Balance

Definition of terms

• Balance- is the ability to retain your centre of gravity over your base of support.

Two types:• Static- e.g. Gymnastics- headstand

• Dynamic- e.g. Skiing- when changing direction

• Centre of Gravity- isan invisible line that runs through the point at which your body is ‘most’ balanced.

• Body tension- is the ability of a muscle or a group of muscles to contract in order to hold/control the body in position.

Centre of Gravity

Effects on Performance

Improving skills/performance:• Having a ‘good’ level of balance is

important in all sports.• If you cannot hold your balance

whilst performing a skill, your technique will suffer.

• E.g. A volley in Football, a Drive in Golf.

Effects on Performance

Large/small base• Generally the larger surface area

your base of support covers the ‘more ‘ balanced you will be.

Body weight over base• Your centre of gravity must be over

your base of support to maintain your balance.

QuestionsQ1. State the definition for Balance?______________________________________________________________________________________________________________________________

Q2(a). What is the difference between a static and a dynamic balance?

______________________________________________________________________________________________________________________________________________________

Q2(b). Give an example of each, commenting how you controlled your movements to stay balanced?

________________________________________________________________________________________________________________________________________________________________________

Transfer of Weight

Definition

• Transfer of weight- is the ability of a force to be transferred through part or the whole body.

• E.g. Tennis serve- legs to racquet Golf Drive- back-foot to front

foot

Application Of Force

Definition

When performing different skills andtechniques different forces are appliedand resisted.

For every action there is an equal and opposite

reaction (Newton’s Third Law)

A footballer kicking the ball A shot putter ‘putting’ the shot

In both these examples, speed and power are important in applying

force. The direction of the force is also important.

In the football example the footballer is trying to keep the shot low

and close to the ground. For the shot putter there is an optimumangle at which to putt the shot.

Resisting Forces

Starting Blocks Studded Boots

Chalk Dust

To help performers resist the forces involved in completing differentactions various types of equipment are used. Sprinters use starting

blocks,outdoor games players use studded boots to provide grip and

resistance.By contrast, shot putters use chalk dust to reduce friction to makethe shot putt easier to throw.

Application of Force

Activity Skill/Technique Type of Action Application of Force

Benefit

Swimming Backstroke Starting As I push backwards against the wall, I am powerfully extending and straightening my legs.

This enables me to get into my swimming stroke quickly after my push off and glide are complete.

Basketball Rebounding

Jumping As I push down against the floor, I am powerfully extending and straightening my legs.

This enables me to jump high and secure possession of the ball.

Rotation

Definition

Rotation is the movement of the body (or

part of the body) around a central axis.

In different activities you rotate (turn) inorder to carry out effective skills andtechniques.

Rotation

• In different activities you rotate (turn) in order to carry out effective skills and techniques, eg

discus hammer

throw

gymnastics

RotationWhen throwing the discus in athletics you turnaround in a spinning back-to-front movement

togenerate power.

This is a complex technique. You build up speedbefore throwing by quickly turning your feetaround. After the throw you follow through andkeep turning until you have regained yourbalance.

Rotation

• As well as rotating around you also can rotate by turning head over heels.

Front Somersault

• The tighter the tuck the quicker you will rotate. Rotation is important when completing a front somersault in trampolining.

Rotation

• Another form of rotation is when you turn sideways.

cartwheel

A cartwheel – where you turn over from feetto hand, balancing on the ground beforereturning to feet on the ground – is an exampleof this type of rotation.

Mechanical Principles

Resistance

ResistanceWhen you apply a force there will be a resistance

Resistance can either be an advantage of

disadvantage.

Advantage

• When sprinting in athletics the starting blocks are an advantage.

• They provide a resistance, by powerfully straightening the legs against the starting blocks the sprinter can quickly gain speed.

Disadvantage

• The swimmer is having difficult in swimming effectively due to the resistance created by poor streamlining.

• The second swimmer the leg action is more effective, less water is displaced, the swimmer’s centre of gravity is higher.

• Overall, the forces applied are overcoming the resistance created by the water in a more effective way.

Mechanical Principles

Follow Through

Follow Through

A good follow through is part of effective performance and follows on from the preparation and action phases in different skills and techniques.

Kicking and Throwing

• In rugby the follow through is in the direction of the shot.

• In baseball the throwing action the arms follows the intended direction of the throw.

• In other actions the follow through involves body rotation. The ball and socket joints in the hips and shoulder help rotation in the two different striking actions in tennis and golf.

Effect of Follow Through on Performance

• When completing different skills and techniques it is important for effective performance that kicking, striking/hitting and throwing actions have a good follow through.

• An effective follow through follows the preparation and action phases in different skills and techniques.