KINSIOLOGY
(SPSC-4537)
Ephrem Tamrat (PhD)
Introduction
Kinesiology is a combination of the Greek for 'to move'
(kinein) and 'logos' (discourse).
Aristotle (384-322 B.C.) is the “Father of Kinesiolgy”.

PARTS OF ANIMALS, MOVEMENT OF ANIMALS, and
PROGRESSION OF ANIMALS, described the actions of the
muscles and subjected them to geometric analysis for the first
time.
Cont..
• He first to analyzed and described walking, in which rotatory
motion is transformed into translatory motion.
• Archimedes
(287-212 B.C.), another Greek, determined
hydrostatic principles governing floating bodies that are still
accepted as swimming.
• Heath (1972) suggests that his inquiries included the laws of
leverage and determining the center of gravity
Cont...
Galen (131-201 A.D.) a Roman citizen who is the first team
physician in history.

He used number to describe muscles. He distinguished between motor
and sensory nerves, agonist and antagonist muscles, described tonus,
and introduced terms such as diarthrosis and synarthrosis.
Snook (1978) suggested that some writers consider his
discourse the first textbook on kinesiology, and he has been
termed "the father of sports medicine.“
KINESIOLOGY
Kinesiology is the study of human motion and mainly focuses on
muscles and their functions.
Biomechanics is the study of movement involved in strength
exercise or in the execution of a sport skill.
Biomechanics focuses on the physical factors with movement by
applying scientific laws.
Biomechanics explains the “why” of a movement and “how” the
movement can be improved through science-based modifications.
Cont…
 Biomechanics is the execution of doing an exercise
•
most effectively, while kinesiology tells which
muscles are involved in the particular actions.
THE CONCEPT OF KINESIOLOGY
Human movement primarily involves two
principles :•
BIOMECHANICS AND KINESIOLOGY.
•Biomechanics
is the study of motion and causes of motion of living
things, using a branch of physics known as mechanics.
•Kinesiology,
also known as human kinetic, is the scientific study of
human movement.
Cont…
Kinesiology addresses ;
 physiological,
 mechanical,
 psychological mechanisms, and
 includes the study of
 way of walking,
 posture and body alignment,
 ergonomics,
 sports,
 exercise movements, and
 activities of daily living (ADL).
Cont...
In order to understand these principles you must first gain
an understanding of;
 the anatomical position,
 planes of motion,
 center of gravity,
 line of gravity,
 Postural alignment and
 joint movement.
Therefore, study of human movement is the focus
of kinesiology and biomechanics.
Cont…
Students of physical education and sport study
kinesiology in order to learn ;

how to improve performance by analyzing the movement of the
body and

applying the principles of movement to their work.
To perform with optimum ;



safety,
effectiveness, and
efficiency.
Cont…
Safety, effectiveness and efficiency then, are the aims in all of our
use of kinesiology for the analysis and modification of human
movement.
SELECTED TERMS RELATING TO HUMAN MOTION
Kinematics-is the spatial and temporal characteristics of human
movement.
• i.e. the direction of motion and the time involved in executing the
motion.
•
velocity, acceleration, angular velocity, angular acceleration, and linear and
angular motion.
Cont…
Kinetics is concerned with the forces that cause, modify, or
inhibit motion.
•mass, force, pressure, gravity, friction, work, power, energy,
and torque.
MECHANICAL PRINCIPLES AND CONCEPTS
RELATED TO MOVEMENT
•Movements
principles.
are
governed
by
mechanical
• kinesiologists and biomechanists use
principles in the analysis of movement.
•Some of mechanical principles are
stability,
motion,
leverage, and
force.
these
STABILITY
 It is related to equilibrium and balance.
 When
all
the
forces
acting
on
the
body
are
counterbalanced by equal and opposite forces so that the
sum of the forces equals zero, equilibrium is maintained.
Stability is the body’s ability to return to a position of
equilibrium after it has been displaced.
The greater the body’ stability, the more difficult it is to
affect its equilibrium.
Cont…
Static equilibrium is when the center of gravity is in a
stable position (e.g. when one is sitting or performing a
handstand in gymnastics).
Dynamic equilibrium is a state in which the center of
gravity is in motion (e.g. when one is running or
performing a cartwheel in gymnastics).
In sport and movement terminology, stability is often
referred to as balance.
Cont...
The body’s ability to maintain stability or balance is
governed by three primary principles.
1. The lower the center of gravity to the base of support, is
the greater the stability.
2. The nearer the center of gravity to center of the base of
support, is the more stable the body.
•
Keeping the bodies weight centered over the base of support helps promote
stability. Example in starting a sprint race, the runners will lean forward to get out
of the starting blocks quickly.
3. Stability can be increased by widening the base of support.
•
To increase stability in situations where receiving or applying force, and the direction of the
force must be considered.
MOTION
Motion implies movement, which consists of destroying
or upsetting the equilibrium of the body.
A force is required to;





start a body in motion,
slow it down,
to stop it,
to change the direction of motion, or
to make it move faster.
Everything that moves is governed by the laws of motion
formulated by sir Isaac Newton.
Newton’s law of motion
1. Newton’s first law
The law of inertia


states that a body at rest will remains at rest and a body in
motion will remains in motion at the same speed and in the
same direction unless acted on by some outside force.
If the applied force is less than the resistance offered by the
object, motion will not occur.
CONCEPTS
Once an object is in motion it will take large force to maintain its speed and
direction
The heavier the object and the faster it is moving, the more the force that is
required to overcome its moving inertia or to absorb its momentum.
Cont…
2. Newton’s second law
The law of acceleration

states that a change in velocity (acceleration) of an object is directly proportional
to the force producing it and inversely proportional to its mass.
CONCEPTS

The heavier the object, the more force needed to speed it up (+ve acceleration)
or slow down (-ve acceleration or deceleration).
3. Newton’s third law
The law of action and reaction states that for every action there is an
equal and opposite reaction.
CONCEPTS

Whenever one object moves, another object moves too and in the opposite
direction. When you push something, it pushes back; when you pull something,
it pulls back.
Cont…
There are two major classifications of movement patterns.
These are:
 linear or translator and
 angular or rotary.
LINEAR AND ROTARY MOTION

Motion is linear or rotary. The human body usually employs a
combination of both.

The rotary action of the legs to drive the body in a linear direction
is an example.
i. TRANSLATORY OR LINEAR
the object is translated as a whole from one
location to another.
It is commonly called linear motion and is further
rectilinear or curvilinear.

Rectilinear motion is the straight line progression of an
object as a whole with all its parts moving the same
distance in the same direction at a uniform rate speed.

Example :- a child on a sled
Curvilinear motion refers to all curved translator
movement, that is, the object moves in a curved
path way.
Cont...
Rotary motion is increased when the radius of rotation is
shortened.
Conversely, rotary motion is decreased when the radius of
the moving body is increased.
FACTORS MODIFING MOTION
 Motion is usually modified by a number of external
factors, such as




friction,
air resistance, and
water resistance.
Whether these factors are a help or a hindrance on the
circumstances and the nature of the motion.
Cont...
The same factors yet hinder another.
 For instance, friction is a great help to the runner because
maximum effort may be exerted without danger or slipping, yet
on the other hand, friction hinders the rolling of a ball
The motion of the segments of the body is also modified by
anatomical factors.
These include
 friction in the joints (minimized by synovial fluid),
 tension of antagonistic muscle,
 tension of ligaments and fasciae,
 anomalies of bone and joint structure,
 atmospheric pressure within the joint capsule,
 and the presence of interfering soft tissues.
Cont...
Except for the limitations due to fat or muscle bulks, these modifying
factors are classified as internal resistance.
LEVERAGE
Efficient body movement is made possible through a system of levers.
 A lever is a mechanical device used to produce a turning motion
about a fixed point, called an axis.
 A lever consists of: Fulcrum (the center of axis of rotation)
 Force arm (the distance from fulcrum to the point of
application of force )
 Weight or resistance arm (the distance from the fulcrum to the
weight on which the force is acting)
The bone of the body act as levers, joints as the fulcrums, and the
force to move the bone or lever about the joint or fulcrum is produced
by the contraction of the muscles.
Cont...
Levers are divided into three types called;

first order levers,

second order levers and

third order levers.
The type of lever depends on where the effort acts compared with the
load and the pivot.
Cont...
First order lever
Second order lever.
Third order lever.
Cont...
Levers enable one to gain a mechanical advantage by producing
either strength or speed.
First class lever may produce both strength and speed unless the
fulcrum is in the middle of the force and weight, which produces a
balanced condition.
Second class lever produce force and third class lever favor speed.
The movements of the body are produced mostly through third class
levers.
In third class levers, the point of application of the force (produced
by the muscles), is located between the fulcrum (the joints) and
resistance (the object to be moved)
Cont...
CONCEPTS
Levers are used to gain a mechanical advantage by either
producing speed or force.
Greater speed is produced by lengthening the resistance
arm, and greater force is produced by lengthening the force
arm.
BY;
Lengthening the resistance arm
Greater force
Lengthening the force arm
Greater speed
Key points
• The human body is made up of levers, and these work
together to create movement.
• There are three types of levers you need to understand:
•
•
•
1st class levers – Fulcrum in the middle
2nd class levers – Load in the middle
3rd class levers – Effort in the middle
Cont…
• Every lever is made up of three parts:
Fulcrum
• The fixed point or axis of the lever. This is where the lever
turns/pivots.
• Joints are fulcrums in the body
Load/Resistance
• The weight or ‘resistance’ that the lever is moving. E.g. Lifting a
weight when doing a bicep curl
Effort
• The force applied to move the load. It can also be referred to as
‘force’. In the body the effort is provided by the muscles contracting.
First class lever
• First class levers have the fulcrum in the middle.
Example in the body
-Triceps causing Extension at the
elbow. E.g. When throwing a ball
• Fulcrum = Elbow
• Effort = Tricep
• Load = Arm/ball
Second class levers have the load
in the middle.
- This means a large load can be
moved with relatively low effort.
Example in the body
- Gastrocnemius causing plantar
flexion at the ankle.
E.g. When taking off in high
jump/jumping to shoot in
basketball.
- Fulcrum = Ankle joint
Second class lever
Third class lever
Third class levers have the effort in the
middle.
- This means they can produce a large
range of movement with relatively low
effort.
Example in the body
- Bicep causing flexion at the elbow
E.g. Performing a bicep curl
- Fulcrum = Elbow joint
- Effort = Biceps
- Load = Arm/weight
Understanding mechanical advantage
• Mechanical advantage measures the efficiency of a lever (how easy it
is to lift the load).
Mechanical advantage = Effort arm ÷ Resistance arm
• The advantage depends on the distance between the effort and the
fulcrum (effort arm)
• compared with the distance between the load (resistance) and the
fulcrum (resistance arm).
Resistance arm = Distance between the Load and the fulcrum.
Effort arm = Distance between the effort and the fulcrum.
Cont…
Q. What is the mechanical advantage of the lever shown below?
Extend your knowledge…
What would happen if you
moved the fulcrum closer
to the load??
Cont…
Mechanical
advantage =
Effort arm ÷
Resistance arm
Mechanical
advantage =
60/300
Mechanical advantage = 0.2
What you need… A ruler, a pencil and a load/resistance (e.g. rubber).
Your task…
1. Create a 1st class lever using the pencil as the fulcrum and the rubber
as the load at one end of the ruler.
2. Investigate what happens when you change the effort arm and the
resistance arm by moving the fulcrum along the ruler. Does it become
easier/harder?
Mechanical advantage – Rule 1
• When the effort arm is shorter than it’s load arm it has a low
mechanical advantage.
• A short effort arm allows fast movement of the load over a large
range of movement.
• Third class levers always have a low mechanical advantage
E.g. Bicep curl, rowing
Effort arm
Resistance arm
Mechanical advantage – Rule 2
• When the effort arm is longer than it’s load arm it has a high
mechanical advantage.
• This means heavy loads can be lifted with little effort.
• Second class levers always have a high mechanical advantage
E.g. Standing on tip toes, or performing a press up.
FORCE
Force is the effect that one body has on another.
It is invisible, but it is always present when motion occurs.
It should be pointed out, however, that there can be force without
motion.
Example;
 push against a wall by a person.
 two arm wrestlers are pushing against each other with equal force
and their arms remain relatively motionless.
PRODUCTION OF FORCE
• Body force is produced by the action of muscles.
• The stronger the muscles, the more force the body is capable of
producing.
Cont...
to realize the greatest force,
 the force of the muscle groups must be applied in the same
direction and in proper sequence.
for example, in the high jump the body should be lowered on the last
step before the jump.
This lowering of the body will enable the jumper to contract
the muscles of the thigh, which are the strongest of the body.
The upward movement of the arms will give added force to the
jump when coordinated with the upward push of the legs.
Force also must be generated to push objects. The same principles
apply as mentioned above.

Cont...
THE APPLICATION OF FORCE
The force of an object is most effective when it is applied in the
direction that the object is to travel.
To move the body upward, the body must be straight and all the force
must be directed upward through the center of the body.
The example of the high jump will illustrate this principle.
In throwing an object the following three main factors are of concern:



The speed of the throw
The distance of the throw and
The direction that the object will travel.
Cont…
The speed of the throw depends on the speed of the hand at the
moment of the release of the object.
The speed of the arm can be increased by

lengthening it to its fullest,

rotating the body,

shifting the weight properly, and

taking a step in the direction of the throw.
These movements must be done in a continuous motion to maintain
momentum.
MUSCULOSKELETAL
Skeletal muscles – work in pairs and are connected to the skeleton by
a tendon to help move limbs.
Muscle contractions – muscles can only contract to produce
movement. There are two types of muscle contraction.
A) Isotonic contraction
Isotonic contraction - are when Isometric contraction the muscle
changes length when it is under tension. The length of a muscle can
shorten or lengthen producing a concentric or eccentric contraction.
 Concentric contraction – this is the shortening of the muscle when
it is under tension (contracting).
 Eccentric contraction – this is the lengthening of the muscle when
it is under tension.
Cont...
B) Isometric contraction
•
Isometric contraction - is when the muscle stays the same length
when under tension.
Cont…
Example: An isotonic concentric is when you perform bicep curls as
part of a training session.
Example: An concentric contraction
during a bicep curl. This is when you
lift the weight and the bicep muscle
shortens (contracts).
Example: An eccentric concentric is
when you lower the weight during a
bicep curl and the bicep lengthens.
Cont…
Example: An isometric concentric
is, when performing bicep curls, if
you hold the movement half way.
The bicep holds the tension without
any shortening or lengthening of
the muscle.
Cont…
Isometric Contraction: In an isometric contraction there is strength
exhibited but no movement of the limb.
The muscle does develop tension and some contraction of the fibers
and tendons, but there is no movement.
Isometric contractions play a large roll in the stabilization in the joints
of our body.
An interesting fact about isometric contractions is that there is no
work being done.
Work is defined and measured by the formula
W = F x D.
W = work, F = force, and D = distance.
Cont...

Since in an isometric contraction there is no movement, there is no
work being done.
 For work to be done there must be movement.
 It is not to say that energy is not being used.
 Energy is more physiological, while work is more mechanical.
What roles do skeletal muscles play during movement?
• When completing movements such as walking or squatting, there are a
lot of different muscles involved in order to complete the movement
smoothly and effectively.
• They achieve this as they each adopted the appropriate type of
contraction (concentric, eccentric or isometric) and have their own
specific role that they play during the movement.
• There are four different roles that a muscle can fulfil during
movement, these roles are:
1. Agonist
2. Antagonist
3. Synergist
4. Stabilizers (Fixator)
Cont...
1. Agonist: is the muscle(s) that provides the major force to complete
the movement.
2. Antagonist: refers to the muscles that oppose the agonist.
• During elbow flexion where the bicep is the agonist, the triceps
muscle is the antagonist.
Cont..
3. Synergist: is the muscle(s) that stabilizes a joint around which
movement is occurring, which in turn helps the agonist function
effectively.
• Synergist muscles also help to create the movement. In the bicep curl
the synergist muscles are the brachioradialis and brachialis which
assist the biceps to create the movement and stabilize the elbow joint.
Cont…
Stabilizer (Fixator):
 stabilizer muscles aren't directly involved in moving the load, they
are working to keep certain body parts stable and steady so the
primary movers can perform the exercise efficiently, effectively,
and safely.
 Take bench press for example. Your rear deltoids are the main
stabilizer muscles during this exercise.
CHAPTER TWO: ANATOMY AND
KINESIOLOGY
BODY POSITION AND JOINT MOVEMENT
Anatomical Position
Cont…
Anatomical position is a universally accepted reference
position used to described regions and spatial relationships
of the human body and to refer to body positions.
DEFINITION OF TERMS
Anatomical position


most widely used & accurate for all aspects
of the body
standing in an upright posture, facing
straight ahead, feet parallel and close, &
palms facing forward
Fundamental position

is essentially same as anatomical position
except arms are at the sides & palms facing
the body
Anatomical Directional
Terminology
Inferior (infra)

below in relation to another structure; caudal
Superior (supra)

above in relation to another structure; higher,
cephalic
Distal

situated away from the center or midline of the
body, or away from the point of origin
Proximal

nearest the trunk or the point of origin
Lateral

on or to the side; outside, farther from the median
or midsagittal plane
Medial

relating to the middle or center; nearer to the medial
or midsagittal plane
Median

Relating to the middle or center; nearer to the
median or midsagittal plane
Anatomical directional terminology
1-57
Anatomical directional
terminology
Anterior

in front or in
the front part
Anteroinferior

in front &
below
Anterosuperior

in front &
above
• Posterior
– behind, in back, or in the
rear
• Posteroinferior
– behind & below; in back &
below
• Posterolateral
– behind & to one side,
specifically to the outside
1-58
Anatomical directional
terminology
Caudal

below in relation to another structure; inferior
Cephalic

above in relation to another structure; higher, superior
1-59
Anatomical directional
terminology
Deep

beneath or below the surface; used to describe relative
depth or location of muscles or tissue
Superficial

near the surface; used to describe relative depth or
location of muscles or tissue
1-60
Anatomical directional terminology
Prone

the body lying face downward; stomach lying
Supine

lying on the back; face upward position of the body
Anatomical directional
terminology
Dorsal

relating to the back; being or located near,
on, or toward the back, posterior part, or
upper surface of
Ventral

relating to the belly or abdomen, on or
toward the front, anterior part of
1-62
Anatomical directional
terminology
Volar

relating to palm of the hand or sole of the foot
Plantar

relating to the sole or undersurface of the foot
1-63
ANATOMICAL PLANES OF MOTION AND AXES
Imaginary two-dimensional surface through which a limb or body
segment is moved
Motion through a plane revolves around an axis
There is a ninety-degree relationship between a plane of motion & its
axis
Cont…
3 basic or traditional
in relation to the body, not in
relation to the earth
•Lateral or Sagittal Plane
•Anteroposterior or Frontal Plane
•Transverse or Horizontal Plane
Cont…
Lateral or Sagittal Plane

divides body into equal, bilateral
segments

It
bisects
body
into
2
equal
symmetrical halves or a right & left
half

Ex. Sit-up
Cont…
Anteropostirior or Frontal Plane

divides the body into (front) anterior &
(back) posterior halves

Ex. Jumping Jacks
Cont…
Transverse or Horizontal Plane

divides body into (top) superior & (bottom)
inferior halves when the individual is in
anatomic position

Ex. Spinal rotation to left or right
Axes
There are three main directions for axes in the body
that all movements rotate around. Each axis works
with a specific plane.



Frontal axis – line passing through the body horizontally
from left to right
Sagittal axis – line passing through the body horizontally
from front to back
Vertical (longitudinal) axis – line passing through the body
vertically from top to bottom
Actions
Plane
Axis
Movement
Sagittal
Frontal axis
Flexion and extension
Frontal
Sagittal axis
Abduction and adduction
Tranzverse
Vertical axis
Twisting/rotation
CENTER OF GRAVITY, LINE OF GRAVITY, AND
POSTURAL ALIGNMENT
The center of gravity (COG) is a theoretical point where the weight
force of the object can be considered to act.
It is the point where the three planes intersect.
It is the point of exact center where the body freely rotates, and the
body weight is equal on all sides.
When you are standing in a neutral position such as the anatomical
position your center of gravity is approximately at the second sacral
vertebra.
The COG changes as you move away from the anatomical position.
COG
Line of Gravity
The line of gravity (LOG) of the body is an imaginary vertical line
passing through the center of gravity.
 Understanding this line helps;
• identifying and correcting postural deviations
• improved body mechanics and
• reduced risk of injury.
Cont…
Impact of Incorrect Line of Gravity
a. discomfort
b. Fatigue and
c. chronic pain in joints