1. Motion Analysis Summer Course
Speaker: Yi-Jung Tsai
Date: 2011/07/13
Motion Analysis Laboratory

2. Outline Part I: Introduction of motion analysis Basic introduction
Research methods in motion analysis
Instrumentation
Data collection
Data analysis
Part II : Application
Gait analysis
Clinical application
Sports medicine

3. Part I: Introduction of motion analysis
Basic introduction
Research methods in motion analysis
Instrumentation
Data collection
Data analysis

4. Introduction What is motion analysis ?
When and why do we need to analyze motion?
What knowledge do we need before research?

5. Introduction Kinematics (運動學）
Kinematics is concerned with the geometry of motion and deal with relationships among displacement, velocity, acceleration, and time without any reference to the cause of motion
 To describe the motions we see
Kinematics: what we see

6. Introduction Kinetic (力動學)
Kinetics deal with relationships among forces, mass, and motion of the body, it is concerned with the cause of motion
 To understand why the motions occur
 force / torque

7. Introduction Anthropometry (人體測量學）
Involving body and limb measurements
mass of segment
location of mass center
segment length
center of rotation
angle of muscles
mass and cross-sectional area of muscles
moment of inertia
Important For kinetic

8. BM = Total Body Mass; BH = Body Height
Segment
   L (%BH)
Mass (%BM)
Child < 14 y Mass (kg)
%LCoM (%BH)  (from distal joint)
Child < 14y %LCoM (%BH) 
%I * (in kg.m2)
Head
9.6
7.8
*age 50
49.5
Torso
31.6
46.84
*age
*age
50.3
Upper arm
16.4
2.7
0.084*age+2.2
56.4
-0.028*age+55.7
32.2
Forearm
13.7
2.3
0.015*age+1.2 55
0.19*age+56.1
30.3
Hand
8.2
0.6
29.7
Thigh
25.4
9.9
0.364*age+6.634
56.7
*age
32.3
Shank
23.3
4.6
0.122*age+3.809 57
*age
30.2
Foot
11.7
1.4
0.015*age+1.87
*age
47.5
BM = Total Body Mass; BH = Body Height
I = %I*Segment Mass*Segment Length2

9. Introduction Muscle and joint biomechanics
Characteristics of muscle and joint
- length-tension relationship
- force-velocity relationship
- joint type

10. Introduction Electromyography (肌電圖）
- the study of muscle electrical activities
 providing information about the control and execution of voluntary movement

11. Steps of motion analysis
Setting the purpose
Choosing the appropriate instrumentation
Data collection
Data analysis
Results and interpretation

13. Instrument_ kinematics
（Electro) goniometers (量角器）
- a device for measuring joint angles

14. Instrument_ kinematics
Accelerometer (加速規）
- a device that measures acceleration
types:
strain gauge
piezoresistive
piezoelectric

15. Instrument_ kinematics
Imaging system
Cinematograph
digital video
charge-couple device (CCD) cameras:
- Motion analysis, VICON, Qualisys system

17. Eagle Digital RealTime System
Hz selectable frame rates
Passive (retroreflective) markers

18. EVa Real-Time Software (EVaRT)
3D Display
XYZ Graphs
Analog Graphs

19. Instrument_ kinetic Force transducers - measure the applied forces
types:
Piezoresistive
Piezoelectric

20. Instrumentation_ kinetic
Force plate
- most commonly used type of force transducer
- measuring ground reaction force (GRF)
type:
Strain gauge
Piezoelectric

21. Instrumentation_ kinetic
Kistler force plate

22. Instrumentation_ kinetic
Pressure sensor

23. Instrument_ EMG
Types:
- Surface EMG
- Wire EMG
- Needle EMG

24. Steps of motion analysis
Setting the purpose
Choosing the instrumentation
(kinematics, kinetic, EMG…..)
Data collection
Data analysis
Results and interpretation

25. Data collection
Calibration
- to define the global coordinate system

26. Data collection Preparation - measurements of basic data
- placement of EMG electrodes
- marker attachment on the landmark (marker set)
- others

27. Data collection Placement of EMG electrodes
Others: setting the appropriate mode
- sampling rate
- collection time
- amplify….

28. Steps of motion analysis
Setting the purpose
Choosing the instrumentation
(kinematics, kinetic, EMG…..)
Data collection
Data reduction & analysis
Results and interpretation

29. Data reduction & analysis
Signal output
Signal processing
- data smoothing
- interpolation
- filter:
low pass, band pass, high pass filter…...
- re-sampling
Setting the appropriate parameters

30. Planes of Motion:
1 = Frontal plane
2 = Sagittal plane
3 = Transverse plane

31. Data analysis Calculation - kinematics
Translation and Rotation of different coordinate systems
Resolve the joint angles:
Step 1: compute b
Step 2: compute a
Step 3: compute g

32. Data analysis Calculation kinetic(ground reaction force, joint moment)
Inverse dynamics
EMG:
Rectified
Linear envelope
Integrated……..

33. Take home message How to choose the appropriate instrument?
- according to the research purpose
- understanding the pros and cons
How to collect data well?
- following the manuscript
- setting the appropriate mode
What should be noticed in data analysis?
- avoid distortion after signal processing
- understanding the limitation and problems of different computing method
What should be noticed while reading the report?
- does the result make sense?

34. TAKE A BREAK

35. Part II : Applications Projects in motion analysis laboratory
Gait analysis
Clinical applications
Sports medicine

36. Gait analysis
Bipedal locomotion, or gait, is a functional task requiring complex interactions and coordination among most of the major joints of the body, particularly of the lower extremity.

37. Anatomical considerations_ hip joint
flexion-extension occurs about a mediolateral axis.
adduction-abduction occurs about an anteroposterior axis.
internal-external rotation occurs about a longitudinal axis.

38. Anatomical considerations_ knee joint
3 degrees of freedom of angular rotation are also possible during gait.
The primary motion is knee flexion-extension.
Knee internal-external rotation and adduction-abduction may also occur, but with less consistency and amplitude among healthy individuals owing to soft tissue and bony constraints to these motion.

39. Anatomical considerations_ ankle and foot
Ankle motion is restricted by the morphological constraints of the talocrural joint, which permits only plantarflexion (extension) and dorsiflexion (flexion).
In gait analysis as a rigid segment, the foot is required to act as both a semirigid structure and a rigid structure that permits adequate stability

40. Gait Cycle
Stance phase:60%, including foot flat, midstance, terminal stance, and pre-swing.
Swing phase: 40%, including initial swing, midswing, and terminal swing.

41. Time-distance variable
Ranges of normal values for time-distance parameters of adult gait at free walking velocity
Stride or cycle time
1.0 to 1.2 sec
Stride or cycle length
1.2 to 1.9 m
Step length
0.56 to 1.1 m
Step width
7.7 to 9.6 cm
cadence
90 to 140 step/min
velocity
0.9 to 1.8 m/sec

43. Clinical Applications
Musculoskeletal pathology
polio, muscle atrophy, amputation, osteoarthritis rheumatoid arthritis, trauma
muscle weakness, restricted joint mobility, pain
Upper motor neuron pathology
cerebral palsy, stroke, brain trauma
combine spasticity, sensory disturbance, error in control mechanisms

44. Chair-rise in Patients after Total Knee Arthroplasty
Fong-Chin Su, Kuo-An Lai, Wei-Hsien Hong
Clin Biomech 13: , 1998

45. Objectives
To understand the biomechanics and compensatory mechanisms of chair-rise in patients after TKA.
Functional evaluation of pre-op patients compared to the normal elderly.

46. Subjects * : (yr) (cm) (kg) normal elderly OA patient TKA patient 12
subject N age body height body weight
(yr) (cm) (kg)
normal elderly
OA patient
TKA patient 12
14*
12*
159.5 ± 6.9
154.5 ± 5.2
157.0 ± 5.7
61.0 ± 9.90
58.2 ± 10.5
73.3 ± 14.0
60.7±6.67
61.2 ± 7.60
64.8 ± 8.00
* :
OA patients ( 10 bilateral, 4 unilateral )
TKA patients ( 8 unilateral, 4 bilateral )

47. Experiment Setup
A/D
converter
computer
disk
storage
camera
interface

48. Marker Set

49. Sit-to-Stand a b c d a - b : flexion momentum phase * 4 chair heights:
b - c : momentum transfer phase
c - d : extension phase
* 4 chair heights:
115%, 100%, 80%, 65% knee height

50. Duration of the STS

51. COM displacement

52. Vertical velocity of COM

53. Angular changes_ hip joint

54. Angular changes_ knee joint

55. Joint flexion moment_ hip

56. Joint flexion moment_ knee

57. Joint flexion moment_ ankle

58. TKA patient
elderly
1.97 sec
1.81 sec
seat-off
41%
49%
59%
51%

59. elderly
TKA patient Fh Fk Fa

60. Joint Moment
COM
COM
elderly
TKA patient

61. Conclusion
TKA patient has larger displacement and horizontal velocity of COM compared to the normal elderly.
No significant difference in angles of three joints.
TKA patients has special pattern in nearly knee full extension.
TKA has larger ankle and hip moments. Increased chair height, decreased joint angles and moments.

62. Common Abnormal Kinetic Patterns of the Knee in Gait in Cerebral Palsy
C.J. Lin, L.Y. Guo, F.C. Su, Y.L. Chou
Gait & Posture, 11: , 2000

63. Objectives
To investigate the detailed kinetic characteristics of each abnormality.
23 children suffering from cerebral palsy with spastic diplegia, were recruited
46 limbs into four groups:
jump (n = 7)
crouch (n = 8)
recurvatum (n = 14)
mild (n = 17)

64. Crouch Gait
Results show that crouch gait usually has larger and long-lasting knee extensor moments at stance.
This reveals that rectus femoris has relatively high activation.

65. Knee flexor moments are large and long-lasting during stance.
 The biceps femoris muscle shows less activation in EMG
 the soft tissue behind the knee joint provides this flexor moment. This may result in worse recurvatum knee due to overstretch by the external forces.
Recurvatum Knee

66. Knee Angle FLEX EXT Recurvatum GAIT CYCLE % 20 40 60 80 100 10 30 5020 40 60 80
100 10 30 50 70
EXT
FLEX
Jump
Recurvatum
Crouch
Mild
Normal
(Degree)

67. Knee Joint Moment

68. Gait Analysis After Ankle Arthrodesis
W.L. Wu, F.C. Su, Y.M. Cheng, P.J. Huang, P.J. Chou, Y.L. Chou, C.K. Chou
Gait & Posture, 11:54-61, 2000

69. Aims
To employ a computerized motion analysis system to identify the effect of ankle arthrodesis on three-dimensional kinematic and kinetic behaviors of the rear and fore foot and muscle activities of the lower extremity during level walking.

70. Subjects Patients: 10 (7 males and 3 females)
with single-side solid arthrodesis of the ankle performed due to trauma, degenerative osteoarthritis or rheumatic arthritis, were recruited for this study.
The mean age was 39.6 years old (13 to 64 y/o).
The mean duration of follow-up after arthrodesis was 1.7 years (0.5 to 4 years).
Controls: 10 normal subjects, mean age 28.8 yrs (20 to 35 y/o)

71. Markers set & coordinate systemx f z h t y

72. Experiments

73. Spatiotemporal parameters

74. RANGE OF MOTION

75. Hindfoot Motion

76. Forefoot Motion

77. Ground Reaction Force Vertical Force Ankle arthrodesis Normal F3-T3
150
F3-T3
F1-T1
Vertical
Force
100
F2-T2
% BW 50
white: no change
red: increase
green: decrease 10 20 30 40 50 60 70 80 90
100
% Stance Phase

78. Ground Reaction Force Fore-aft force Ankle arthrodesis Normal F5-T520
% BW
F4-T4
F6-T6
-20 10 20 30 40 50 60 70 80 90
100
white: no change
red: increase
green: decrease
% Stance Phase

79. Ground Reaction Force Medial-lateral force Ankle arthrodesis Normal10 20 30 40 50 60 70 80 90
100
-10
% BW
% Stance Phase
F7-T7
F8-T8
F9-T9
white: no change
red: increase
green: decrease

80. Pressure distribution in stance phase1 2 3 4

81. 5 6 7 8 9 10

82. Conclusion - motion Hindfoot No 2nd rocker
Increased eversion and external rotation throughout whole gait cycle.
Forefoot
Increased third rocker motion at toe-off.
Increased adduction
Significant increased eversion at toe-off.

83. Rage of Motion Ankle fusion causes
decrease of sagittal movements of hindfoot.
increase of transverse movements of hindfoot.
increase of forefoot motion in three planes.

84. Ground Reaction Force Decreased loading rate.
Weak body support in midstance and push-off in preswing.
Smaller fore-aft shear force.
Greater lateral shear force.

85. Force and Pressure in 10 Masks
Affected side :
 pressure and force in rearfoot, forefoot and toe areas  lack of the force absorption and forward progression
 pressure and force in two midfoot areas  supposing pronated gait

86. Biomechanical Evaluation of New Type Stair Climbing Machine (S770)

87. Purpose
To investigate the biomechanics of new type stair climbing machine (S770).
(1) kinematics:
- movement range of hip, knee, and ankle joints
(2) kinetics:
- foot contact force
- joint moment
(3) muscle activities

88. Methods_ subject 12 healthy young adults - 2 females, 10 males
- Age: 24.5±1.2 y/o
- Body height: 171.1±5.5 cm
- Body weight: 64.0±9.6 kg

89. Methods_ instrumentation
6-axis load cell:
- embedded in the left foot pedal
Surface EMG system:
- MA 300
Motion analysis system:
- 8 Eagle digital cameras
- 15 reflective markers

90. Methods_ EMG Adductor Abductor Hamstring RF,VM,VL
Tibialis anterior and Peroneus longus
Gastrocnemius

92. Methods _ data collection
Four conditions:
- step to end range, trunk static
- step to end range, trunk shift
- step at selected range, trunk static
- step at selected range, trunk shift
Stepping at selected speeds
3 trials/condition, 15 secs/trial
* The resistance was consistent

93. Animation_ step to end range
Trunk static
Trunk shift

94. Animation_ trunk static
Step to end range
Step at selected range

95. Results_ joint angle PF(+) DF(-) Flex(+) Ext(-) Abd(+) Abd(+) Add(-)
Angular displacement change in a cycle.

96. Result_ foot contact force
Three directions of foot contact force in a cycle
Blue line (ML)  mediolateral direction
Green line (AP)  anteroposterior direction

97. Results_ foot contact force
Trunk shift > Trunk static
Trunk shift
End range
Trunk shift
Selected range
Trunk static
End range
Trunk static
Selected range
Stair climbing machine (S770) < walking and normal stair climbing ( > 1 BW)

98. Results_ joint moment
(+) abd

99. Results_ joint moment flex(+) flex(+) PF(+) ext(-) ext(-) DF(-)
Internal moment: is the same with muscle contraction.
Plot force and moment figure (CHANGE)

100. Results _ muscle activities

101. Results_ muscle activities

102. Thanks for your attention ~