國立台灣大學物理治療學系九十三學年度/ 肌動學
ESSENTIAL TOPICS OF HUMAN MOTION
課程目標： 修習本課後, 學生應可
1. 指出人體的動作平面、動作軸心、
2. 使用人體動作學的詞彙描述動作
3. 了解位移、速度、加速度間的相關性，及對動作的意義
4. 分辨直線運動與角動運動間的差別，及人體動作之歸屬
Readings:
1. Neumann, DA, 2002: pp.4-11
2. Luttgens & Hamilton 2002: Chap11
Orientation of the Body
A. Reference planes of the body
1. definition: to describe planes of human motion in the context of a person standing in the
anatomical position
location
bisecting the body into
sagittal plane (median plane)
vertically from front to back
right/ left
frontal plane (coronal plane)
vertically from side to side
anterior/ posterior
horizontal to the body
upper/ lower
transverse plane (horizontal plane)
2. cardinal plane: the plane where the center of mass (COM) passes through when an individual
stands in the anatomic position
B. Axes of rotation
1. definition: the pivot point for an angular motion, usually located through the convex member
of the joint
sagittal axis (anteroposterior axis)
frontal axis (transverse axis)
vertical axis
HC\Kines04\kMotion04.doc
direction
perpendicular to
horizontally from front to back
frontal plane
horizontally from side to side
sagittal plane
perpendicular to the ground
transverse plane
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國立台灣大學物理治療學系九十三學年度/ 肌動學
ESSENTIAL TOPICS OF HUMAN MOTION
2. Although the three orthogonal axes are depicted as stationary, in reality, each axis of all joints
in human body migrates throughout the range of motion because the articular surfaces of the
joint are not reciprocally shaped as a perfect sphere
3. longitudinal axis： axis that extends within and parallel to a long bone or body segment
Description of Human Motion
A. Description of body segments
1. upper extremity (arm): upper arm + forearm + hand
2. lower extremity (leg): thigh + low leg + foot
3. trunk: chest and upper back + abdomen and low back
4. head and neck
B. Description of motion direction
1. anterior vs. posterior
-- front vs. back
-- forward vs. backward
2. medial vs. lateral
-- left vs. right
-- toward vs. away
-- inward vs. outward
3. superior vs. inferior
-- upper vs. lower
-- cranial vs. caudal
-- top vs. bottom
-- proximal vs. distal
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國立台灣大學物理治療學系九十三學年度/ 肌動學
ESSENTIAL TOPICS OF HUMAN MOTION
C. Description of motion
1. kicking: the leg moves forward in the sagittal plane about a frontal axis
2. turning the head: the head moves around a vertical axis in the horizontal plane
3. diagonal movement: the movement occurs in a plane which is not parallel to any cardinal
planes, for example, ankle motions
Motions Occurring in the Body Plane
A. Movements in the sagittal plane about a frontal axis
1. flexion: the angle of a joint becomes smaller
2. extension: the angle of a joint becomes larger
3. hyperextension: extension goes beyond the anatomic reference position
4. dorsiflexion/ plantarflexion: used for ankle or foot movements
5. forward/ backward bending: used for trunk movements
6. nutation/ counternutation: used for sacroiliac movements
B. Movements in the frontal plane about a sagittal axis
1. abduction: the distal segment moves away from the midline of the body
2. adduction: the distal segment moves towards the midline of the body
3. exception: finger or toe movements
4. lateral flexion: used for neck or trunk movements
5. radial deviation/ ulnar deviation: used for wrist movements
6. inversion/ eversion: used for foot movements
C. Movements in the transverse plane about a vertical axis
1. external rotation (lateral rotation): the anterior surface of the distal segment moves outwards
2. internal rotation (medial rotation) : the anterior surface of the distal segment moves inwards
3. supination/ pronation: used for forearm or foot movements
4. abduction/ adduction: used for foot or toes movements
D. Nonaxial movements
movements in a plane joint, such as the facet joints of the spine
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國立台灣大學物理治療學系九十三學年度/ 肌動學
ESSENTIAL TOPICS OF HUMAN MOTION
E. Movements in a combination of planes
1. circumduction: the distal segment follows the surface of a cone and the tip of the segment
trace a circular path
2. finger opposition
F. Thumb movements
1. flexion/extension in the palmar plane
2. abduction/ adduction in a plane perpendicular to the palm
Types of Motion
A. Definition of motion
1. motion: the act or process of changing place or position with respect to some reference point
(Luttgens & Hamilton, 2002, p.284)
2. rest vs. motion: depending on the reference point
3. absolute motion vs. relative motion: depending on the reference system
4. Newton’s law
-- Law of Inertia
-- Law of Acceleration： F = ma
-- Law of Reaction
B. Classification based on path of motion
1. translatory motion (linear motion, translation): a motion that the object moves as a whole in a
straight path from one place to another
-- linear (rectilinear) motion: a straight-line progression of an object as a whole with all of its
parts moving the same distance in the same direction at a uniform rate of speed
-- curvilinear motion: a curved progression of an object
-- circular motion: a special form of curvilinear motion, which is the motion when a body
moves along a circumference of a circle
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國立台灣大學物理治療學系九十三學年度/ 肌動學
ESSENTIAL TOPICS OF HUMAN MOTION
2. rotary motion (angular motion, rotation): a motion
that the object moves in an arc about a fixed point
-- angular motion
-- spin
C. Classification based on repetition of motion
1. Single motion: movement performed only once
2. Repeated motion: same movement pattern that is
done many times in a given time
-- reciprocating motion
-- oscillation
-- pendulum motion
D. Classification based on degree of freedom
1. degree of freedom (DOF)： a minimum number of kinematic variables required to specified
all positions and orientations of the body segments in a body system i.e.
-- the number of planes in which the segments move
-- the number of the primary axes which the segments possess
2. The joint that moves in one plane possesses one axis and has one degree of freedom
3. For the glenohumeral joint, there are three angular degrees of freedom and three linear
degrees of freedom.
E. Classification based on relative segment kinematics
1. kinematic chain: a series of connected segment links
2. open kinematic chain motion: the joint motion with the distal
segment moves free in space, e.g. raising lower
leg or throwing a ball
3. closed kinematic chain motion: the
joint motion with the distal
segment is fixed, e.g. standing up
or squatting down
4. In Neumann's book,
"distal-on-proximal segment
kinematics" and
"proximal-on-distal segment kinematics" were used in stead of open and closed kinematic
chain motion, respectively (Neumann 2002, p.7).
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國立台灣大學物理治療學系九十三學年度/ 肌動學
ESSENTIAL TOPICS OF HUMAN MOTION
F. Classification based on presence of muscle contraction
1. active motion: the motion that is caused by muscle contraction
2. passive motion: the motion that is created by sources other than muscle, such as from gravity
G. Classification based on joint kinematics
1. osteokinematic movement： movements between 2 bony segments
2. arhtrokinematic movement： movements between 2 articular surfaces
Kinematic Description of Motion
A. Linear kinematics
1. displacement (d): the vector that indicate the distance and direction an object moves from the
reference point
-- amplitude  distance
-- direction
2. velocity (v): rate of change in displacement
-- amplitude  speed
-- direction
3. acceleration (a): rate of change in
velocity
4. relationship between displacement,
velocity, and acceleration
x = v0t + (1/2)at2
v = v0 + at
average velocity = (v0 + v) / 2
B. Angular kinematics
1. angular displacement:  + (1/2)  t2
2. angular velocity: = d  / dt =  0 +  t
3. angular acceleration:  = d / dt
4. linear and angular conversion for a angular motion
= d / r
=v/r
=a/r
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國立台灣大學物理治療學系九十三學年度/ 肌動學
ESSENTIAL TOPICS OF HUMAN MOTION
Factors That Modify Motion
A. Extrinsic factors
1. gravitation force
1 g = 9.81 m/s2 = 32 ft/s2
weight (W) = mg = 9.81 m
2. contact forces
a. normal reaction force
b. friction force
3. fluid force
a. buoyancy
b. drag
c. lift
B. Intrinsic factors
1. friction between articular surfaces
a. minimized by synovial fluid
b. Synovial membrane is affected in patients with rheumatoid arthritis (RA). Patients would
suffer from pain when the affected joints move.
c. tension of antagonistic muscles, ligaments, fasciae, and capsules
-- Antagonistic structures are tight in patients with joint contracture. The range of motion
decreases in that joint.
d. anomalies of bone and joint
e. atmospheric pressure within the joint capsule
f. presence of interfering muscle bulk or adipose tissues
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