GAIT
movements that produces locomotion
Gait Cycle or Stride
A single gait cycle or stride is defined:
Period when 1 foot contacts the ground to when that
same fo...
Stance Phase
Principal events during the stance phase
1. Heel strike
2. Foot-flat (followed by opposite heel-off)
3. Heel-...
Principal events during the stance phase:
heel-strike, foot-flat, heel-off, toe-off
4
Activities occur in stance phase
Traditional Method
1. Heel Strike : double support
2. Foot flat : total contact
3. Mid-st...
Initial Contact
Phase 1
The moment when the
red foot just touches the
floor.
The heel (calcaneous) is
the first bone of th...
Static Positions at Initial Contact
Shoulder is extended
Pelvis is rotated left
Hip is flexed and
externally rotated
Knee ...
Loading Response
Phase 2
The double stance period
beginning
Body wt. is transferred
onto the red leg.
Phase 2 is important...
Static Positions at Loading Response
Shoulder is slightly
extended
Pelvis is rotated left
hip is flexed and slightly
exter...
Mid-stance
Phase 3
single limb support
interval.
Begins with the lifting of
the blue foot and
continues until body
weight ...
Static Positions at Midstance
Shoulder is in neutral
Pelvis is in neutral
rotation
Hip is in neutral
Knee is fully extende...
Terminal Stance
Phase 4
Begins when the red heel
rises and continues until
the heel of the blue foot
hits the ground.
Body...
Static Positions at Terminal Stance
Shoulder is slightly
flexed
Pelvis is rotated left
Hip is extended and
internally rota...
Pre-swing
Phase 5
The second double
stance interval in the gait
cycle.
Begins with the initial
contact of the blue foot
an...
Static Positions at Pre-swing
Shoulder is flexed
Pelvis is rotated right
Hip is fully extended
and internally rotated
Knee...
Swing phase
Principal events during the Swing phase
1. Acceleration: ‘Initial swing’
2. Mid swing : swinging limb overtake...
Activities occur in swing phase
Traditional Method
1. Acceleration : starts
immediately from toe
off
2. Mid stance : swing...
Initial Swing
Phase 6
Begins when the red foot
is lifted from the floor
and ends when the red
swinging foot is opposite
th...
Static Positions at Initial Swing
Shoulder is flexed
Spine is rotated left
Pelvis is rotated right
hip is slightly extende...
Mid-swing
Phase 7
Starts at the end of the
initial swing and
continues until the red
swinging limb is in front
of the body...
Static Positions at Mid-swing
Shoulder is neutral
Spine is neutral
Pelvis is neutral
Hip is neutral
Knee is flexed 60-90°
...
Terminal Swing
Phase 8
Begins at the end of mid-
swing and ends when the
foot touches the floor.
Limb advancement is
compl...
Static Positions at Terminal Swing
Shoulder is extended
Spine is rotated right
Pelvis is rotated left
Hip is flexed and
ex...
DISTANCE VARIABLES
Step length
Stride length
Width of walking base
Degree of toe out
24
Step Length
Distance between corresponding successive points
of heel contact of the opposite feet
Rt step length = Lt step...
Stride Length
Distance between successive points of heel contact
of the same foot
Double the step length (in normal gait)
...
Walking Base
Side-to-side distance between the line of the two feet
Also known as ‘stride width’
Normal is 3.5 inches
27
Degree of toe out
Represents the angle of foot placement
It is the angle formed by each foot’s line of progression
and a l...
TEMPORAL VARIABLES
Stance Time : Is the amount of time that elapses
during the stance phase of one extremity in a gait cyc...
TEMPORAL VARIABLES
Cadence
Number of steps per unit time
Normal: 100 – 115 steps/min
Cultural/social variations
Velocity
D...
DETERMINANTS OF GAIT
1. Lateral pelvic tilt
2. Knee flexion
3. Knee, ankle, foot interactions
4. Pelvic forward and backwa...
Lateral pelvic tilt
During mid-stance the COG
reaches the peak level & the total
body supported by one lower
extremity
The...
Knee flexion
Another DG which
helps to reduce the
COG during mid-
stance
As the hip joint passes
over the foot during
the ...
Knee, ankle, foot interactions
KAF interaction prevent
abrupt hike in COG from
heel strike to foot flat
After heel strike ...
Pelvic forward and backward rotation
Forward rotn. occurs in swing
phase
It starts during acceleration and
ends in deceler...
Physiologic valgus of knee
Is minimised by having
a narrow walking base
i.e. feet closer together
than are hips.
Therefore...
Efficiency, and energy considerations
• Walking is very energy-
efficient: little ATP is required.
• This is because of va...
A conventional pendulum –
energy interconversion
P.E. – Potential energy
K.E. – Kinetic energy
Three points on a pendulum
...
Conventional pendulum action
during the swing phase
The legs move as conventional pendulums during the swing
phase (with a...
An “inverted” pendulum
The pendulum
“bounces”
backwards and
forwards, using
the springs.
40
“Inverted” pendulum action during the stance phase
During the stance phase, the leg can be viewed as an “inverted
pendulum...
Positive & negative Work
At a cadence of 105-112 steps/minute
between heel strike and foot flat
1. a brief burst of positi...
Forces
The principal forces are:
body weight (BW)
ground reaction force (GRF)
muscle force (MF)
BW and GRF are external fo...
Vitally important point:
Muscle forces can only influence
the movement of the body as a
whole indirectly, by their effects...
Walking as a “controlled fall”
One way of beginning to understand the mechanics of
walking is to view the movements as a “...
Walking as a controlled fall: forces
involved
When starting to move, we lean forward (MF)
As the body starts to fall (BW),...
Body weight
Always acts vertically downwards from the CoM
If its line of action does not pass through a joint, it
will pro...
Ground reaction force
The force that the foot exerts on
the floor due to gravity & inertia
is opposed by the ground reacti...
Muscle force
In gait, as in all human movement, muscle
activation generates internal joint moments
(torques) that:
Contrib...
Center Of Pressure (COP)
Represents the centroid of foot
forces on the floor
This is an idealization, because
pressures ar...
Muscles, Joints, and Forces
Eccentric
Concentric
Ground Reaction Force
51
Sagittal Plane Analysis
Initial Contact
Hip 30° of flexion,
knee is extended
ankle is neutral
GRF
Ant. to hip, drives the ...
Sagittal Plane Analysis
Loading Response
Hip extension 25°
Knee flexion to 20°
Ankle plantar flexion to 10°
Contralateral ...
Sagittal Plane Analysis
Mid Stance
GRF through hip, knee, and
ankle
Muscular activity terminates
Hip and knee stability pr...
Sagittal Plane Analysis
Terminal Stance
No change in GRF
Free forward fall
Strong activation of
gastrosoleus complex
55
Sagittal Plane Analysis
Pre-Swing
Hip 20° of hyperextansion
Knee 30° of flexion
Ankle 20° of plantarflexion
Toes 50° of hy...
Sagittal Plane Analysis
Initial Swing
Hip 0-30° of flexion
Knee from 30-60° of flexion and
extension from 60-30°
Ankle 20°...
Sagittal Plane Analysis
Mid Swing
Tibialis anterior fires to
maintain foot position
Knee extension and hip
flexion continu...
Sagittal Plane Analysis
Terminal Swing
Decelerate knee extension
and hip flexion
Hamstrings
Gluteus max
Quads co-contract
...
Frontal Plane Analysis
IC to LR
Pelvis : forward rotn.
Hip : med. rotn. of femur
Knee : increased valgus
Ankle : increased...
Frontal Plane Analysis
LR to Mid-stance
Pelvis : Rt. side rotating
backward to reach neutral.
Lat. tilt towards the swingi...
Frontal Plane Analysis
Mid-stance to TS
Pelvis : Rt. side move
Posteriorly
Hip : Lat. rotn. of femur and
adduction
Knee : ...
Frontal Plane Analysis
TS to PS
Pelvis : Lt. side move
forward, lat. tilting to swing
side ends as double support
begins
H...
Frontal Plane Analysis
IS to MS
Pelvis : Lat. pelvic tilt to the
rt. Right side move forward
Hip : Lat. rotn to med. rotn....
Frontal Plane Analysis
MS to TS
Pelvis : Rt. side move
anteriorly
Hip : Lat. tilting to the left
med. rotn.
Knee : Med. ro...
A word on running
Walking is biomechanically like a
pendulum, KE to PE to KE
Running is biomechanically like a
spring
No d...
Running: swing phase
Muscular rather than pendular
motion at hip.
Knee flexion, and ankle
dorsiflexion, bring CoM of the l...
Running: support phase
Hip: slight flexion followed by
extension. Gluteus maximus
activity initially eccentric
Knee: degre...
STAIR GAIT
Stair Ascent
Stance Phase
1. Weight acceptance
2. Pull up
3. Forward continuance
Swing Phase
1. Foot clearance
...
STAIR GAIT
Stair Descending
Swing Phase
1. Foot clearance
2. Foot Placement
Stance Phase
1. Weight acceptance
2. Pull up
3...
Sagittal Plane analysis of Stair gait
WA to PU
Hip : Extension from 60-
30° of flexion
Knee : Extension from
80-35° of fle...
Sagittal Plane analysis of Stair gait
PU to FC
Hip : extension 30 - 5° of
flexion, flexion 5-20° of
flexion
Knee : Extensi...
Sagittal Plane analysis of Stair gait
Foot clearance through foot
placement
Hip : flexion 10-20° to 40-
60° of flexion, ex...
FACTORS INFLUENCING GAIT
Age
Gender
Assistive devices
abnormalities
74
FACTORS INFLUENCING GAIT
Age
A toddler has a higher COG, wider BOS, decreased
single leg support time, a shorter step leng...
FACTORS INFLUENCING GAIT
Gender
Men Women
Joint angle increases as speed
increases
Gait speed faster i.e.. 118-134
cm/s
St...
FACTORS INFLUENCING GAIT
Assistive devices
Canes are typically been used on the
contralateral side to an affected limb to ...
COMMON GAIT ABNORMALITIES
A. Deformity(Contracture)
B. Muscle Weakness
C. Sensory Loss
D. Pain
E. Impaired Motor Control(S...
Ankle and Foot Gait Deviation
79
Knee Abnormal Gait
80
Knee Abnormal Gait
81
Knee Abnormal Gait
82
Knee Abnormal Gait
83
Hip Abnormal Gait
84
Hip Abnormal Gait
85
Pelvis and Trunk Pathological Gait
86
Pelvis and Trunk Pathological Gait
87
Pelvis and Trunk Pathological Gait
88
Pelvis and Trunk Pathological Gait
89
COMMON TYPES OF ABNORMAL GAITS
Scissor gait
Antalgic gait
Cerebellar ataxia
Festinating gait
Pigeon gait
Propulsive gait
S...
Scissor gait
Hypertonia in the legs, hips and pelvis means these areas
become flexed, to various degrees, giving the appea...
Antalgic gait
Person tries to avoid pain associated with the
ambulation. Often quick, short and soft foot
steps.
92
Ataxic gait
Spinal - proprioceptive pathways of the spine or
brainstem are interrupted. There is loss of
position and moti...
Festinating gait
The patient has difficulty starting, but also has
difficulty stopping after starting. This is due to
musc...
Pigeon gait
In-toe gait is a very common problem among
children and even adults. Fortunately, most in-
toeing that is seen...
Propulsive gait
Disturbance of gait typical of Parkinsonism in
which, during walking, steps become faster and
faster with ...
Steppage gait
A manner of walking in which the advancing
foot is lifted high so that the toes clear the
ground. Steppage g...
Stomping gait
Sensory ataxia presents with an unsteady
"stomping" gait with heavy heel strikes, as well
as postural instab...
Spastic gait
An unbalanced muscle action of certain muscle
groups leads to deformity. Prime example is
"Scissor gait" - ad...
Myopathic gait
The "waddling" is due to the weakness of the
proximal muscles of the pelvic girdle.
The patient uses circum...
Magnetic gait
Normal pressure hydrocephalus (NPH) gait
disturbance is often characterized as a "magnetic
gait," in which f...
Trendelenburg gait
The Trendelenburg gait is an abnormal gait caused by
weakness of the abductor muscles of the lower
limb...
Hemiplegic Gait Demonstration
The patient has unilateral
weakness and spasticity with
the upper extremity held in
flexion ...
Diplegic Gait Demonstration
The patient has spasticity in the
lower extremities greater than the
upper extremities. The hi...
Neuropathic Gait Demonstration
This type of gait is most
often seen in peripheral
nerve disease where the
distal lower ext...
Myopathic Gait Demonstration
With muscular diseases, the
proximal pelvic girdle
muscles are usually the most
weak. Because...
Parkinsonian Gait Demonstration
This type of gait is seen
with rigidity and
hypokinesia from basal
ganglia disease. The
pa...
Choreiform Gait Demonstration
This is a hyperkinetic gait
seen with certain types of
basal ganglia disorders. There
is int...
Ataxic Gait Demonstration
The patient's gait is wide-
based with truncal instability
and irregular lurching steps
which re...
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Gait, movements that produce locomotion

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Gait, movements that produce locomotion

  1. 1. GAIT movements that produces locomotion
  2. 2. Gait Cycle or Stride A single gait cycle or stride is defined: Period when 1 foot contacts the ground to when that same foot contacts the ground again Each stride has 2 phases: Stance Phase Foot in contact with the ground Swing Phase Foot NOT in contact with the ground 2
  3. 3. Stance Phase Principal events during the stance phase 1. Heel strike 2. Foot-flat (followed by opposite heel-off) 3. Heel-rise (followed by opposite heel strike) 4. Toe-off 3
  4. 4. Principal events during the stance phase: heel-strike, foot-flat, heel-off, toe-off 4
  5. 5. Activities occur in stance phase Traditional Method 1. Heel Strike : double support 2. Foot flat : total contact 3. Mid-stance : total weight bearing 4. Heel-off : heel clears the ground 5. Toe-off : toe clears the ground RLA Method 1. Initial contact : heel strike 2. Loading response : double support 3. Mid-stance : begins when contralateral L/E clears the ground & when the body come straight line to supporting limb 4. Terminal stance : end of mid stance to initial contact of CL L/E 5. Pre-swing : period of clearance from the ground 5
  6. 6. Initial Contact Phase 1 The moment when the red foot just touches the floor. The heel (calcaneous) is the first bone of the foot to touch the ground. Meanwhile, the blue leg is at the end of terminal stance. 6
  7. 7. Static Positions at Initial Contact Shoulder is extended Pelvis is rotated left Hip is flexed and externally rotated Knee is fully extended Ankle is dorsiflexed Foot is supinated Toes are slightly extended 7
  8. 8. Loading Response Phase 2 The double stance period beginning Body wt. is transferred onto the red leg. Phase 2 is important for shock absorption, weight-bearing, and forward progression. The blue leg is in the pre-swing phase. 8
  9. 9. Static Positions at Loading Response Shoulder is slightly extended Pelvis is rotated left hip is flexed and slightly externally rotated knee is slightly flexed ankle is plantar flexing to neutral foot is neutral Toes are neutral 9
  10. 10. Mid-stance Phase 3 single limb support interval. Begins with the lifting of the blue foot and continues until body weight is aligned over the red (supporting) foot. The red leg advances over the red foot The blue leg is in its mid- swing phase. 10
  11. 11. Static Positions at Midstance Shoulder is in neutral Pelvis is in neutral rotation Hip is in neutral Knee is fully extended Ankle is relatively neutral Foot is pronated Toes are neutral 11
  12. 12. Terminal Stance Phase 4 Begins when the red heel rises and continues until the heel of the blue foot hits the ground. Body weight progresses beyond the red foot 12
  13. 13. Static Positions at Terminal Stance Shoulder is slightly flexed Pelvis is rotated left Hip is extended and internally rotated Knee is fully extended Ankle is dorsi flexed Foot is slightly supinated Toes are neutral 13
  14. 14. Pre-swing Phase 5 The second double stance interval in the gait cycle. Begins with the initial contact of the blue foot and ends with red toe- off. Transfer of body weight from ipsilateral to opposite limb takes place. 14
  15. 15. Static Positions at Pre-swing Shoulder is flexed Pelvis is rotated right Hip is fully extended and internally rotated Knee is fully extended Ankle is plantar flexed Foot is fully supinated Toes are fully extended 15
  16. 16. Swing phase Principal events during the Swing phase 1. Acceleration: ‘Initial swing’ 2. Mid swing : swinging limb overtakes the limb in stance 3. Deceleration: ‘Terminal swing’ 16
  17. 17. Activities occur in swing phase Traditional Method 1. Acceleration : starts immediately from toe off 2. Mid stance : swing directly beneath body 3. Deceleration : knee extension and prepare for heel strike RLA Method 1. Initial swing : max. knee flexion 2. Mid swing : from max. knee flxn. to verticl. Postn. of tibia 3. Terminal swing : from verticl. Postn. of tibia to initial contact 17
  18. 18. Initial Swing Phase 6 Begins when the red foot is lifted from the floor and ends when the red swinging foot is opposite the blue stance foot. It is during this phase that a foot drop gait is most apparent. The blue leg is in mid- stance. 18
  19. 19. Static Positions at Initial Swing Shoulder is flexed Spine is rotated left Pelvis is rotated right hip is slightly extended and internally rotated Knee is slightly flexed Ankle is fully plantar flexed Foot is supinated Toes are slightly flexed 19
  20. 20. Mid-swing Phase 7 Starts at the end of the initial swing and continues until the red swinging limb is in front of the body Advancement of the red leg The blue leg is in late mid-stance. 20
  21. 21. Static Positions at Mid-swing Shoulder is neutral Spine is neutral Pelvis is neutral Hip is neutral Knee is flexed 60-90° Ankle is plantar flexed to neutral Foot is neutral Toes are slightly extended 21
  22. 22. Terminal Swing Phase 8 Begins at the end of mid- swing and ends when the foot touches the floor. Limb advancement is completed at the end of this phase. 22
  23. 23. Static Positions at Terminal Swing Shoulder is extended Spine is rotated right Pelvis is rotated left Hip is flexed and externally rotated Knee is fully extended Ankle is fully dorsi flexed Foot is neutral Toes are slightly extended 23
  24. 24. DISTANCE VARIABLES Step length Stride length Width of walking base Degree of toe out 24
  25. 25. Step Length Distance between corresponding successive points of heel contact of the opposite feet Rt step length = Lt step length (in normal gait) 25
  26. 26. Stride Length Distance between successive points of heel contact of the same foot Double the step length (in normal gait) 26
  27. 27. Walking Base Side-to-side distance between the line of the two feet Also known as ‘stride width’ Normal is 3.5 inches 27
  28. 28. Degree of toe out Represents the angle of foot placement It is the angle formed by each foot’s line of progression and a line intersecting the centre of the heel and the second toe Normal angle is 7°for men at free speed walking 28
  29. 29. TEMPORAL VARIABLES Stance Time : Is the amount of time that elapses during the stance phase of one extremity in a gait cycle Single support time : is the amount of time that elapses during the period when only one extremity is on the supporting surface in a gait cycle Double support time : is the amount of time that a person spends with both feet on the ground during one gait cycle Stride duration : is the amount of time it takes to accomplish one stride Step duration : is the amount of time spent during a single step 29
  30. 30. TEMPORAL VARIABLES Cadence Number of steps per unit time Normal: 100 – 115 steps/min Cultural/social variations Velocity Distance covered by the body in unit time Usually measured in cm/s Instantaneous velocity varies during the gait cycle Average velocity (m/min) = step length (m) x cadence (steps/min) Comfortable Walking Speed (CWS) Least energy consumption per unit distance Average= 80 m/min (~ 5 km/h , ~ 3 mph) 30
  31. 31. DETERMINANTS OF GAIT 1. Lateral pelvic tilt 2. Knee flexion 3. Knee, ankle, foot interactions 4. Pelvic forward and backward rotation 5. Physiologic valgus of knee DGs represents the adjustments made by above components that help to keep movements of body’s COG to minimum. They are credited with decreasing the vertical and lateral excursions of the body’s COG and therefore decreasing energy expenditure and making gait more efficient 31
  32. 32. Lateral pelvic tilt During mid-stance the COG reaches the peak level & the total body supported by one lower extremity The pelvis slopes downwards laterally towards the leg which is in swing phase. i.e. rotation about an anterior-posterior axis Only anatomically possible if the swing leg can be shortened sufficiently (principally by knee flexion) to clear the ground. Where this is not possible (e.g. through injury), the absence of pelvic tilt and pronounced movements of the upper body are obvious. 32
  33. 33. Knee flexion Another DG which helps to reduce the COG during mid- stance As the hip joint passes over the foot during the support phase, there is some flexion of the knee. This reduces vertical movements at the hip, and therefore of the trunk and head. 33
  34. 34. Knee, ankle, foot interactions KAF interaction prevent abrupt hike in COG from heel strike to foot flat After heel strike huge upward displacement of COG occurs This is reduced by Knee flexion, ankle plantar flexion & foot pronation. From mid stance to heel off there is sudden drop in COG Ankle plantar flexion, knee extension and foot supination maintain this 34
  35. 35. Pelvic forward and backward rotation Forward rotn. occurs in swing phase It starts during acceleration and ends in deceleration During mid-swing pelvis comes to neutral position Forward and backward rotation help to prevent further reduction in COG which started from mid- stance During deceleration both lower extremities lengthens This prevents in further reduction of COG 35
  36. 36. Physiologic valgus of knee Is minimised by having a narrow walking base i.e. feet closer together than are hips. Therefore less energy is used moving hip from side to side (less lateral movement needed to balance body over stance foot) Reduced lateral pelvic displacement 36
  37. 37. Efficiency, and energy considerations • Walking is very energy- efficient: little ATP is required. • This is because of various mechanisms that ensure the mechanical energy the body has is passed on from one step to the next. • The two forms of mechanical energy involved are •kinetic energy (energy due to movement •potential energy (energy due to position) Economy (J m-1) 37
  38. 38. A conventional pendulum – energy interconversion P.E. – Potential energy K.E. – Kinetic energy Three points on a pendulum swing are illustrated. As the pendulum swings away from the midpoint, in either direction, KE is progressively converted into PE At the extreme points in the swing, there is no KE at all and all the energy is present as PE 38
  39. 39. Conventional pendulum action during the swing phase The legs move as conventional pendulums during the swing phase (with a little assistance from the hip flexors). This reduces the amount of muscle energy needed to move the swinging leg forward It also accounts for the “natural” frequency of gait that has optimal energy efficiency Although the legs swing forwards much like pendulums, they are prevented from swinging backwards by foot strike. During the stance phase, the leg can be viewed as an “inverted pendulum”. This action also involves inter- conversion of potential and kinetic energy 39
  40. 40. An “inverted” pendulum The pendulum “bounces” backwards and forwards, using the springs. 40
  41. 41. “Inverted” pendulum action during the stance phase During the stance phase, the leg can be viewed as an “inverted pendulum”. The forward momentum of the body gives it the necessary initial angular velocity of rotation (taking the place of the “spring” on the previous slide). “Inverted” pendulum action also involves inter-conversion of potential and kinetic energy, but in this case (unlike a conventional pendulum) KE reaches a minimum at the midpoint of the motion, and PE is highest at that point. When reaching the endpoint of its “inverted swing” the stance leg does not swing back, as a real inverted pendulum would, because the foot is taken off the floor, the fulcrum transfers from the foot to the hip, and the leg swings again as a conventional pendulum. 41
  42. 42. Positive & negative Work At a cadence of 105-112 steps/minute between heel strike and foot flat 1. a brief burst of positive work (energy generation) occurs as the hip extensors contract concentrically 2. while the knee extensors perform negative work (energy absorption) by acting eccentrically to control knee flexion from foot flat through mid-stance 1. Negative work is done by plantar flexors as the leg rotates over the foot during the period of stance 2. Positive work of the knee extensors occurs during this period to extend the knee late stance and in early swing 1. Positive work of plantar flexors and hip flexors increase the energy level of the body In late swing 1. negative work is performed by the hip extensors as they work eccentrically to decelerate the leg in preparation for initial contact 42
  43. 43. Forces The principal forces are: body weight (BW) ground reaction force (GRF) muscle force (MF) BW and GRF are external forces; so the movement of the centre of mass (CoM) can be predicted from them alone. MF must be examined however if we wish to consider either of the following: movements of individual limbs or body segments, why GRF changes in magnitude and direction during the gait cycle. 43
  44. 44. Vitally important point: Muscle forces can only influence the movement of the body as a whole indirectly, by their effects on the GRF 44
  45. 45. Walking as a “controlled fall” One way of beginning to understand the mechanics of walking is to view the movements as a “controlled fall” When starting a walk, we lean forward, overbalancing from the equilibrium position. This gives the upper part of the body forwards (and downwards) motion As the body falls forwards, a leg is extended forwards and halts the fall At the same time, the other leg “kicks off” in order to keep the body moving forwards. This forward momentum carries the body forward into the next forward fall, i.e. the start of the next step 45
  46. 46. Walking as a controlled fall: forces involved When starting to move, we lean forward (MF) As the body starts to fall (BW), a leg is extended forwards and halts the fall (MF; GRF) At the same time, the other leg “kicks off, upwards and forwards” (MF; GRF) in order to keep the body moving forwards. This forward momentum carries the body forward into the next forward fall, i.e. the start of the next step 46
  47. 47. Body weight Always acts vertically downwards from the CoM If its line of action does not pass through a joint, it will produce a torque about that joint The torque will cause rotation at the joint unless it is opposed by another force (e.g. muscle, or ligament) BW contributes to GRF 47
  48. 48. Ground reaction force 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 Forces are typically resolved into: 1. Vertical Compression (z) 2. Anterior-Posterior Shear (y) 3. Medial-Lateral Shear (x) 48
  49. 49. Muscle force In gait, as in all human movement, muscle activation generates internal joint moments (torques) that: Contribute to ground reaction force Ensure balance Increase energy economy Allow flexible gait patterns Slow down and/or prevent limb movements Much muscle activity during gait is eccentric or isometric, rather than concentric 49
  50. 50. Center Of Pressure (COP) Represents the centroid of foot forces on the floor This is an idealization, because pressures are distributed all over It is important, because we want to know where the GRF is applied to the body When measured by a force plate, it is more correctly called the point of application of the GRF Plotting the COP as it moves under the foot: 1. Normal Path: Center of the calcaneus or slightly lateral, curving laterally and then medial (pronation) and ending between the 1st and second toes 2. Variable: Normal individuals can have many COP trajectories, just by changing the footgear 50
  51. 51. Muscles, Joints, and Forces Eccentric Concentric Ground Reaction Force 51
  52. 52. Sagittal Plane Analysis Initial Contact Hip 30° of flexion, knee is extended ankle is neutral GRF Ant. to hip, drives the hip into flexion Ant. to knee drives the knee into extension Ankle into plantar flexion Hip: hamstrings, gluteus maximus, and adductor magnus (i to e) Knee: quadriceps (c to e) Tibiotalar joint: tibialis anterior (e) Subtalar joint: anterior and lateral compartment muscles (e) 52
  53. 53. Sagittal Plane Analysis Loading Response Hip extension 25° Knee flexion to 20° Ankle plantar flexion to 10° Contralateral pelvis rotates anterior GRF Ant. to hip posterior to knee posterior to ankle Hip : extensors (e), Abductors (e) limit contralateral drop to 5° Knee : Quadriceps fire (c) Ankle :Tibialis anterior (e) 53
  54. 54. Sagittal Plane Analysis Mid Stance GRF through hip, knee, and ankle Muscular activity terminates Hip and knee stability provided by ligamentous restraints GRF Posterior to hip Anterior to knee and ankle Gastrosoleus complex fires to initiate knee flexion Pelvis continues to rotate, abductors continue to resist pelvic drop 54
  55. 55. Sagittal Plane Analysis Terminal Stance No change in GRF Free forward fall Strong activation of gastrosoleus complex 55
  56. 56. Sagittal Plane Analysis Pre-Swing Hip 20° of hyperextansion Knee 30° of flexion Ankle 20° of plantarflexion Toes 50° of hyper extension GRF posterior to hip, knee anterior to ankle Rapid flexion of knee from rapid heel rise and unweighting of limb Rectus femoris initiates hip flexion Adductor longus fires Hip : iliopsoas, adductor magnus, adductor longus Knee : Quadriceps Ankle :Gastrosoleus complex Toes : Ab.hal., FDB, FHB, Introssei, lumb. 56
  57. 57. Sagittal Plane Analysis Initial Swing Hip 0-30° of flexion Knee from 30-60° of flexion and extension from 60-30° Ankle 20° of plantarflexion to neutral Foot clearance is passive due to rapid hip flexion, unless gait is very slow In slow gait, tibialis anterior and hamstrings fire to help Gait cadence (speed) governed by accelerations of hip flexion during this phase Hip flexion Rectus femoris Iliacus Adductor longus Gracilis Sartorius Rest of limb is passive pendulum 57
  58. 58. Sagittal Plane Analysis Mid Swing Tibialis anterior fires to maintain foot position Knee extension and hip flexion continue by inertia 58
  59. 59. Sagittal Plane Analysis Terminal Swing Decelerate knee extension and hip flexion Hamstrings Gluteus max Quads co-contract Tibialis anterior maintains ankle position 59
  60. 60. Frontal Plane Analysis IC to LR Pelvis : forward rotn. Hip : med. rotn. of femur Knee : increased valgus Ankle : increased pronation Thorax : Post. postion at initial contact and begins moving forward Shoulder : extended and moving forward Gracilis, vastus medialis, semitendinosus, LH of biceps femoris Tibialis post. to control valgus thrust 60
  61. 61. Frontal Plane Analysis LR to Mid-stance Pelvis : Rt. side rotating backward to reach neutral. Lat. tilt towards the swinging extremity Hip : Med. rotn. of femur continues to neutral. Knee : Reduction in valgus and tibia begins to rotate laterally Ankle-foot : neutral at mid- stance Thorax : Rt. side move forward Shoulder : Move forward Hip abductors are active Tibialis post. produce supination 61
  62. 62. Frontal Plane Analysis Mid-stance to TS Pelvis : Rt. side move Posteriorly Hip : Lat. rotn. of femur and adduction Knee : lat. rotn. of tibia Ankle & foot : supination of subtalar jt. increases Thorax : Rt. side move forward Shoulder : Rt. shoulder move forward Hip : inconsistent adductor activity Ankle plantar flexor activity 62
  63. 63. Frontal Plane Analysis TS to PS Pelvis : Lt. side move forward, lat. tilting to swing side ends as double support begins Hip : Abduction as wt. shifted to opp. extremity, Lat. rotn. of femur Knee : Lat rotn. of tibia Foot/Ankle : Wt. shifted to toes. Supination of sub talar joint Thorax : Translation to the left Shoulder : Moving forward Hip adductors control pelvis Plantar flexion 63
  64. 64. Frontal Plane Analysis IS to MS Pelvis : Lat. pelvic tilt to the rt. Right side move forward Hip : Lat. rotn to med. rotn. Knee : From lat. to med. rotn Foot/Ankle : NWBing subtalar joint returns to supination Thorax : Rt. side move Posteriorly Shoulder : Rt. side move Posteriorly Left gluteus medius on pelvis 64
  65. 65. Frontal Plane Analysis MS to TS Pelvis : Rt. side move anteriorly Hip : Lat. tilting to the left med. rotn. Knee : Med. rotn. Ankle/Foot : Thorax : Rt. side move posteriorly Shoulder : Rt. shoulder move posteriorly Right gluteus medius 65
  66. 66. A word on running Walking is biomechanically like a pendulum, KE to PE to KE Running is biomechanically like a spring No double leg stance phase Aerial phase or float period Ground Reaction Force during stance phase loads spring (quads, achilles) Unloading in preparation for aerial phase is passive recoil from tendons and connective tissue and dynamic concentric muscular contraction 66
  67. 67. Running: swing phase Muscular rather than pendular motion at hip. Knee flexion, and ankle dorsiflexion, bring CoM of the leg closer to the hip. This reduces moment of inertia and increases angular velocity. Knee movements largely passive (i.e not due to muscle activity), and result from transfer of momentum from thigh. Depending on the speed of running, initial ground contact may be with heel, whole foot, or ball of foot. 67
  68. 68. Running: support phase Hip: slight flexion followed by extension. Gluteus maximus activity initially eccentric Knee: degree of flexion increases with speed; that of extension decreases. Quadriceps active at knee, initially eccentrically Ankle : dorsiflexion followed by plantarflexion. Gastrocnemius and soleus active during whole phase, particularly so at the end. Stretch shortening/energy storage activity occurs at all three joints 68
  69. 69. STAIR GAIT Stair Ascent Stance Phase 1. Weight acceptance 2. Pull up 3. Forward continuance Swing Phase 1. Foot clearance 2. Foot Placement Ascending stairs involves a large amount of positive work that is accomplished by concentric action of the rectus femoris, vastus lateralis, soleus and medial gastrocnemeus 69
  70. 70. STAIR GAIT Stair Descending Swing Phase 1. Foot clearance 2. Foot Placement Stance Phase 1. Weight acceptance 2. Pull up 3. Forward continuance Descending stairs is achieved mostly through eccentric activity of same muscles and involves energy absorption The support moments exhibit similar pattern in stair and level gait But magnitude is greater in stair gait 70
  71. 71. Sagittal Plane analysis of Stair gait WA to PU Hip : Extension from 60- 30° of flexion Knee : Extension from 80-35° of flexion Ankle : DF 20-25° of DF, PF 25-15° of DF Hip : Gluteus maximus, Semitendinosus, Gluteus medius Knee : Vastus Lateralis, Rectus femoris Ankle : Tibialis anterior, soleus, gastronemius 71
  72. 72. Sagittal Plane analysis of Stair gait PU to FC Hip : extension 30 - 5° of flexion, flexion 5-20° of flexion Knee : Extension 35-10° of flexion, flexion 5- 10° of flexion Ankle : PF 15°of DF to 15-10° of PF Hip : Gluteus maximus, gluteus medius, semitendinosus Knee : Vastus lateralis, rectus femoris Ankle : Soleus, gastronemius, tibialis anterior 72
  73. 73. Sagittal Plane analysis of Stair gait Foot clearance through foot placement Hip : flexion 10-20° to 40- 60° of flexion, extension 40- 60° of flexion to 50° of flexion Knee : Flexion 10° of flexion to 90-100° of flexion, extension 90-100° of flexion to 85° of flexion Ankle : DF 10° of PF to 20° of DF Hip : Gluteus medius Knee : semitendinosus, vastus lateralis, rectus femoris Ankle : Tibialis anterior 73
  74. 74. FACTORS INFLUENCING GAIT Age Gender Assistive devices abnormalities 74
  75. 75. FACTORS INFLUENCING GAIT Age A toddler has a higher COG, wider BOS, decreased single leg support time, a shorter step length , a slower velocity and a higher cadence in comparison to adult 3-5 year old showed increase in stride length adjusted to leg length, step length and a faster speed in gait From 6-13 years ROM of L/E were almost identical to adults. However linear displacement, velocities and accelerations are larger. Elderly demonstrate a decrease in natural walking speed, shorter stride and step length, longer duration of double support periods and smaller swing to support phase ratios 75
  76. 76. FACTORS INFLUENCING GAIT Gender Men Women Joint angle increases as speed increases Gait speed faster i.e.. 118-134 cm/s Step length larger Not much joint angle increase as compared to men Gait speed slower i.e.. 110-129 cm/s Step length smaller Increased hip flexion and decreased knee extension during gait initiation Increased knee flexion in pre- swing Increased stride length Greater cadence 76
  77. 77. FACTORS INFLUENCING GAIT Assistive devices Canes are typically been used on the contralateral side to an affected limb to reduce forces acting at the affected limb Use of cane on the contralateral side increase the BOS and decrease muscle, GRF forces acting at the affected hip and hip abductor & gluteus maximus activity was reduced to 45% Walker gait 77
  78. 78. COMMON GAIT ABNORMALITIES A. Deformity(Contracture) B. Muscle Weakness C. Sensory Loss D. Pain E. Impaired Motor Control(Spasticity) 78
  79. 79. Ankle and Foot Gait Deviation 79
  80. 80. Knee Abnormal Gait 80
  81. 81. Knee Abnormal Gait 81
  82. 82. Knee Abnormal Gait 82
  83. 83. Knee Abnormal Gait 83
  84. 84. Hip Abnormal Gait 84
  85. 85. Hip Abnormal Gait 85
  86. 86. Pelvis and Trunk Pathological Gait 86
  87. 87. Pelvis and Trunk Pathological Gait 87
  88. 88. Pelvis and Trunk Pathological Gait 88
  89. 89. Pelvis and Trunk Pathological Gait 89
  90. 90. COMMON TYPES OF ABNORMAL GAITS Scissor gait Antalgic gait Cerebellar ataxia Festinating gait Pigeon gait Propulsive gait Steppage gait Stomping gait Spastic gait Myopathic gait Magnetic gait Trendelenburg gait 90
  91. 91. Scissor gait Hypertonia in the legs, hips and pelvis means these areas become flexed, to various degrees, giving the appearance of crouching, while tight adductors produce extreme adduction, presented by knees and thighs hitting or crossing in a scissors- like movement, while the opposing muscles, the abductors, become comparatively weak from lack of use. Most common in patients with spastic cerebral palsy, usually diplegic and paraplegic varieties. The individual is forced to walk on tiptoe unless the dorsiflexor muscles are released by an orthaepedic surgical procedure. 91
  92. 92. Antalgic gait Person tries to avoid pain associated with the ambulation. Often quick, short and soft foot steps. 92
  93. 93. Ataxic gait Spinal - proprioceptive pathways of the spine or brainstem are interrupted. There is loss of position and motion sense. The person will walk with a wide base of gait with foot slap at heel contact. Often watch feet as they walk. Cerebellar - coordinating functions of the cerebella are interfered with, so the person tends to walk with a wide base of gait with an unsteady irregular gait, even if watching feet. 93
  94. 94. Festinating gait The patient has difficulty starting, but also has difficulty stopping after starting. This is due to muscle hypertonicity. The patient moves with short, jerky steps. 94
  95. 95. Pigeon gait In-toe gait is a very common problem among children and even adults. Fortunately, most in- toeing that is seen in children is a growth and developmental condition and will correct itself without medical or surgical intervention. 95
  96. 96. Propulsive gait Disturbance of gait typical of Parkinsonism in which, during walking, steps become faster and faster with progressively shorter steps that pass from a walking to a running pace and may precipitate falling forward. 96
  97. 97. Steppage gait A manner of walking in which the advancing foot is lifted high so that the toes clear the ground. Steppage gait is a sign of foot-drop. 97
  98. 98. Stomping gait Sensory ataxia presents with an unsteady "stomping" gait with heavy heel strikes, as well as postural instability that is characteristically worsened when the lack of proprioceptive input cannot be compensated by visual input, such as in poorly lit environments. 98
  99. 99. Spastic gait An unbalanced muscle action of certain muscle groups leads to deformity. Prime example is "Scissor gait" - adduction and internal rotation of the hips with an equinus of the feet and flexion of the knee. the legs are held together and move in a stiff manner, the toes seeming to drag and catch. 99
  100. 100. Myopathic 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. exaggerated alternation of lateral trunk movements with an exaggerated elevation of the hip. 100
  101. 101. Magnetic gait Normal pressure hydrocephalus (NPH) gait disturbance is often characterized as a "magnetic gait," in which feet appear to be stuck to the walking surface until wrested upward and forward at each step. The gait may mimic a Parkinsonian gait, with short shuffling steps and stooped, forward-leaning posture, but there is no rigidity or tremor. A broad-based gait may be employed by the patient in order to compensate for the ataxia. 101
  102. 102. Trendelenburg gait 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. To compensate, the trunk lurches to the weakened side to attempt to maintain a level pelvis throughout the gait cycle. The pelvis sags on the opposite side of the lesioned superior gluteal nerve. 102
  103. 103. Hemiplegic Gait Demonstration The patient has unilateral weakness and spasticity with the upper extremity held in flexion and the lower extremity in extension. The foot is in extension so the leg is "too long" therefore, the patient will have to circumduct or swing the leg around to step forward. This type of gait is seen with a UMN lesion. This girl has a right hemiparesis. Note how she holds her right upper extremity flexed at the elbow and the hand with the thumb tucked under the closed fingers (this is "cortical fisting"). There is circumduction of the right lower extremity. 103
  104. 104. Diplegic Gait Demonstration The patient has spasticity in the lower extremities greater than the upper extremities. The hips and knees are flexed and adducted with the ankles extended and internally rotated. When the patient walks both lower extremities are circumducted and the upper extremities are held in a mid or low guard position. This type of gait is usually seen with bilateral periventricular lesions. The legs are more affected than the arms because the corticospinal tract axons that are going to the legs are closest to the ventricles. This man has an UMN lesion affecting both lower extremities. He has spasticity and weakness of the legs and uses a walker to steady himself. There is bilateral circumduction of the lower extremities. 104
  105. 105. Neuropathic Gait Demonstration This type of gait is most often seen in peripheral nerve disease where the distal lower extremity is most affected. Because the foot dorsiflexors are weak, the patient has a high stepping gait in an attempt to avoid dragging the toe on the ground. This girl has weakness of the distal right lower extremity so she can't dorsiflex her foot. In order to walk she has to lift her right leg higher then the left to clear the foot and avoid dragging her toes on the ground. 105
  106. 106. Myopathic Gait Demonstration With muscular diseases, the proximal pelvic girdle muscles are usually the most weak. Because of this the patient will not be able to stabilize the pelvis as they lift their leg to step forward, so the pelvis will tilt toward the non-weight bearing leg which results in a waddle type of gait. This young boy has pelvic girdle weakness, which produces a waddling type of gait. Note the lumbar hyperlordosis with the shoulders thrust backwards and the abdomen being protuberant. This posture places the center of gravity behind the hips so the patient doesn't fall forward because of weak back and hip extensors. 106
  107. 107. Parkinsonian Gait Demonstration This type of gait is seen with rigidity and hypokinesia from basal ganglia disease. The patient's posture is stooped forward. Gait initiation is slow and steps are small and shuffling; turning is en bloc like a statue. This man's gait is bradykinetic and his steps are smaller then usual. There is also the pill-rolling tremor in his hands. He turns en bloc and there is decreased facial expression 107
  108. 108. Choreiform Gait Demonstration This is a hyperkinetic gait seen with certain types of basal ganglia disorders. There is intrusion of irregular, jerky, involuntary movements in both the upper and lower extremities. Note the involuntary, irregular, jerky movements of this woman's body and extremities, especially on the right side. There are also choreiform movements of the face. A lot of her movements have a writhing, snake-like quality to them, which could be called choreoathetoisis. 108
  109. 109. Ataxic Gait Demonstration The patient's gait is wide- based with truncal instability and irregular lurching steps which results in lateral veering and if severe, falling. This type of gait is seen in midline cerebellar disease. It can also be seen with severe lose of proprioception (sensory ataxia) This woman's gait is wide- based and unsteady. She has to use a walker or hold on to someone in order to maintain her balance (note how hard she has to work with the hand that she's holding on with in order to maintain her balance). Her ataxia is even more apparent when she tries to turn. 109
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