You will learn the following Stability & Balance 1) centre of gravity 2) line of gravity 3) base of support Newton’s 3 laws of motion 1 st Law of Inertia 2 nd Law of Acceleration 3 rd Law of Action/reaction Force summation Levers Projectile motion

Stability & Balance

Maintaining stability and _________ during sporting situations/performance has a number of benefits. It allows a person to put more force into a movement and complete that movement ____________ and with control. Achieving balance and stability involves ______________ your centre of gravity, line of gravity and base of _________. Support Accurately Balance controlling Stability is defined as: The ability to hold or maintain a position in space

Answers Maintaining stability and balance during sporting situations/performance has a number of benefits. It allows a person to put more force into a movement and complete that movement accurately and with control. Achieving balance and stability involves controlling your centre of gravity, line of gravity and base of support.

Principle 1 the closer the line of gravity is to the centre of the base of support, the greater the probability of maintaining balance Principle 2 the broader the base of support, the greater the probability of maintaining balance Principle 3 the probability of maintaining balance increases when the COG is lowered in relation to the BOS Principle 4 the further one body part moves away form the line of gravity, the probability of maintaining balance decreases unless another body part moves to compensate for it.

Principles of stability and balance Principle 1 the closer the line of gravity is to the centre of the base of support, the greater the probability of maintaining balance Line of gravity

Principles of stability and balance Principle 2 the broader the base of support, the greater the probability of maintaining balance Base of support

Principles of stability and balance Principle 3 the probability of maintaining balance increases when the COG is lowered in relation to the BOS Bending his knees to be more balance

Principles of stability and balance Principle 4 the further one body part moves away form the line of gravity, the probability of maintaining balance decreases unless another body part moves to compensate for it.

Stability and Balance There are three concepts of stability and balance… 1) Centre of gravity (COG) 2) Line of gravity (LOG) 3) Base of support (BOS)

Centre of Gravity The point at which all parts of the body/object are equally balanced

Determining the Centre of Gravity Box Method Where you draw a box around the object and draw diagonal lines in the shape of an X inside the box, the point at which the two lines cross is the COG.

When we stand in the anatomical position, our COG is located around the hip region.

Line of Gravity Is the vertical line that passes through the centre of gravity to the ground. This line can fall outside of the body if it is on an angle.

Base of Support 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. The persons feet are normally their BOS.

BOS is the area within an objects point of contact with the ground. The larger the area the base of support covers, the more stable an object will be. Wide BOS Narrow BOS BOS Base of support – The object on the left is more stable because of its relatively larger BOS

The picture on the left has a ________Base of support and therefore is more balanced than the picture on the right. The picture on the right has a small _________________ as her feet are close together, which means she has less balance than the picture on the left.

Line of gravity Centre of gravity STABLE Centre of gravity UNSTABLE Line of gravity

Increasing stability and balance To increase the stability and balance of a person you can do the following things Widen the base of support by putting feet shoulder width apart and having as many body parts in contact with the ground at once. Lowering the centre of gravity by bending knees (to get closer to the ground)

What other factors can increase stability? 1) Increase friction with the playing surface eg- spikes or sprigs on boots 2) Lean into an oncoming force eg- leaning into an oncoming tackle in rugby or league 3) Increase rotation eg- you are more stable on a bike moving than one standing still 4) Increase mass eg- a larger person is harder to move because they have more inertia

REVISION

1)Which item on my foot with give me the biggest Base of Support (BOS) and Why? Ice skates Flippers/Fins Sports shoes Rugby boots canvas shoes 2)Which item from the list above would give me the smallest Base of Support (BOS) and why? 3)Define Centre of Gravity (COG) 6)If i want to lower my COG what can i do?

Define the following terms 1)BOS- 2)LOG- 3)COG-

Can you apply the principles of balance to a rugby player about to be tackled.

How can we make the following situations more stable?

Applying the Theory of Balance Why does this not fall over?

Because LOG falls inside the base of support

Sporting Examples for each Principle 1 Principle 2 Principle 3 Principle 4

Who is more balanced? Why?

How do these people remain balanced?

Explain how the position of the centre of gravity is important for balance.

for balance the centre of gravity must be vertically over the base of support.

Identify and explain biomechanical principles that contribute to way the body moves in a side-kick.

Newton’s Laws Newton’s First Law – Inertia Newton’s Second Law – Acceleration Newton’s Third Law – Action/Reaction

Newton’s First Law

Newton’s 1 st Law of Inertia An object at rest tends to remain at rest unless acted upon by some external force. What’s the external force?

That means that if an object is moving, it tends to keep going unless something stops it, like friction or gravity or this guy. Newton’s 1 st Law of Inertia

It also means that an object that is not moving stays put unless something hits it, pushes it, or pulls it. Newton’s 1 st Law of Inertia

Question How does Newton's 1st law apply to a basketball jump shot?

Newton’s 2 nd Law

Newton’s Second Law – Acceleration When a force acts upon a mass, the result is acceleration of that mass (F = m x a) Newton’s 2 nd Law of Acceleration

*The harder you hit the ball, the faster and possibly further it will travel. *Or the softer you hit the ball, the slower and less further it will travel. *The mass will accelerate in the direction the force is applied Newton’s 2 nd Law of Acceleration

Question How does Newton's 2nd law apply to a basketball jump shot?

Newton’s 3 rd Law

For every action, there is an equal and opposite reaction. Newton’s 3rd Law

Question How does Newton's 3rd law apply to a basketball jump shot?

1 st Law – the ball will remain at rest until a force is applied to it. 2 nd Law – the greater the force applied, the greater the acceleration of the ball. 3 rd Law – the runner applies an action force on the ground and the ground applies a reaction force back. Summary

FORCE SUMMATION

Force Summation To give an object momentum in activities such as throwing, kicking or striking an object, the amount of momentum given to the object is determined by ‘the sum of all forces generated by each body part’ (i.e. Force summation).

To gain maximum momentum, the force needs to be generated by: 1.Using as many segments of the body as possible. 2.In the correct sequence, using large muscles first and then the smallest muscles last but fastest. 3.With correct timing. 4.Through the greatest range of motion. Force Summation

To achieve maximum force in the “Block” in the game of basketball the athlete needs to lead with there ____________ then this follows through to their ____________/___________ and finally with the _____________ as they extend up to block the ball coming onto their side of the court. Arms Legs Trunk/back

If you wanted to shoot a 3 pointer in basketball, list the order of muscles (by group, not by individual muscles) that would be used in order to play this shot with correct force summation ________ _________ _______ Lower arm, shoulder, lower legs, back/trunk, upper arm, upper legs 1

Highlight which answer is correct below… A) force summation is the process of using smaller muscles to bigger muscles in the correct timing order to create the greatest force B) force summation is the process of using bigger muscles to smaller muscles in the correct timing order to create the greatest force

Answer B) force summation is the process of using bigger muscles to smaller muscles in the correct timing order to create the greatest force

FORCE SUMMATION LAB Complete force summation lab in 4’s-5’s. Equipment measuring tape/ and ball Task Throw the ball sitting down Throw the ball standing up Throw the ball using a step and throw

Question? To achieve maximum power in a punch the legs and the trunk leads the movement. Explain why?

Question? E.g. the bigger stronger muscles of the upper body/trunk initiate the movement followed by the muscles of the upper arm and finally the lower arm. To gain maximum force in the cross punch all muscles will be used. The muscles need to be used sequentially. The entire movement must be completed over a stable base as this will ensure maximum force.

SUMMARY To gain maximum momentum, 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.

REVISION

What does this relate to.....

Fill in the blanks with the words down the bottom.... The more involved, the greater the force or generated. (eg. A shot-putter should use the legs, hips, ----, shoulders, arms, and in order for maximum distance. speed, wrist, back, body segments Revision Questions

The more body segments involved, the greater the force or speed generated. (eg. A shot-putter should use the legs, hips, back, shoulders, arms, and wrist in order for maximum distance. Revision Questions

Fill in the blanks with the words on the bottom... To gain maximum , the force needs to be generated by: Using as many ---- parts as possible. In the correct sequence (use muscles first & then the muscles last but fastest). With the timing. Though the greatest range of momentum, large, body, smallest, correct, motion

To gain maximum momentum, 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. Revision Questions

To achieve maximum power in a set, the legs leads the movement. Explain why? Revision Questions

Force of Summation The bigger stronger muscles of the lower body in the legs eg- hamstrings and quadriceps initiate the movement followed by the muscles of the trunk/back then the upper arm and finally the lower arm. To gain maximum force in the set all muscles should be used, The muscles need to be used sequentially. The entire movement must be completed over a stable base as this will ensure maximum force, i.e. both feet on the ground.

List the order of joints then muscles used for force summation knee, wrist, back/trunk, ankle,, shoulder, elbow, hip,

Come up with sporting examples that could be used for each of Newton’s Laws... Three sporting examples for each... Revision

Projectile Motion

Speed, Height and Angle of Release Different angle of release affects the distance travelled and the height attained by an object. When a ball is released from ground level, the optimal angle for release for maximum distance is about 45 degrees.

Projectile motion As soon as an object is thrown it becomes a projectile. A projectile is influenced by the principles that govern projectile motion – gravity, air resistance, speed height, and angle of release.

Speed, height & angle of release Different angles of release affect the distance travelled and the height attained by an object. When a ball is released from ground level, the optimal angle for release for maximum distance is about 45 degrees The height of release is important when propelling an object anywhere higher than ground level. If an object needs to clear something higher than ground level (e.g. The cross bar on a goal post), the angle needs to be greater then 45 degrees. 90 degrees 0 degrees 45 degrees Angle of release

Air Resistance Air resistance affect objects in motion by slowing them down. As a body moves through the air, a force is created which tries to resist or stop the movement. This force when an object moves through the air is called drag. The faster a body travels, the greater the drag.

Height of release The height an object is released with determine the distance the object travels e.g.

REVISION

Mix and match Action/ ReactionInertiaAcceleration For every action there is an equal and opposite reaction 3 rd law An object at rest tends to remain at rest until acted upon by an external force 1 st law When a force acts upon a mass, the result is acceleration of that mass 2 nd law

Come up with sporting examples that could be used for each of Newton’s Laws... Three sporting examples for each... Revision

1 st Law – Soccer free kick, hitting a golf ball, rugby conversion 2 nd Law – Golf/cricket/tennis – swinging a club slowly with force gives the ball less momentum 3 rd Law – running, dribbling a basketball, jumping Revision

The runner applies an action force on the ground and the ground applies a reaction force back. The ball will remain at rest until a force is applied to it. The greater the force applied, the greater the acceleration of the ball. Match each statement with the correct Law..... Without looking at your notes. 1 st Law 2 nd Law 3 rd Law