Human gait involves a highly coordinated cyclic motion of the limbs to propel the body forward. The gait cycle consists of a stance phase where the foot is on the ground and a swing phase where it is off the ground. During stance, the body's center of mass falls forward to provide momentum for walking. Key muscle groups like the gastrocnemius help provide this forward propulsion. The central nervous system precisely controls muscles to maintain stability and balance during walking. Abnormalities can disrupt this coordination and cause deviations from normal gait patterns.

1. Basic Dynamics of
Human Motion (Gait
Analysis)
Prepared by: CPO Tumaini M
BME 304-Biomechanics
Bsc in Biomedical Engineering

2. GAIT-DEFINITION
 Word meaning is manner of
walking
 Highly controlled,coordinated
and repetitive series of limb
movements whose function is
to advance the body from
place to place with minimum
expenditure of energy

3. GAIT CYCLE
One gait cycle is the movement
of a single limb from heel strike
(initial contact ) to next heel
strike

4. SUBDIVISIONS OF GAIT CYCLE
 Stance phase and swing phase
 Stance phase begins with initial
contact of heel and ends with toe
off

5. SUBDIVISIONS OF GAIT CYCLE
 Initial contact occurs at 0% and 100% of gait
cycle and toe off occurs at 60%
 So stance phase is about 60% and swing phase
40% of gait cycle

6. STANCE PHASE
 Period when foot is on the ground
 Sub divisions
1) initial contact
2) loading response
3) mid stance
4) terminal stance and
5) pre swing

7. INITIAL CONTACT
 Occur at 0% of gait cycle
 Principal objective of body
is to position the foot
correctly as it comes in
contact with the floor
 Body is about to begin
deceleration

8. LOADING RESPONSE
 Occupies 0 to 10% of gait cycle
 Maintain smooth progression
while decelerating the body mass
as it travels from its zenith at
mid stance of opposite limb
 Opposite limb toe off occurs at
end of loading response . So this
is a period of double limb
support

9. MID STANCE
 Utilize momentum to maintain
stability of the hip and knee
while advancing the body over
a stationary foot
 The centre of gravity has
reached its zenith and forward
velocity is minimum
 Initial swing has begun on
opposite side

10. TERMINAL STANCE
 Occupies 30 to 50% range of
gait cycle
 Provide acceleration & to
ensure an adequate step
length
 Acceleration is provided by
1)forward fall of centre of
mass of body
2) concentric contraction of
triceps surae
Constitutes 80 -85% of total
energy generated

11. PRE SWING
 Occupies 50-60% range
of gait cycle
 Period of double limb
support
 Goal is to prepare the
limb for swing
 Initial contact of
opposite limb marks
beginning of pre swing

12. SWING PHASE
 Limb is off the ground
 Divided into
1) initial swing
2) mid swing
3) terminal swing

13. INITIAL SWING
 Occupies 60-70% range
of gait cycle
 Critical function is to
allow foot clearance &
variable cadence
 Varying cadence
requires CNS control &
precise timing of two
joint muscles

14. MID SWING
 Occupies 70 to 85% range of gait
cycle
 Critical function is to maintain
foot clearance

15. MID SWING (contd)
 Foot clearance depends
on maintaining a
relatively level pelvis,
sufficient hip flexion &
adequate ankle
dorsiflexion
 In normal gait foot
clearance is only 0.87cm

16. TERMINAL SWING
 Occupies 85-100%
range of gait cycle
 Function is deceleration
of shank & correct pre-
positioning of foot for
contact
 Complete knee
extension & neutral
position of foot are
critical for heel strike

17. Linear measurements- ( cadence
or temporal parameters )
 Step length
 Stride length
 Step time
 Cadence
 Walking velocity

18. KINEMATICS
 It denotes movements observed
and measured at the pelvis, hip,
knee, and ankle during stance
and swing phases
 It can be observed in 3 planes
sagittal
coronal
transverse

19. SAGITTAL PLANE
The pelvis tilts approximately 15 degree

20. SAGITTAL PLANE
HIP
• Stance –flexed at
initial contact
then extends fully
• Swing – hip flexes
rapidly to pull the
stance limb off
the ground

21. SAGITTAL PLANE
KNEE
• Stance- At initial contact
knee flexes 15 deg. It then
extends
• Swing – At heel rise knee
begins to flex again
reaching maximum flexion
in early swing .In
remainder of swing knee
extends passively

22. SAGITTAL PLANE
ANKLE
• Stance – neutral at initial
contact,then plantar flexes
5-10 deg as forefoot comes
to rest on the ground.-
FIRST ROCKER
• Ankle dorsiflexes throughout
mid stance as tibia moves
forward over plantigrade
foot – SECOND ROCKER

23. SAGITTAL PLANE
 ANKLE(CONTD)-during terminal
stance and pre swing
ankle plantar flexes and
heel rises to prepare for
push off- THIRD ROCKER
• Swing – dorsiflexion to
neutral position seen

24. CORONAL PLANE
 PELVIS-each hemipelvis
rises slightly during swing
phase
 - stance phase hemipelvis
drops slightly
 - accentuated pelvic drop in
swing seen in
trendelenburg gait

25. CORONAL PLANE (CONTD)
 HIP- Stance phase
– slight adduction
occurs
 - Swing – abduction
seen

26. TRANSVERSE PLANE
 Measure rotation
 Pelvis and hips rotate minimally
 Tibia has a fixed external rotation

27. NEUROLOGICAL CONTROL OF
GAIT
 Muscle actions programmed as
involuntary reflex arcs in EPS
 Golgi tendon ,muscle spindle &
joint receptors produce
neurologic feedback
 Voluntary modulation of gait
made by interaction with motor
cortex
 Cerebellum - balance

28. MUSCLE ACTIVITY
 Gait is maintained by gravity ,
momentum and muscle contraction.
Muscle contraction can be
• 1)Concentric
• 2)Eccentric
• 3)Isometric

29. MUSCLE ACTIVITY
CONCENTRIC CONTRACTION
 Muscle shortens
generating power
 Gastrocsoleus and
iliopsoas are the primary
accelerators of gait
 Concentric contraction of
these occur at terminal
stance

30. MUSCLE ACTIVITY
ECCENTRIC CONTRACTION
 Muscle lengthens despite
electrical contraction
 These slow down & stabilize joint
motions during gait
 Eccentric contractions
outnumber concentric
contractions during gait

31. ECCENTRIC CONTRACTION
 Eg:- tibialis anterior muscle
contracts eccentrically at
initial contact to slow down
plantar flexion of ankle
 -gastrosoleus contracts
eccentrically during 2nd
rocker to slow down
dorsiflexion

32. MUSCLE ACTIVITY
ISOMETRIC CONTRACTION
 No change in length of muscle
occurs
 Postural stabilisers like gluteus
medius work in this mode
 More muscle activity occurs in
stance phase
 In swing momentum carries the
leg forward

33. GAIT ENERGY AND EFFICIENCY
Prerequisites of
normal
ambulation are
 Stability at
stance
 Means of
progression
 Conservation of
energy

34. GAIT ENERGY AND EFFICIENCY
 Bipedal gait is inherently
unstable
and inefficient
 Quadrupeds run faster than
humans because vertebral and
trunk muscles act to augment
stride

35. GAIT ENERGY AND EFFICIENCY
PROGREESSION
• Forward fall of the
centre of gravity of
body from its high
point at mid stance
to its low point at
double support
• Now potential
energy is converted
to kinetic energy

36. GAIT ENERGY AND EFFICIENCY
PROGRESSION (contd)
 To raise the CG back to zenith
kinetic energy must be supplied
 This is supplied by inertia of
swinging limb which in turn
derives energy from plantar
flexors and hip flexors of that
limb

37. GAIT ENERGY AND EFFICIENCY
PROGRESSION (contd)
 In normal walking 85% of
energy comes from plantar
flexors
 Energy expended in normal
walking is 2.5 Kcal/min
 This is less than twice the energy
spent while standing still -
1.5Kcal/min

38. GAIT ENERGY AND EFFICIENCY
ENERGY CONSERVATION
Energy is conserved in 3 ways
• Minimizing the excursion of C of G
• Controlling momentum
• Active or passive transfer of energy
between segments

39. GAIT ENERGY AND EFFICIENCY
ENERGY CONSERVATION
 Movement of a wheel is highly
efficient as C of G remains constant
 By three planes of pelvic movement ,
rotation, tilt ,& obliquity combined
with coordinated knee and ankle
motion the vertical and horizontal
excursion are reduced to 4.4cm

40. GAIT ENERGY AND EFFICIENCY
ENERGY CONSERVATION
CONTROLLING MOMENTUM
*This conserves energy
eg:-by maintaining the
ground reaction force in front
of the knee during the last
half of stance , an extension
movement occurs which
allows it to remain stable

41. GAIT ENERGY AND EFFICIENCY
ENERGY CONSERVATION
ACTIVE OR PASSIVE TRANSFER OF ENERGY
• Passive flow of energy across joints
accounts for most of the energy
changes occuring at the distal
segments during initiation and
termination of swing
• In active transfer two joint muscles
play a major role

42. GAIT ENERGY AND EFFICIENCY
 Interference with these mechanisms
increase energy consumption
 Eg:-fast walking – 60% inc
BK brace - 10%
15 deg knee flexion contracture -25%
BK amputee – 60%
AK amputee – 100%
crutches - 300%

43. DEVELOPMENT OF GAIT IN
CHILDREN
 Toddlers walk with a wide based
gait, increased flexion of hip and
knees & arms held out to the
sides
 At 5 yrs child has developed a
stable velocity pattern
 Adult gait pattern is attained by
7 yrs

44. GAIT ANALYSIS
 Systematic description
and assessment of qualities that
characterize human locomotion
 Mainly used in pre operative
planning and documentation of
post operative outcome in
patients with cerebral palsy

45. GAIT DEVIATIONS
 Due to pain
 weak muscle
 abnormal muscle activity
 joint abnormalities
 Contractures around joints
 limb length discrepancies

46. GAIT DEVIATIONS
1)antalgic gait - dec stance phase
avoiding wt. Bearing on involved limb
2)Short limb gait – dipping of shoulder
and pelvis on affected side & inc
flexion of hip , knee and ankle of
opposite limb.
3)Trendelenburg gait –patient lurches
on affected side & pelvis drops on opp
side

47. Goddess trying to avoid
Short lomb gait

48. GAIT DEVIATIONS
4)Waddling gait – patient lurches
on both sides during walking
5)High stepping gait – patient
flexes foot and knee excessively
to clear the ground

49. GAIT DEVIATIONS
6)Scissoring gait – one leg
crosses directly over the other
with each step
7)Calcaneus gait –walks on
broadened heel with tendency to
external rotation and genu
recurvatum. No calcaneal pick up
and push off

50. GAIT DEVIATIONS
8)Stiff hip gait – no movements
at affected hip , excess
movements in spine & unaffected
hip
9)Stiff knee gait – no flexion at
knee, so pelvis raised during
swing

51. GAIT DEVIATIONS
10)Gluteus maximus gait –
patient lurches backwards due to
weak gluteus maximus
11)Gluteus medius gait – like
trendelenburg gait

52. GAIT DEVIATIONS
12)Quadriceps gait / hand to knee
gait – patient stabilizes hips &
knee for weight bearing by
leaning on affected side &
pressing over lower thigh by his
hand

53. CONCLUSION
 Normal gait is designed by God
Almighty to be efficient & all the
priorities are met . In abnormal
gait these are lost
 Studying the human gait has
enabled us to define , document
& analyze normal and abnormal
human gait more accurately

54. THANK YOU