Bio-physical principles Apply to your skill

3 parameters that affect projectile motion Angle of release (and air resistance) –Determines SHAPE of trajectory –Parabolic trajectory neglecting air resistance Speed of release –Determines size of projectile’s trajectory –Combination of ANGLE and SPEED determine the projectile’s RANGE Projection height –Difference between height at release and height on landing –Increased projection height = increased flight time

FUNCTIONS OF LEVERS All levers have 2 functions: They either: 1.Increase the speed at which an object can move with a given effort. E.g. driver as opposed to an iron in golf 2.Increase the resistance that can be moved with a given effort E.g. Bench press – wide arms more force

Force summation To gain maximumpower, the force needs to be generated by: Using as many body parts as possible. In the correct sequence (use large muscles first & then the smallest muscles last but fastest). With the correct timing. Though the greatest range of motion.

Balance & Stability Line of Gravity Is the vertical line that passes through the centre of gravity to the ground Base of support Line of gravity Centre of gravity

Base of support Is the area within an object’s point of contact with the ground. The larger the area the base of support covers, the more stable an object will be. Base of support

Principles of Balance Balance is a desirable attribute in the performance of many skills. A body is most stable when the principles of balance are applied 1. Anything can be balanced if its centre of gravity is directly over its base of support 2. The wider the base of support the more balanced or stable the object or body is. 3. The lower the centre of gravity the more balanced or stable the object is. 4. As one body part moves another must move to compensate that movement

Mechanical Principle: Motion Newton’s First Law – Law of inertia Newton’s Second Law – Law of Acceleration Newton’s Third Law – Law of Action and Reaction

Newton’s 1st law of motion (law of inertia) A body will maintain a state of rest or constant velocity unless acted on by an external force. Implication: -Tackling in Rugby -Deflection of the ball in basketball -Weight training The inertia of an object is directly proportional to its mass. Therefore you need more force to alter the movement of a heavier object

A force applied to a body causes an acceleration of that body of a magnitude proportional to the force, in the direction of the force, and inversely proportional to the body’s mass. OR F = ma (extremely important!!!) Implication: Apply forces in direction of desired movement. - Kicking a soccer ball -tackling in rugby (again!) -Sprinting -Almost everything in life Newtons 2nd law of motion (law of acceleration)

For every action, there is an equal and opposite reaction Implication: Use reaction forces to your advantage Ground reaction forces in running Gravitational forces in weight training Catching a ball, forces of hands must be able to resist force of ball Swimming Newtons 3rd law of motion (law of reaction)

Mechanical Principle: Leverage Lever - mechanical device used to produce a turning motion around a fixed point called an axis. Lever components – Fulcrum - center or axis of rotation – Force arm - distance from the fulcrum to the point of application of the force – Resistance arm - distance from the fulcrum to the weight on which the force is acting