1. GAIT
JAYANT SHARMA
M.S.,D.N.B.,M.N.A.M.S.

2. DEFINITION
Normal Gait =
– Series of rhythmical , alternating
movements of the trunk & limbs which
result in the forward progression of the
center of gravity
– series of ‘controlled falls’

3. Gait Cycle
–Single sequence of functions by one
limb
–Begins when reference font contacts
the ground
–Ends with subsequent floor contact of
the same foot

4. Gait Cycle - Definitions:
Step Length =
–Distance between corresponding
successive points of heel contact of
the opposite feet
–Rt step length = Lt step length (in
normal gait

5. Stride Length =
–Distance between successive points of
heel contact of the same foot
–Double the step length (in normal gait)

6. Walking Base =
–Side-to-side distance between the line
of the two feet
–Also known as ‘stride width’

7. Normal Gait
STANCE (60-62% gait cycle)
Initial Contact: The moment the foot contacts
the ground.
Loading Response: Weight is rapidly transferred
onto the outstretched limb, the first period of
double-limb support.
Midstance: The body progresses over a
single, stable limb.
Terminal Stance: Progression over the stance
limb continues. The body moves ahead of the
limb and weight is transferred onto the forefoot.
Pre-swing: A rapid unloading of the limb occurs
as weight is transferred to the contralateral
limb, the second period of double-limb support

8. SWING (38-40% gait cycle)
Initial Swing: The thigh begins to
advance as the foot comes up off the
floor.
Mid Swing: The thigh continues to
advance as the knee begins to extend, the
foot clears the ground.
Terminal Swing: The knee extends, the
limb prepares to contact the ground.

9. The contact period
- Objective: adapt to terrain, shock
absorption, forward progression
- 0-10% of gait cycle (HC to FFC)
- at HC: hip flexed, knee extended, ankle
in neutral (90°), STJ supinated
- from HC to FFC: knee flexes, ankle
plantarflexes, STJ pronates
Muscle activity:
- long extensors decelerate plantarflexion
- tibialis posterior decelerates pronation
- gastrocnemius decelerates internal tibial
rotation

10. Midstance
- objective: progression over stationary foot, limb
and trunk stability
- 10 - 30% of gait cycle (FFC to HO)
- knee and hip start to extend
- subtalar joint pronation should have ceased (ie.
neutral)
Muscle activity:
- tibialis posterior and soleus start to supinate
STJ
- peroneus longus stabilizes first ray
- triceps surae decelerate forward displacement
of tibia, and plantarflex ankle joint

11. Propulsion
- objective: forward progression, foot becomes
'rigid lever'
- 30 - 60% of gait cycle (HO to TO)
- knee flexes, ankle plantarflexes
- subtalar joint rapidly supinates
- first ray plantarflexes
- 1st MPJ dorsiflexes: toe-off through tip of hallux
Muscle activity:
- soleus and tibialis posterior assist heel lift
- peroneus longus stabilizes first ray
- FHL, FHB, AbH, AdH stabilize hallux
- EHL dorsiflexes hallux

12. Swing phase
- objective: forward progression, ground
clearance
- 60-100% of gait cycle
- hip continues to flex
- knee extends from flexed position
- ankle dorsiflexes
- STJ slightly pronated at toe-off
Muscle activity:
- long extensors dorsiflex foot for toe clearance
- tibialis anterior dorsiflexes the first ray

14. The Functional Phases of the
Gait Cycle
Stance (62%)
IC LR
Weight Acceptance
MS TS
Single Limb
Support
Swing (38%)
PSw ISw MSw TSw
Swing Limb
Advance

15. Normal Stride Characteristics
A. Cadence: steps / timeAdult: approx. 2
steps/sec
Females (20 - 69 years old): 121 ∀ 8.5
steps/min
Males (20 - 69 years old): 111 ∀ 7.6
steps/min
Cadence =
– Number of steps per unit time
– Normal: 100 – 115 steps/min
– Cultural/social variations

16. Comfortable Walking Speed
(CWS) =
–Least energy consumption per unit
distance
–Average= 80 m/min (~ 5 km/h , ~
3 mph)

17. –Velocity =
Distance covered by the body in unit
time
Usually measured in m/s
Instantaneous velocity varies during
the gait cycle
Average velocity (m/min) = step length
(m) x cadence (steps/min)

18. Phases:
Stance Phase: Swing Phase:
reference limb reference limb
in contact not in
contact
with the floor with the floor

19. Support:
(1) Single Support: only one foot in contact
with the floor
(2) Double Support: both feet in contact
with floor

20. Stance phase:
1. Heel contact: ‘Initial contact’
2. Foot-flat: ‘Loading response’, initial contact of
forefoot w. ground
3. Midstance: greater trochanter in alignment w.
vertical bisector of foot
4. Heel-off: ‘Terminal stance’
5. Toe-off: ‘Pre-swing’

21. Swing phase:
1. Acceleration: ‘Initial swing’
2. Midswing: swinging limb overtakes the limb in
stance
3. Deceleration: ‘Terminal swing’

23. Time Frame:
A. Stance vs. Swing:
Stance phase = 60% of gait cycle
Swing phase = 40%
B. Single vs. Double support:
Single support= 40% of gait cycle
Double support= 20%

24. With increasing walking speeds:
Stance phase: decreases
Swing phase: increases
Double support: decreases
Running:
By definition: walking without double support
Ratio stance/swing reverses
Double support disappears. ‘Double swing’
develops

25. Path of Center of Gravity
Center of Gravity (CG):
– midway between the hips
– Few cm in front of S2
Least energy consumption if CG
travels in straight line

27. Path of Center of Gravity
Vertical displacement:
Rhythmic up & down
movement
Highest point: midstance
Lowest point: double
support
Average displacement:
5cm
Path: extremely smooth
sinusoidal curve

28. Lateral displacement:
Rhythmic side-to-side
movement
Lateral limit: midstance
Average displacement:
5cm
Path: extremely smooth
sinusoidal curve

29. Overall
displacement:
Sum of vertical &
horizontal
displacement
Figure ‘8’
movement of CG
as seen from AP
view

30. Determinants of Gait :
Six optimizations used to minimize
excursion of CG in vertical &
horizontal planes
Reduce significantly energy
consumption of ambulation
Classic papers: Sanders, Inman
(1953)

31.  Pelvic rotation:
Forward rotation of the pelvis in the horizontal
plane approx. 8o on the swing-phase side
Reduces the angle of hip flexion & extension
Enables a slightly longer step-length w/o
further lowering of CG

32. Pelvic tilt:
5o dip of the swinging side (i.e. hip adduction)
In standing, this dip is a positive
Trendelenberg sign
Reduces the height of the apex of the curve of
CG

33. Knee flexion in stance phase:
Approx. 20o dip
Shortens the leg in the middle of stance
phase
Reduces the height of the apex of the
curve of CG

34. Ankle mechanism:
Lengthens the leg at heel contact
Smoothens the curve of CG
Reduces the lowering of CG

35. Foot mechanism:
Lengthens the leg at toe-off as
ankle moves from dorsiflexion to
plantarflexion
Smoothens the curve of CG
Reduces the lowering of CG

36. Lateral displacement of body:
The normally narrow width of the
walking base minimizes the lateral
displacement of CG
Reduced muscular energy consumption
due to reduced lateral acceleration &
deceleration

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

38. The force that the foot
exerts on the floor due
to gravity & inertia is
opposed by the ground
reaction force
Ground reaction force
(RF) may be resolved
into horizontal (HF) &
vertical (VF)
components.
Understanding joint
position & RF leads to
understanding of
muscle activity during
gait

39. At initial heel-contact: ‘heel
transient’
At heel-contact:
Ankle: DF
Knee: Quad
Hip: Glut. Max&Hamstrings

42. Low muscular demand:
– ~ 20-25% max. muscle strength
– MMT of ~ 3+

43. COMMON GAIT ABNORMALITIES
A. Antalgic Gait
B. Lateral Trunk bending
C. Functional Leg-Length
Discrepancy
D. Increased Walking Base
E. Inadequate Dorsiflexion Control
F. Excessive Knee Extension

44. Hip abductor load & hip joint reaction force

45. Hip abductor load & hip joint reaction force

46. Swing leg: longer than stance leg
4 common compensations:
A. Circumduction
B. Hip hiking
C. Steppage
D. Vaulting
Functional Leg-Length Discrepancy

47. Increased Walking Base
Normal walking base: 5-10 cm
Common causes:
– Deformities
Abducted hip
Valgus knee
– Instability
Cerebellar ataxia
Proprioception deficits

48. Inadequate Dorsiflexion Control
In stance phase (Heel contact – Foot
flat):
Foot slap
In swing phase (mid-swing):
Toe drag
Causes:
– Weak Tibialis Ant.
– Spastic plantarflexors

49. Excessive knee extension
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)

50. Lateral Trunk bending
Trendelenberg gait
Usually unilateral
Bilateral = waddling gait
Common causes:
A. Painful hip
B. Hip abductor weakness
C. Leg-length discrepancy
D. Abnormal hip joint

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

53. Velocity: distance/time
Adult: 1.4 m/sec
Females (20 - 69 years old): 79.3 ∀
9.5 m/min
Males (20 - 69 years old): 82.1 ∀
10.3 m/min

54. C. Stride length: right heel strike to
right heel strike
Adult: 1.5 m
Females (20 - 69 years old): 1.32 ∀
.13 m
Males (20 - 69 years old): 1.48 ∀ .15
m

57. Abnormalities during Weight Acceptance:
Joint Deviation: Possible Cause
Trunk
Backward lean: To decrease demand
on hip extensors (glut max)
Forward lean: Due to increased hip
flexion (joint contracture or mm weakness)
Lateral Lean: R/L Weak hip abductors
Pelvis
Contralateral drops: Weak hip
abductors on reference limb
Ipsilateral drops: Compensation for
shortened limb

58. Hip Excessive flexion:
Hip flexion contracture, excessive knee flexion
Limited flexion: Weakness of hip flexors, decreased
hip flexion
Knee
Excessive flexion: Knee pain, weak quads, short leg
on opposite side
Hyperextension: Decreased dorsiflexion, weak quads
Extension thrust: Intention to increase limb stability
Ankle
Forefoot contact: Heel pain, excessive knee
flexion, pf contracture
Foot flat contact: Dorsiflexion contracture, weak
dorsiflexors
Foot slap: Weak dorsiflexors
Toes Up: Compensation for weak anterior tib

59. Abnormalities during Single Limb Support:
Joint Deviation: Possible Cause
Trunk
Backward lean: To decrease demand
on hip extensors (glut max)
Forward lean: Due to increased hip
flexion (joint contracture or mm
weakness)
Lateral Lean: R/L Weak hip
abductors

60. Pelvis
Contralateral drops: Weak hip abductors on
reference limb
Ipsilateral drops: Compensation for shortened limb
Anterior Pelvic Tilt: Hip flexion contracture
Hip
Limited flexion: Weakness of hip flexors, decreased
hip flexion
Internal Rotation: Weak external rotators, femoral
anteversion
External Rotation: Retroversion, limited dorsiflexion
Abduction: Reference limb longer
Adduction: Secondary to contralateral pelvic drop

61. Knee
Excessive flexion: Knee pain, weak quads,
short leg on opposite side
Hyperextension: Decreased dorsiflexion,
weak quads
Extension thrust: Intention to increase
limb stability
Wobbles: Impaired proprioception
Varus: Joint instability, bony deformity
Valgus: Lateral trunk lean, Joint
instability, bony deformity

62. Ankle
Excessive plantarflexion: Weak
quads, Impaired
proprioception, ankle pain
Early heel off: Tight dorsiflexors,
Increased pronation: STJ deformity,
Toes Up: Compensation for weak
anterior tib

63. Abnormalities during Swing Limb Advance:
Joint Deviation: Possible Cause
Trunk
Backward lean: To decrease demand on hip
extensors (glut max)
Forward lean: Due to increased hip flexion (joint
contracture or mm weakness)
Lateral Lean: R/L Weak hip abductors
Pelvis
Hikes: Clear swing limb
Ipsilateral drops: Weak hip abductors on
contralateral side
Hip
Limited flexion: Weakness of hip
flexors, decreased hip flexion, hip pain

64. Knee
Limited flexion: Excess hip flexion, knee pain
Excess flexion: Knee contracture, weak quads
Ankle
Excessive plantarflexion: Weak quads, Impaired
proprioception, ankle pain
Drag: Secondary to limited hip flexion, knee flexion or excess
pf
Contralateral Vaulting: Compensation for limited flexion of
swing or long swing
limb
Toes
Inadequate extension:Limited joint motion, forefoot pain, no
heel off
Clawed/hammered: Imbalance of long toe extensors and
intrinsics, weak pf

65. Running Gait
Variations from walking
STANCE (30 - 40%)
Foot Strike:
Mid-support:
Take-off (propulsion)
SWING (60 - 70%)
Follow through:
Forward swing:
Foot descent:

67. list of common overuse injuries associated
with poor gait biomechanics:
Shin splints
Plantar fasciits
Iliotibial band syndrome (runners knee)
Patella tendonitis (jumpers knee)
Patello-femoral knee pain
Achilles tendonitis
Lower back pain

71. Shock absorption and energy conservation are
important aspects of efficient gait. Altered joint
motion or absent muscle forces may increase
joint reaction (contact) forces and lead
subsequently to additional pathology. In early
stance, nearly 60% of one's body weight is
loaded abruptly (less than 20 milliseconds) onto
the ipsilateral limb. This abrupt impact is
attenuated at each of the lower extremity joints.
Loading response plantar flexion is
passive, substantially restrained by eccentric
work of pretibial muscles. The absorptive work by
pretibial muscles delays forefoot contact until late
in the initial double support period (7-8% GC).

72. At initial contact, external (ground
reaction) forces applied to the contact foot
produce a tendency toward knee flexion.
Repositioning the knee (recurvatum)
increases knee mechanical stability, but at
the cost of increased contact forces and
shock generation. A balance between knee
stability and shock absorption is achieved
by eccentric quadriceps contractions
during loading response. The impact of
loading is minimized at the hip during
single support through hip abductor
muscle contraction.

73. Energy conservation
Ambulation always is associated with
metabolic costs. These costs are
relatively minor in normal adults
performing free speed level walking.
The self-selected walking speed in
normal adults closely matches the
velocity that minimizes metabolic
work.