CLASS 12 PHYSICAL EDUCATION CLASSES BY MAHENDRA RAJAK

1. PHYSICAL EDUCATION
CLASS – 12
MAHENDRA RAJAK
(TGT P&HE)
KV MAHABUBNAGAR
Biomechanics
and
Sports
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2. Key Points
 Meaning & Importance of Biomechanics
 Types of Movements (Flexion, Extension Abduction, Adduction)
 Axes and Planes
 Newton’s Laws of motion & its application in sports
 Projectile and Factors Affecting Projectile Trajectory
 Friction & Sports.
 Major Muscles Involved in Running, Jumping and Throwing
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3. Biomechanics
Bio - living organism
Mechanics - Branch of Physics. Which deals with effect of force on the object
Biomechanics is branch of Science which deals with effect of forces acting on a living of
organism in moving condition or in Stationary condition.
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4. Biomechanics helps in the field of sports
and Importance
 Improvement of Technique: Biomechanics helps to improve technique. It determines how the
technique should be execute to get best result. Example: Shifting from orthodox to disco put
Technique is shotput
 Improvement of Equipment: If helps to improve equipment According to nature & safety of the
game for example in increase in thickness of mat for high jump
 Improvement in Training method: It helps to develop new Training method to get better result.
for example, Development of Isotonic method to develop strength.
 Development of Skill: It helps to develop skill of the sports. Example: Development in the skill of
fielding in cricket.
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5. Types of Movements
Abduction:
It is that Movement in which
 moving body part move away from the midline of body
 It always occurs on frontal plane & sagittal axis.
Example: Moving of hand in sidewise direction i.e., hand going away from body.
Adduction:
It is that Movement in Which
 Moving part coming towards the midline of body
 It always occurs at frontal plane sagittal axis
Example : to back his hand to Attention position from the hands opening sides stage
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6. Types of Movements
Flexion:
It is that movement
 In which the joint on which the movement occurs. There will be decrease in the angle between the bone
of that joint
 It always occurs at sagittal plane & frontal axis
Example: Bending of Elbow and bending off knee
Extension:
It is that movement
 In which the angle between the bone of that joint on which movement is occurred will increase.
 It always occurs at sagittal plane & frontal axis
Example: Straighten of elbow from bending position, Straighten of knee from bending position in leg press
exercise ,In leg press exercise flexion of knee joint and extension of knee joint take place.
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7. Axis
Axis An axis is an imaginary line about which the body (or limb) rotates. It can be
divided in three parts
 Frontal Horizontal Axis Axis of the body that passes horizontally from side to side
at right angles to the sagittal plane.
 Vertical Axis Axis of the body that passes from head to foot at right angles to the
transverse plane.
 Sagittal Horizontal Axis Axis of the body that passes from front to rear lying at
right angles to the frontal plane.
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8. Plane
A plane is an imaginary flat surface along which a movement takes place. It can be
divided
in three parts
 Sagittal Plane A vertical plane of the body which passes from front to rear
dividing the body into two symmetrical halves.
 Transverse Plane Any horizontal plane of i the body which is parallel to the
diaphragm also called the’horizontal plane
 Frontal Plane Plane of the body which passes from side to side at right angles to .
The sagittal plane also called the coronal plane.
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9. Newton’s Laws of Motion
The three laws of motion were first compiled by Isaac Newton in his Philosophiæ Naturalis
Principia Mathematica (Mathematical Principles of Natural Philosophy), first published in
1687
 Newton's first law
 Newton's second law
 Newton's third law
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10. Newton’s First Law of Motion
 Newton’s First Law of Motion This law is also known as law of inertia. This law states that a body at rest
will remain at rest and a body in motion will remain in motion at the same speed and in the same direction
till any external force is applied on it to change that state.
Application of Laws of Motion in Sports
 Softball The ball is hit into the air. Eventually, gravity will act on the ball, pulling it down to the ground.
Then, it will roll until friction between the ball and the grass stops it.
 Soccer When a soccer ball is kicked into the air, gravity will pull it back to the ground. Then, it will
continue to roll until friction between the ball and the grass slows it down.
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11. Newton’s Second Law of Motion
 Newton’s Second Law of Motion This law states that the rate of change in acceleration of an
object is directly proportional to the force producing it and inversely proportional to its mass.
Application of Laws of Motion in Sports
 If a baseball player hits a ball with double the force, the rate at which the ball will accelerate (speed up)
will be doubled.
 Football players can slow down, stop or reverse the direction of other players depending upon how
much force they can generate and in which direction.
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12. Newton’s Third Law of Motion
 Newton’s Third Law of Motion This law states that to every action, there is always an equal
pad opposite reaction. This law . describes what happens to a body when it exerts a force on
another body. These three laws are still being used to this day to describe the kinds of objects
and speeds that we encounter in everyday life.
Application of Laws of Motion in Sports
 A swimmer propels herself through the water because the water offers enough counterforce to
oppose the action of her hands pushing, allowing her to move.
 An athlete can jump higher off a solid surface because it opposes his body with as much force as he is
able to generate, in contrast to sand or other unstable surface.
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13. Projectile
 A projectile has a single force that acts upon it-the force of gravity.
 If there were any other force acting upon an object then that object would not be a projectile.
 Projectile motion refers to the motion of an object projected into the air at an angle.
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14. Factors Affecting Projectile Trajectory
When the human body or an object is projected through space, three forces influence the course of flight
 Propelling Force The propelling force produces certain effects depending upon its point and direction of
application. If the application is directly through the projectile’s centre of gravity, only linear motion results
from the force. As the propelling force is moved farther from the center of gravity, rotatory motion of the
object increases at the expense of linear motion.
 Force of Gravity As soon as contact is broken with a projected object, the force of gravity begins to
diminish the upward velocity of the object. Finally, gravity overcomes the effects of the upward
component of the projectile and the object begins to descend.
 Effects of Air Resistance As the speed of an object increases, air resistance has a greater retarding effect.
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15. Friction
Friction is the force that combats relative motion between the two surfaces that comes in
contact. Friction always acts in the opposite direction of the applied force.
Type of frictions:
Static friction: The opposite force that comes into play when one body is actually not
moving over the surface of another body.
Dynamic friction are two types.
Rolling friction: The opposing force that comes into play when body is actually rolling
over the surface of another body. For example, hockey/cricket ball is hit.
Sliding Friction: The opposite force that comes into play when one body is actually
slide over the surface of other body for example sliding on the field of cricket by a fielder.
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16. Advantage of friction in the field of sports
 Keeps the object at position by friction, they can be placed at position and shaped.
 Helps to move: Frictional forces helps to move the object by friction. It helps in running, walking.
With friction of feet/ shoes on the surface, helps to speed. Frictional force helps to move the object in
the speed. For example: Spikes are used by the athletes to run fast.
 Hold or grip an object: with the help of friction the ridges of skin of our fingers and our palm used
to minimize friction.
 Produce heat: The law of conservation of energy states that the amount of energy remains constant.
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17. disadvantage of friction in the field of sports
 Wear and tear of object: Due to friction, there is wear objects and tear of objects. Lubrication is
used to allow the parts to move easier, moreover, prevents wear and tear.
 Wastage of Energy: Excess of friction means extra energy; thus, energy is being wasted.
 Slow down the Speed: In the roller Skating, Rolling Shoes and smooth surface are enable us to
grab and hold objects. For example– In badminton the players use grip to hold it.
 Makes movement difficult: Friction can make the job more difficult when one has to move the
object. Excess friction can make it difficult.
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18. Methods of Reducing Friction
 Polishing By polishing the surfaces in contact, they become smooth and the force of friction reduces.
Many implements like the discus are painted to reduce friction.
 Lubrication The lubrication of surfaces makes them slippery and this reduces the force of friction.
 Streamlining Friction due to air is reduced by streamlining the shape of the body. The airplanes are
made with a sharp front to reduce friction.
 Use of Ball Bearings Ball bearings are used to reduce the force of friction. Many sports require more
friction and other need lesser friction. In athletics, the shoes are designed to increase friction so that
better speed can be generated.
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19. Major Muscles Involved in Running
Running
 Running on a regular basis has many benefits, including weight loss, stress relief and maintaining a
strong and healthy body.
 As it is one of the more physically exerting activities, it can also cause damage to our body such as a
pulled hamstring or dislocation of our knee caps.
 With a little knowledge, we can help prevent these injuries with the right equipment and by properly
stretching our muscles before the run.
Primary muscles while running will include – your quads (quadriceps femoris),
hamstrings, gluteus maximus, iliopsoas, and your calf muscles.
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20. Major Muscles Involved in Jumping
 Only a small percentage of people has the natural ability to jump high.
 That is why it is important to train properly to improve your hops if you are not among that group.
 Part of this battle is knowing just what muscles are most important to lift your body off the ground.
 The stronger you make them, the more power you will have to jump high.
Primary muscles while Jumping will include – your quads (quadriceps femoris), hamstrings, gluteus
maximus, iliopsoas, and your calf muscles.
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21. Major Muscles Involved in Throwing
Throwing
Following are the muscles which are used while throwing any thing like ball, football etc. .
Primary muscles while Throwing will include – Shoulder Muscles, Triceps, Latissimus Dorsi,
Abdominals, Quadriceps
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22. Thanku
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