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I’ve got the power

I’ve Got The Power! I’ve got the power

©Stan Honda / AFP

What are these people doing? These people are using the power from their muscles to generate electricity.

I’ve Got The Power!

Learning objectives

At the end of the lessons, you will be able to: • describe the roles of aerobic and anaerobic energy systems in the body • measure the power you generate during exercise • estimate aerobic fitness and VO2max

I’ve Got The Power!

Learning objectives

• record and graph the data you obtained to see if there is any correlation between power generated and hours per week of activity • outline the importance of scientific research in informing training and coaching programmes.

I’ve Got The Power! Background science Comparing aerobic and anaerobic respiration Aerobic respiration requires oxygen

Anaerobic respiration doesn’t require oxygen

produces a lot of ATP per glucose molecule occurs in the mitochondria of cells

produces less ATP per glucose molecule occurs in the cytoplasm of cells

used when heart rate and breathing rate rise

used during the first 1–2 minutes of exercise

I’ve Got The Power! Background science We use both aerobic and anaerobic respiration during exercise. Different activities use different proportions of anaerobic and aerobic respiration to provide ATP. Event

% aerobic

% anaerobic

100 m and 200 m sprints

5

95

400 m

20

80

800 m

34

66

1500 m

55

45

5000 m

80

20

10 000 m

90

10

marathon

98

2

I’ve Got The Power! Background science Which energy systems are used in these events?

©PCN Photography

©Press Association Images: Ng Han Guan / AP

©Getty Images: Mark Dadswell

I’ve Got The Power! Background science Aerobic fitness – the ability and efficiency of your lungs, heart and blood vessels to deliver oxygen to your muscles. It is also the ability of your muscles to use the oxygen.

VO2max – a measure of aerobic fitness — the maximum rate you can absorb and use oxygen. At VO2max your heart rate is close to its maximum.

Picture from SPL P200/0070

©Science Photo Library Ltd: PASIEKA

Blood circulation system.

I’ve Got The Power! Background science All sportspeople need good aerobic fitness even if their event uses mainly anaerobic respiration. Find out about the different zonal levels for athletes training.

I’ve Got The Power! Background science Zonal level is the percentage of maximum heart rate at which training takes place. Zone

Zonal level (%)

Outcome of training in zone

energy efficient recovery zone

60–70

develops basic endurance

aerobic zone

70–80

improves blood flow to and from muscles

anaerobic zone

80–90

raises anaerobic threshold (AT)

red line zone

90–100

develops speed; only very fit athletes for a very short time

I’ve Got The Power! Background science Experiment D investigates how your blood pressure changes during exercise. Both diastolic and systolic blood pressure increase with: • height • smoking • tension. Children and young people have lower blood pressure than adults.

I’ve Got The Power! Background science Systolic blood pressure vena cava

• maximum blood pressure during a heart beat right • increases due to atrium the left ventricle right ventricle contracting more forcefully. This pushes more blood out at each beat (increased stroke volume).

aorta

pulmonary artery left atrium

left ventricle

I’ve Got The Power! Background science Diastolic blood pressure • minimum blood pressure during a heart beat • decreases as more blood reaches the active muscles as the resistance in the blood vessels decreases • increases if muscle contraction is sustained or particularly forceful.

lungs vein

artery heart vein

small intestine artery kidneys rest of body

I’ve Got The Power!

Explaining the results

How much power do my leg muscles generate?

• The power generated by the muscles is their rate of doing work. • The total work done depends on:

• mass • step height • how many steps done per minute • activity level — determines how many steps you do per minute.

I’ve Got The Power!

Explaining the results

How much power do my leg muscles generate? • Other factors that influence work done may include: • size of the muscles and number of muscle fibres • energy reserves (ATP, creatine phosphate (CP), glycogen and fat) • anaerobic threshold (when lactate is produced more quickly than it is removed) • efficiency of the muscles to turn chemical energy into mechanical energy.

I’ve Got The Power!

Explaining the results

What does being fit mean? • Heart rate increases with exercise — transports more oxygen to aerobically respiring muscle tissue, so that more ATP is made for muscle contraction. • Return of the heart rate to its resting rate is faster in more aerobically fit individuals. This is the recovery rate.

I’ve Got The Power!

Explaining the results

What does being fit mean?

Percentage oxygen saturation in arterial blood doesn’t change during exercise. The increased demand for oxygen in muscles is met by: • increased heart rate • increased stroke volume (volume of blood leaving the heart at each beat)

• reduced affinity of haemoglobin for oxygen so it gives up its oxygen more readily.

I’ve Got The Power!

Explaining the results

How does the amount of carbon dioxide in my breath change after exercise? There is more carbon dioxide in your breath after exercise, whether aerobic or anaerobic, than at rest.

I’ve Got The Power!

Explaining the results

How does the amount of carbon dioxide in my breath change after exercise? • Aerobic and anaerobic exercise increase the heart rate. • An increase in heart rate and stroke volume, cause the cardiac output (volume of blood leaving the heart in one minute) to increase. • More oxygenated blood reaches the respiring muscles per minute so respiration rate increases, producing more carbon dioxide.

I’ve Got The Power!

Explaining the results

Why does my blood pressure vary with exercise? Diastolic pressure may not increase much or fall during exercise.

Systolic blood pressure increases during exercise because: • heart muscle stretches and contracts more forcefully as more blood returns to the heart • more blood is forced out of the ventricles at each beat (stoke volume increases) So, more oxygenated blood reaches the respiring muscles.

I’ve Got The Power!

Explaining the results

Why does my blood pressure vary with exercise? During very high intensity activity, muscles also respire anaerobically to meet the extra oxygen demands.

• Muscles contract forcefully, which may: • decrease the blood flow in muscles • increase resistance in the blood vessels.

• The diastolic blood pressure may increase if enough skeletal muscles are contracting. After exercise, systolic and diastolic blood pressures return quite quickly to normal resting levels.

I’ve Got The Power!

Your results

What happens to your heart rate when you exercise? Upload your heart rate data to the In the Zone ‘Live Data Zone’ and compare your recovery rate to the national average.

Visit www.getinthezone.org.uk/livedatazone

I’ve Got The Power! Your results

Use data from the ‘Live Data Zone’ to answer the questions below. 1 Compare your class average to the ‘Live Data Zone’ average for heart rate. Use other data to explain these comparisons. 2 Compare the data from the ‘Live Data Zone’ for male and female heart rate.

I’ve Got The Power! Your results

Use the results from your experiments to discuss how the body responds to the changing energy needs during exercise.

What are the long-term changes to the body when we exercise regularly?

I’ve Got The Power! Improving performance ‘All days include running. A typical session may include 6 x 200 m with a 4 minute recovery.’ ‘Thursday is the hardest because we do circuits ©SNS Group before running (lunges, Jay Younger, 400 m Scottish Schools Champion sit-ups, step-ups etc).’ How could Jay use the information from these training sessions to inform future training?

I’ve Got The Power! Improving performance Some research shows that living and training at high altitudes (1 500 m), can improve performance in endurance events (5 000 m).

At high altitudes air is less dense so we inhale less oxygen at each breath, than at sea level. This triggers physiological changes: • increased red blood cell production • increased diffusion capacity of the lungs • increased number of blood vessels in muscle tissues. • increased ability of tissues to use oxygen.

I’ve Got The Power! Improving performance Physical limits There is a limit to human achievement set by powerto-weight ratio. Beyond this limit the benefits of longer legs and stronger muscles are offset by the increased energy needed to move the extra load.

©PCN Photography

Usain Bolt’s 100 m sprint world record of 9.58 s may be within 0.1 s of the absolute limit.

I’ve Got The Power! Improving performance Do all members of a team train in the same way? Which is more effective in team sports, high-intensity interval training or medium-intensity continuous training?

I’ve Got The Power! Improving performance When the body has used up carbohydrates that are available it can then use the lactic acid generated during anaerobic respiration. Interval training generates big lactate loads. The body adapts by increasing numbers of mitochondria in muscle fibres to quickly clear the lactate.

I’ve Got The Power! In the Zone I’ve got the power is the Ages 16–19 component of the In the Zone schools experiments. In the Zone is the Wellcome Trust’s major UK initiative inspired by the 2012 Olympic and Paralympic Games. It has been awarded the London 2012 Inspire Mark and is part of Get Set +, the official London 2012 education programme. For more information about In the Zone, the ‘Live Data Zone’ and downloadable teacher resources go to: www.getinthezone.org.uk.

In the Zone resources are, unless otherwise stated, licensed under a Creative Commons Attribution-NonCommerical-ShareAlike 3.0 UK:England And Wales License. This means that, unless indicated that restrictions apply, you can copy, share and adapt materials as much as you like, as long as it is not for commercial use.

I’ve Got The Power! Credits

In the Zone is commissioned by the Wellcome Trust and delivered by a consortium led by Pearson Education and Guardian Professional Pearson Education Consortium Teacher and student materials produced by Pearson Education Ltd Slide 12 illustration by HL Studios All other illustrations by Oxford Designers and Illustrators Author Sue Hocking, GCE examiner Photo Shoot School – Farringdon Community College, Farringdon, Oxfordshire

Advisors and Contributors to In the Zone Ages 16-19 PowerPoint presentation Jamie Younger, Merchiston School, Edinburgh

Picture credits The publisher would like to thank the following for their kind permission to reproduce their photographs: (Key: b-bottom; c-centre; l-left; r-right; t-top) Alamy Images: PCN Photography 7r, 27; Getty Images: Mark Dadswell 7b, Stan Honda / AFP 2; Press Association Images: Ng Han Guan / AP 7l; SNS Group: 25; Science Photo Library Ltd: PASIEKA 8; Additional images by Clark Wiseman / Studio8 Every effort has been made to trace the copyright holders and we apologise in advance for any unintentional omissions. We would be pleased to insert the appropriate acknowledgement in any subsequent edition of this publication. Where material is owned by a third party, e.g. some photographs, certain restrictions may apply that you have to comply with. In particular, where a copyright line is included on a photograph you must not modify, adapt, or remove that photo from its context.

Thanks to BBC Learning ‘Class Clips’ which feature in the Notes for Slides 5, 9 and 11. The website links to 3rd party material, which are used in this presentation, were correct and up-to-date at the time of publication. It is essential for teachers to preview each weblink before using it in class so as to ensure that the URL is still accurate, relevant and appropriate.