Physical Education Chapter 9 Kinesiology Biomechanics And Sports

Biomechanics is defined as the systematic study of the mechanics of body joints. According to Wikipedia, 'Biomechanics is the study of the structure and function of the biological system of humans.

A lever is a rigid bar which is capable of rotating about a fixed point called the fulcrum.

Equilibrium is defined as a state of balance or a stable situation, where opposite forces cancel each other out and where no changes are occurring.

There are two types of equilibrium. Dynamic equilibrium and static equilibrium.

Force can be defined as a push or pull by one body acting upon another. Force is a product of mass and acceleration of an object or person.

Center of gravity is that point in a body or system around which its mass or weight is evenly distributed or balanced and through which the force of gravity acts.

We lean forward while climbing up a hill to keep the center of gravity low to maintain stability.

Class III lever is used while we curl our biceps.

a. A fat person.
b. A girl standing in the stand at ease position.

Dynamic stability is balancing the body during movement. It frequently happens that the line of gravity of an athlete will fall outside the base of support for the movement. For example, in a sprint start, the body weight is ahead of the supporting foot but before the body can fall forward the other foot moves ahead to provide support and the process repeats itself. A man carrying the heavy bucket in his right-hand leans towards his left-hand side to maintain equilibrium. While climbing up a hill the climber bend forward so that he does not fall. The equilibrium is maintained by bringing the CG down.

A body is said to be in stable equilibrium if it comes back to its original position when it is slightly displaced.'Static stability is very important in shooting, archery and handstand in gymnastics, etc. Stable objects generally have wide bases and low CG. Bottom of the ship is made heavy to keep CG as low as possible. This makes the ship stable.

Followings are the example of a class I lever which is used by our body. Our skull is the lever arm and the neck muscles at the back of the skull provide the force (effort) to hit football while we lift our head up against the football (load). When the neck muscles relax, our head nods/hits forward.

Following is the example of class II lever which is used by our body. Our calf muscles and Achilles tendon provide the effort when the calf muscle contracts.The load is our body weight and is lifted by the effort (muscle contraction).

Resistance: Following is the example of class III lever which is used by our body. The biceps muscle provides the effort (force) and bends the forearm against the weight of the forearm and any weight that the hand might be holding.

A broad base of support: for greater stability increase the area of the base and lower the centre of gravity as much as is consistent with the activity involved.
Examples:

1. a basketball player stops, spreads his feet wide as shoulder line and lowers his CG to dodge the opponent.
2. Defence position of the player in volleyball.
3. The wide stance of a golfer.
4. Tackling the position of a player in football.

(ii) Stability is directly proportional to the weight of the body the object or a person with heavyweight will have greater stability as compared to the person with less weight. Example: it is difficult to move a heavier person as compared to a less heavy person. On the basis of this principle, wrestling, boxing, judo, etc. are organized according to different age groups.

(iii) The direction of an acting force: to start quickly in one direction, keep the-CG as high as possible and as near as possible to the edge of the base nearest to the direction of intended motion. Example: The crouched position in starting a race, the CG is kept high by not bending the knees extremely and by keeping the hips high, also the lean of the body is towards the hands so that the weight rests on the hands. From this position, the movement hands are raised from the ground; motion starts by reason of the pulling gravity. This pull is added to the force exerted against the starting block by the feet and thus aids in speed.

(iv) When the body is free in the air, if the head and feet move down, the hip move up and vice versa.
Example:

a. This principle is applied in the high jump in western or valley roll technique at the take of, the head and one foot is thrust up as high as possible. As the head and one leg clear the bar, they are dropped which raises the hips to clear the bar. As the hips are lowered, the opposite leg is raised to clear the bar.

b. This is also used in the pole vault, hurdles and jackknife, dive in swimming.

Centripetal force: this is the force that pushes or pulls an object towards the axis of rotation in order to make it follow a curve or circular pathway. When a player swings a bat, he applies centripetal force to make that bat follow the arc of swing. Centrifugal force: this is the force that pushes or pulls an object outward from the axis of rotation. This force is equal and opposite of the centripetal force. Centripetal and centrifugal force have innumerable application in sports like, Centripetal force is needed by the player to maintain his grip. If the rotational momentum is more, the centrifugal force could cause the player to lose his grip and the bat may go of the hand. These forces act when a runner takes a sharp bend leans inward to obtain the necessary centripetal force. A cyclist going around the curve leans towards the centre of the curve in order to get the necessary centripetal force.

1. Improves performance in sports: principles of biomechanics tell us about the right techniques, effective and result oriented posture to get more efficient results by applying a minimum muscular force which in turn improves performance in sports.
2. Improvement in technique: with the help of biomechanical principles the physical education teacher corrects the mistakes. This helps in improving the game and performance of the player.
3. Development of improved sports equipment: the principles of biomechanics are used to modify the sports equipment. For example, tee shirts, studs, spikes, swimming costumes, hockey sticks, different size footballs and low weight helmets for protection
4. Improve in the training techniques: a teacher can analyse the player's movement or action with the help of the biomechanical principles. It helps in improving the training techniques.
5. Prevents sports injuries: it helps to find out the factors or the forces that can lead to the injuries during the game situation. It also helps in prevention of the sports injury.
6. Helps in understanding the human body: it gives the knowledge of different systems of our body. For'example, nervous system, muscular system and skeletal system.
7. Knowledge of safety principles: biomechanics gives the understanding to analyse different movements that can harm the player. The teachers remove those unnecessary and harmful movements.
8. Helps in research work: biomechanics helps in teaching and learning process, ft also helps the teacher to acquire precision and accuracy of movement.
9. Creates confidence in player: The player knows that he is executing the movement scientifically with the help of principal of biomechanics. Thus the confidence of the player is enhanced.
10. Helps in maintaining a healthy body: Principals of biomechanics gives deep knowledge about the effect of physical forces and movements over the body as well as the movements which are safe and promotes health.
    Thus biomechanics helps in maintaining a healthy body.
11. Increases the popularity of sports: biomechanical principles have brought remarkable improvements in respect to technique, equipment, skill and playfields. It helps in promoting the games and sports in the masses.

1. By following the principles of kinesiology, the coach can guide his follow contestants to avoid sports injuries while performing.
2. Kinesiology helps the sports coach to get better results from their athletes and is usually helpful in the right performance of the sports skill and technique.
3. It enables the physical educators to reach right modes of physical activities to their pupils.
4. Physical educators that can impact various activities on the basis of knowledge of kinesiology.
5. Kinesiology helps physical educators and physicians in learning and correcting physical deformities of a person.
6. It enables the coach to provide effective scientific training of players.
7. Kinesiology plays an important role in the personality development of a sports person.
8. Kinesiology helps the sports coaches and trainers in the application of their relative methods of coaching efficiently and precisely.