Cardiac Cycle & Conduction System

Organise the blue and green cards to create a flow chart explaining how the conduction system controls the cardiac cycle

Hint:

1. Order the conduction system (blue) cards first

2. Place in the cardiac cycle cards that have bold writing – atrial and ventricular diastole and systole

3. Add the remainder of the cards

The impact of healthy active lifestyle on the skeletal and muscular system

Discuss both the positive and negative impact of participating in different types of physical activity on the joints and muscles of the body

[10 marks]

Common errors

Structure Should start with introduction and end with a conclusion Better to speak about all the positives for all the types of

activity, then all the negatives so that you are not repeating yourself

Lack of examples – give examples of the specific types of activity

Do not develop or explain your points, e.g. Explain what growth plates are and how they are caused

Make your answer more concise – e.g. Try not to mention growth plate injuries more than once.

Standard of written English

Stable positions

Anatomy and Physiology 5

Biomechanics 2

Motion and movement

Specification

Candidates should be able to:

Define Newton’s law of motion

Describe the types of motion produced (linear, angular or general)

Describe the effect of force, direction of the force and the position of application of force on a body

Define centre of mass

Explain the effect of changes on the position of the centre of mass and the area of support when applied to practical techniques

Carry out practical analysis of typical physical actions

Learning Objectives Biomechanics 1

To know and understand Newton’s three laws of motion The types of movement that can be produced

Be able to Apply the laws of motion to explain the type of

movement produced Describe the effect of force in sporting actions

Learning Objectives Biomechanics 2

To know and understand The meaning of the centre of mass and its

influence on motion

Be able to Define centre of mass Explain the effect of changes in position of the

centre of mass and the area of support, including line of gravity

Analyse physical actions

Centre of mass

“The point where all of an objects mass could be considered to be

concentrated, where the body is balanced in all directions.”

Where is the centre of mass?

In a symmetrical/uniform object

COM at geometrical centre

Even distribution of mass around the centre

COM in humans

• Not uniform symmetrical shapes/composition

o Different heights, mass and compositions of fat, muscle, bone and tissue

• Centre of mass is not at a fixed point

Changes in centre of mass

• Location is also dependent on body position

• Could be a point inside or outside the body

• With movement centre of mass rarely stays in the same place

Where is the centre of mass?

Scissors

The Fosbury Flop

Stability

How difficult it is to disturb a body from a balanced position

Stability

Position of the athletes centre of mass

Stability

Size of the athletes support area

Stability

Position of an athletes line of gravity

Line of gravity

• A line extending from the centre of mass vertically down to the ground

Stability

Factors that affect stability and balance in physical activityPosition of athlete’s centre of massPosition of the athlete’s line of gravitySize of the athletes area of support (Number of point in contact with the floor) (Mass of the object)

UNSTABLE LESS STABLE STABLE

Headstand Vs. Handstand

1. Greater area of support

2. Easier to keep the line of gravity within the base of support

3. Centre of mass is closer to the ground

4. More points of contact with the floor

Headstand is more stable

Why?

Linear motion

When a body moves in a straight or curved line with all it’s parts moving

in the same direction and at the same speed.

Angular motion

When a body or part of a body moves in a circle or part of a circle about a

particular point called the axis of rotation

Movement occurs around a fixed point or axis

So what type of motion is this?

Consider…….

1. Flight of javelin

2. Run up

• Javelin

• Torso

• Leg action

• Arm action

Linear motion

Linear motion

Linear motion

Angular motion

• Upper legs rotate about shoulder joints

• Lower legs around the knee joint

• Feet around the ankle joints

Angular motion

• Non-throwing arm rotates about shoulder joint

GENERAL

MOTION

General motion

A combination of linear and angular motion

Question 1 (May 2008)

Movement can be described as linear, angular or general motion

(i) Use a practical example to describe how linear motion can be produced

2 marks

• A force is applied through the centre of mass/gravity of the object.

• A golfer/footballer must hit the ball through its centre of mass/gravity to ensure it travels in a straight line.

Answer 1

Use a practical example to describe how linear motion could be produced

2 marks

1. A force is applied through the centre of mass/gravity of the object

2. A golfer/footballer must hit the ball through its centre of mass/gravity to ensure it travels in a straight line

Exam answer (May 2005)

1b When hitting a ball in tennis an understanding of force is important.

Explain how force can cause the ball to:

(i) Move straight A force is applied through the centre of gravity/mass / the player must hit the ball through the middle (centre of gravity) of the ball.

(ii) Spin 2. A force is applied off centre/eccentric force/hitting a ball on the side will create spin.

Question 2 (May 2004)

During an analysis of practical activities, movement can be described as linear, angular or general motion

Use a practical example to describe how angular motion could be produced

2 marks

Answer 2

Use a practical example to describe how angular motion could be produced

2 marks

1. A force is applied off centre for angular motion to occur eccentric force applied outside centre of mass

2. Applied to a sporting example, e.g. player hits/kicks ball at side to create spin/curve

Question 3

3. Using a practical example from PE and sport, explain how the position of the centre of mass enables a performer to resist motion or external forces [3 marks]

Submax 2 for explanation

1. If the line of gravity lies within the base of support

2. A wide base of support allows more movement of the line of gravity within it

3. If the position of centre of mass is low to the ground

1 mark for a suitable example• A rugby player uses a wider base of support/stance to lower his

centre of mass/gravity to ensure he stays on his feet in a tackle

Question 4

Explain, using a practical example from sport, how either size or direction of force can affect performance in PE and sport [3 marks]

Effects of force

A force can cause…A body at rest to moveA moving body to change directionA moving body to accelerateA moving body to decelerateA body to change shape

Apply each of these to a specific sporting action

Effects of force

What factors affect which of these effects occur and the extent of these effects?

SADSize of the force (Newtons)Application of force (Where the force is applied)Direction of force (In relation to the direction of

movement)

Q4. Explain, using a practical example from sport, how either size or direction of force can affect performance in PE and sport [2 marks]

Explanation 1 mark

1. Size of force affects how far/fast an object travels

2. Direction of force affects the direction/trajectory of the object/distance a flighted object will travel/if direction of force outside of the centre of gravity spin will occur/if direction of force is applied through the centre of gravity it will cause linear motion

3. Larger size of force causes the object to accelerate faster/smaller size of force causes object to accelerate slower

4. Larger size of force causes the object to decelerate faster/smaller size of force causes object to decelerate slower

5. Size of force can change an objects shape more/less

Example 1 mark• A snooker player must apply the correct size of force to the cue ball to ensure the

colour ball reaches the pocket

• A golfer must ensure the ball is struck in the correct direction from the tee to hit the green and/or avoid hazards

Question 5

Apply Newton’s 3 Laws of Motion to a strength training exercise

3 marks

(May 2007)

Q4

Newton’s 1st law of motion

“A body will continue in a state of rest or uniform velocity unless

acted upon by an external force”

Law of Inertia

Newton’s 2nd law of motion

“When a force acts on an object, the rate of change of momentum experienced by the object is proportional to the size of the force and takes

place in the direction in which the force acts”

Law of Acceleration

Newton’s 2nd law of motion

Law of Acceleration

F = ma

F is the applied force

m is the mass of the body/object

a is the acceleration of the body/object

‘The acceleration of an object is directly proportional to the force causing it and is inversely proportional to the mass

of the objects’

Newton’s 3rd law of motion

“For every action there is an equal and opposite reaction”

Action Reaction

The force applied by the ball on the wall is equal and opposite to the force that the wall applies to the ball

1 Law of Inertia/Newtons’ 1st Law Weight/performer will not move unless force applied

2 Law of Acceleration/ Newtons’ 2nd Law

One from:More force applied means a greater weight can be liftedMore force applied causes the weight to be lifted more quicklyAthlete must apply force at end of lift to control weightMore weight lifted requires more force to be applied

3 Law of Reaction/ Newtons’ 3rd Law Performer pushes against resistance/weight and an equal and opposite force is applied back against performer

Q5. Apply Newton’s 3 Laws of Motion to a strength training exercise [3 marks]

Exam question 2010

Using a tennis serve, explain Newton’s 3 laws of motion [5 marks]

1 Law of Inertia/Newtons’ 1st Law The ball will not move until acted upon by a force (the athlete exerts force using racket)

2 Law of Acceleration/ Newtons’ 2nd Law

The greater the force applied to the tennis ball, the greater the acceleration of the tennis ball

3 Law of Reaction/ Newtons’ 3rd Law The force applied to the tennis ball is equal and opposite to the force that the ball applies to the racket

Apply Newton’s 3 Laws of Motion to a tennis serve

Question 6

Describe how the position of the centre of mass can affect a balance. [3 marks]

1. Centre of mass must be over base of support to hold a balance

2. Large area of support makes balance more stable

3. If Centre of mass moves close to the edge of the base of support balance becomes less stable

4. If Centre of mass/line of gravity passes outside base of support balance is lost

5. The lower the centre of mass the more stable the balance

6. If more points of balance are held balance is more stable