
longus
ecentric

21. Frontal plane analysis
JOINT MOTION
Pelvis Forwardly rotated position
Hip Medial rotation of femur on pelvis
knee Valgus thrust with increasing valgus
Medial rotation of tibia
Ankle Increase pronation
Thorax posterior position at leading ipsilateral side
Shoulder Shoulder is slightly behind the hip at ipsilateral
extremity side

22. FOOT FLAT TO MIDSTANCE

23. FOOT FLAT TO MIDSTANCE
(SAGITTAL PLANE)
Joint Motion GRF Moment Muscle Contractio
n
Hip Extension
25-0
Flexion-0
Anterior to
posterior
Flexion
to
extensi-
on
G.maximus Concentric
to no
activity
Knee Extension
15-5
15-5
flexion
Posterior to
anterior
Flexion
to
extensi-
on
Quadriceps Concentric
to no
activity
Ankle 15 of PF to
5-10 of DF
Posterior to
anterior
PF to
DF
Soleus,
gastronem-
ius, PF
Eccentric

24. Frontal plane analysis
Joint Motion
Pelvis Ipsilateral side rotating backward to reach
neutral at midstance ,lateral tilting towards the
swinging extremity.
Hip Medial rotation of femur on the pelvis continue
to neutral position at midstance. adduction
moment continue throughout single support.
Knee There is reduction in valgus thrust and the tibia
begins to rotate laterally.
Ankle The foot begins to move in the direction of
supination from its pronated position at the end
of loading response. The foot reaches a neutral
position at midstance.

25. Frontal plane analysis
Ankle The foot begins to move in the direction of
supination from its pronated position at
the end of loading response. The foot
reaches a neutral position at midstance.
Thorax Ipsilateral side moving forward to neutral.
shoulder Moving forward

26. MIDSTANCE TO HEEL OFF

27. MIDSTANCE TO HEEL OFF
(sagittal plane analysis)
Joint Motion GRF Moment Muscl
e
Contract-
ion
Hip Extension 0
to
hyperexten
sion of 10-
20
Posterior Extension Hip
flexors
Eccentric
Knee Extension 5
degree of
flexion to 0
degree
Posterior
to
anterior
Flexion to
extension
No
activity

28. Ankle PF:5 degree
of DF to 0
degree.
Anterior DF Soleus
PF
Eccentric
to
concentric.
Toes Extension:
o-30 degree
of
hyperextens
-ion.
Flexor
hallicus
longus and
brevis
Abductor
digiti quinti,
interossei,
lumbricals

29. MIDSTANCE TO HEEL OFF
(frontal plane analysis)
Joint Motion
Pelvis Pelvis moving posteriorly form neutral position
Hip Lateral rotation of femur and adduction
Knee Lateral rotation of tibia
Ankle –
foot
Supination of subtalar joint increases
Thorax Ipsilateral side moving forward
Shoulder Ipsilateral shoulder moving forward.

30. HEEL OFF TO TOE OFF

31. HEEL OFF TO TOE OFF
(sagittal plane analysis)
Joint Motion GRF Moment Muscle Contraction
Hip Flexion :20
degree of
hyperextensi-
on to 0
degree.
Posterior Extension
to neutral
iliopsoas
Adductor
magnus
Adductor
longues
concentric
Knee Flexion :o-
30degree of
flexion
Posterior Flexion Quadrice
ps
Ecentric to
no activity

32. Ankle PF :0-20
degree of PF
Anterior DF Gastronemius.
soleus, peroneus
brevis, peronius
longus.
Concentri
c to no
activity
Toes
(MTP)
Extension: 50-
60 of
hyperextension.
Flexor hallucis
longus
Adductor hallicus
Abductor digiti
minimi
Flexion digitorum
brevis and hallicus
brevis, inrossei,
lumbricals
Close
chain
resonse
to
increasing
PF at the
ankle.

33. HEEL OFF TO TOE OFF
(frontal plane analysis)
Joint Motion
pelvis Contralateral side moving forward unless
contralateral heel touches the ground.
Hip Abduction occur, lateral rotation of femur
Knee Inconsistent lateral rotation tibia
Foot /
ankle
Weight is shifted to toes and at toe off only the first
toe is in contact., supination of subtalar joint.
Thorax Translation on the ipsilaterior side.
Shoulder Moving forward.

34. DETERMINANTS OF GAITDETERMINANTS OF GAIT
►Six optimizations used to minimizeSix optimizations used to minimize
excursion of CG in vertical & horizontalexcursion of CG in vertical & horizontal
planesplanes
►Reduce significantly energy consumption ofReduce significantly energy consumption of
ambulationambulation
►The six determinants areThe six determinants are
 Lateral pelvis tiltLateral pelvis tilt
 Knee flexionKnee flexion
 Knee, ankle and foot interactionsKnee, ankle and foot interactions
 Forward and backward rotation of pelvisForward and backward rotation of pelvis
 Physiological valgus of kneePhysiological valgus of knee

35. DETERMINANTS OF GAITDETERMINANTS OF GAIT
1)1) Pelvic rotationPelvic rotation::
 Forward rotation of the pelvis in the horizontalForward rotation of the pelvis in the horizontal
plane approx. 8o on the swing-phase sideplane approx. 8o on the swing-phase side
 Reduces the angle of hip flexion & extensionReduces the angle of hip flexion & extension
 Enables a slightly longer step-length w/o furtherEnables a slightly longer step-length w/o further
lowering oflowering of CGCG

36. (2)(2) Pelvic tiltPelvic tilt::
 5 degree dip of the swinging side (i.e. hip5 degree dip of the swinging side (i.e. hip
adduction)adduction)
 In standing, this dip is a positive Trendelenberg signIn standing, this dip is a positive Trendelenberg sign
 Reduces the height of the apex of the curve of CGReduces the height of the apex of the curve of CG

37. ((3)3) Knee flexion in stance phaseKnee flexion in stance phase::
 Approx. 20o dipApprox. 20o dip
 Shortens the leg in the middle of stance phaseShortens the leg in the middle of stance phase
 Reduces the height of the apex of the curve ofReduces the height of the apex of the curve of
CGCG

38. (4)(4) Ankle mechanismAnkle mechanism::
 Lengthens the leg at heel contactLengthens the leg at heel contact
 Smoothens the curve of CGSmoothens the curve of CG
 Reduces the lowering of CGReduces the lowering of CG

39. (5)(5) Foot mechanismFoot mechanism::
 Lengthens the leg at toe-off as ankle movesLengthens the leg at toe-off as ankle moves
from dorsiflexion to plantarflexionfrom dorsiflexion to plantarflexion
 Smoothens the curve of CGSmoothens the curve of CG
 Reduces the lowering of CGReduces the lowering of CG

40. ►Physiological valgus of knee
Reduces the base of support, so only little lateral
motion of pelvis is necessary.

41. FACTORS AFFECTING GAIT
►Age
►Gender
►Assistive devices
►Disease states
►Muscle weakness or paralysis
►Asymmetries of the lower
extremities
►Injuries and malalignments

42. GAIT EXAMINATION
►Take a history
►Couch examination
►Static examination
►Allow patient time to relax
►Reasonable length walkway - gait pattern
changes before & after turn
►Various systematic ways
►Look for the obvious!

43. COUCH EXAMINATION
►Observe deformities & lesions
►Check ROM’s
►Check muscle tightness/strength
►Neurological & vascular assessment

44. STATIC EXAMINATION
►Feet non-weight bearing (hanging) with
weight bearing
►Standing from front
 Shoulders, hips, knees, feet
 From behind
 Shoulders, hips, calcaneus

45. GENERAL POINTS
►Is the gait fast or slow?
►Is it smooth?
►Does the patient appear
relaxed & comfortable or
pained?
►Is it noisy?

46. FEET

47. ►Is the 1st MPJ functioning properly?
►Are the toes bearing weight?
►When is the heel lifting?
►Is toe off through the hallux?
►Does the swing phase appear normal?
►Are the feet too close or is the base of gait
wide?
FEET

48. LEGS
►Are the knees pointing forwards?
►Is there genu valgum or varum?
►Is there tibial varum present?
►Do they appear internally or externally
rotated?
►Knees from the side – are they fully
extending?

49. HIPS & BODY

50. HEAD & SHOULDERS
►Are the shoulders level?
►Do the arms swing equally?
►Does the head & neck appear normal?

51. Gait: Major points of observation.
1.Cadence
a. Symmetrical
b. Rhythmic
2.Pain
a. Where
b. When
3.Stride
a. Even/uneven
4.Shoulders
Dipping. Elevated,
depressed, protracted,
retracted
5.Trunk
a. Fixed deviation
b. Lurch
6.Pelvic
a. Anterior or posterior tilt
b. Hike
c. Level
7.Knee
a. Flexion, extension
b. Stability
8.Ankle
a. Dorsiflexion
b. Eversion, inversion
9.Foot
a. Heelstrike
10.Base
a. Stable/variable
b. Wide/narrow

52. COMMON GAITCOMMON GAIT
ABNORMALITIESABNORMALITIES
► Antalgic GaitAntalgic Gait
• Gait pattern in which stance phase onGait pattern in which stance phase on
affected side is shortenedaffected side is shortened
• Corresponding increase in stance onCorresponding increase in stance on
unaffected sideunaffected side
• Common causes: OA, Fx, tendinitisCommon causes: OA, Fx, tendinitis

53. Lateral Trunk bending/Lateral Trunk bending/
TrendelenbergTrendelenberg gaitgait
►Usually unilateralUsually unilateral
►Bilateral = waddling gaitBilateral = waddling gait
►Common causes:Common causes:
A. Painful hipA. Painful hip
B. Hip abductor weaknessB. Hip abductor weakness
C. Leg-length discrepancyC. Leg-length discrepancy
D. Abnormal hip jointD. Abnormal hip joint

56. Functional Leg-LengthFunctional Leg-Length
DiscrepancyDiscrepancy
►Swing leg: longer than stance legSwing leg: longer than stance leg
►4 common compensations:4 common compensations:
A. CircumductionA. Circumduction
B. Hip hikingB. Hip hiking
C. SteppageC. Steppage
D. VaultingD. Vaulting

57. Increased Walking BaseIncreased Walking Base
►Normal walking base: 5-10 cmNormal walking base: 5-10 cm
Common causes:Common causes:
►DeformitiesDeformities
►Abducted hipAbducted hip
►Valgus kneeValgus knee
InstabilityInstability
►Cerebellar ataxiaCerebellar ataxia
►Proprioception deficitsProprioception deficits

58. Inadequate DorsiflexionInadequate Dorsiflexion
Control/foot drop gaitControl/foot drop gait
►In stance phase (Heel contact – Foot flat):In stance phase (Heel contact – Foot flat):
Foot slapFoot slap
►In swing phase (mid-swing):In swing phase (mid-swing):
Toe dragToe drag
 Causes:Causes:
 Weak Tibialis Ant.Weak Tibialis Ant.
 Spastic plantarflexorsSpastic plantarflexors

59. Excessive knee extensionExcessive knee extension
►Loss of normal knee flexion during stanceLoss of normal knee flexion during stance
phasephase
►Knee may go into hyperextensionKnee may go into hyperextension
►Genu recurvatumGenu recurvatum: hyperextension deformity: hyperextension deformity
of kneeof knee
Common causes:Common causes:
 Quadriceps weakness (mid-stance)Quadriceps weakness (mid-stance)
 Quadriceps spasticity (mid-stance)Quadriceps spasticity (mid-stance)
 Knee flexor weakness (end-stance)Knee flexor weakness (end-stance)

60. Others pathological gaits
►Arthrogenic gait ( stiff hip or knee)
►Contracture gait
►Gluteus maximus gait
►Planter flexor gait
►Scissors gait

61. Neurological gait
►Ataxic gait
►Parkinsons gait
►Hemiplegic gait
►Spectic diplegic
►Myopatic gait
►Hyperkinetic gait

62. RUNNING GAIT
► Require greater balance, muscle
strength, ROM than normal walking.
► Difference b/w running and walking
► Reduced BOS
► Absence of double support
► More coordination and strength
needed
► Muscle must generate higher energy
bout to raise HAT higher than in
normal walking.
► Divided into flight and support phase.

63. STAIR GAIT
► Ascending and
descending stairs
is a basic body
movement
required for ADL
► Stair gait involved
stance and swing
phase

64. kinematics
► SWING PHASE(36%)
• Foot clearance
• Foot placement
► STANCE
PHASE(64%)
• Weight acceptance
• Pull up
• Forward continuance

68. SIMILARITIES & DIFFERNCES BETWEEN
LEVEL GROUND GAIT AND STAIR GATE
►Similarities to Walking
Double support periods
Ground reaction forces have double peak
Cadence similar
Support moment is similar (always positive with
two peaks)

69. Differences with Walking
► More hip and knee flexion
► Greater Rom needed
► Peak forces slightly higher
► Centre of pressure is concentrated under
metatarsals, rarely near heel
► Step height and tread vary from stairway to
stairway
► Railings may be present

70. ……….. THANK
YOU ….