AEROBIC FITNESS 2ND EDITION

Transcription

1 AEROBIC FITNESS 2ND EDITION By John Mason

2 NOTE The information in this book is derived from a broad cross section of resources (research, reference materials and personal experience) from the authors and editorial assistants in the academic department of ACS Distance Education. It is, to the best of our knowledge, composed as an accurate representation of what is accepted and appropriate information about the subject, at the time of publication. The authors fully recognise that knowledge is continually changing, and awareness in all areas of study is constantly evolving. As such, we encourage the reader to recognise that nothing they read should ever be considered to be set in stone. They should always strive to broaden their perspective and deepen their understanding of a subject, and before acting upon any information or advice, should always seek to confirm the currency of that information, and the appropriateness to the situation in which they find themselves. As such, the publisher and author do not accept any liability for actions taken by the reader based upon their reading of this book ISBN PAGE 2

3 CONTENTS INTRODUCTION/PREFACE 5 Differences between aerobic and anaerobic exercise 5 CHAPTER 1 HUMAN BIOLOGY & AEROBIC FITNESS 7 Sources of atp 7 Energy definitions 8 Energy production pathways from different foods 8 What happens during exercise 9 Training response 9 More on fatigue 10 Recovery from exercise 11 Other factors affecting performance 11 Human anatomy 12 The muscular system 14 The respiratory system 16 The circulatory system 17 The physiology of the circulatory system 19 CHAPTER 2 EQUIPMENT & FACILITIES 21 Where to exercise 21 Outdoor areas 22 Clothing and footwear 23 Music 24 Characteristics of equipment 25 Examples of equipment used in aerobic activities 25 Other types of equipment specific to aerobics classes 32 Aerobic home equipment 33 Maintaining equipment 33 Outdoors/park equipment used for aerobic exercises 34 CHAPTER 3 EXERCISES 35 How often, how hard 35 Exercise movement components 36 Running/jogging/walking 39 Cycling 41 Swimming 42 Rowing 42 Stepping & climbing 43 Skipping 43 Ball sports 44 Surfing 45 Horse riding 45 Skating 45 Skiing 45

4 Jumping 45 Tai chi (tai qi) 46 Wilderness areas 46 Safety 46 Gym/class exercises 46 Stretching 49 Muscle conditioning 54 CHAPTER 4 SPECIAL PEOPLE & SITUATIONS 56 Pregnancy 56 Older adults 57 Children 58 People with disabilities &/or handicaps 58 Overweight people 59 Other health problems 60 CHAPTER 5 SAFETY 61 Aerobic classes 61 Safety related issues 61 Safety in other aerobic activities 61 First aid considerations 61 Identifying hazards 63 Pre-screening of clients 65 Legal liabilities for fitness instructors 67 CHAPTER 6 FITNESS TESTING/ASSESSMENT 69 What do we test? 69 What can we measure? 69 Designing fitness tests 77 CHAPTER 7 PROGRAMMING, MOTIVATION & LEADERSHIP 79 Fitness/aerobics class design 79 Programming an exercise session 80 Designing exercise programmes 80 A typical aerobics class 82 Writing an exercise programme 87 Classes for different types of people 88 Configurations or patterns for movement 90 Motivation 90 Dealing with complaints 90 CHAPTER 8 DIRECTORY/APPENDIX 91 Courses 91 Equipment 91

5 INTRODUCTION/PREFACE Aerobic fitness contributes more to your quality of life than perhaps any other aspect of fitness. If someone has reasonable aerobic fitness, they usually have a reasonably healthy heart, lungs and circulatory system. This means that they are able to breathe well, absorb plenty of oxygen into the blood, and efficiently transfer that oxygen throughout the body. It also means that waste products are able to be easily removed from the body by being absorbed into the blood and carried effectively to where they can be eliminated. A key ingredient for ensuring a long life is maintaining a healthy body and mind. By maintaining good aerobic fitness you will generally perform better in intellectual as well as physical pursuits; you will tend to resist illness better, live longer and find it easier to maintain a healthy mental condition. This book will assist you to improve your aerobic fitness levels, and improve your overall health. You will also learn about the body, its functions and how to assist others in obtaining their aerobic fitness goals. To remain aerobically fit, you need to regularly do something which will increase your heart rate above its normal level. This could be exercise, but it could also be work - in fact, it can be any physical activity that causes the heart to beat faster than normal. For this activity to be effective, the heart rate must be sustained at a raised level for at least 20 minutes in each session, and there must be at least three such sessions each week. If it is to be sustained at a raised level for 20 minutes, the session probably needs to go for at least 30 minutes, allowing time for the heart rate to gradually increase at the beginning, and then to gradually decrease at the end of the session. A Modern Epidemic The lack of aerobic fitness is in many ways a problem fostered by modern living. If you are not physically active at work or in your leisure, then it is likely that you could have a serious problem with your aerobic fitness. Combined with this, if you find physical activity difficult (e.g. climbing stairs, going for long walks, etc), and if you are overweight or frequently stressed, then you need to consider paying more attention to your aerobic fitness. What Can You Do The obvious way to improve aerobic fitness is to start exercising regularly by either attending classes or a gym, or perhaps jogging or walking regularly. Playing sport is another option but remember, you need three sessions a week, so playing sport once a week is not sufficient - even if it is for a couple of hours. Many people simply find these options very difficult to commit to. If you feel that way, there are lots of other choices which can be equally beneficial - remember, anything that raises the heart rate can be effective. Consider working in the garden, taking up a part-time job that involves physical activity, playing with your children more often, or if you don t have children of your own, perhaps becoming a scout or guide leader and getting active with a group of teenagers. DIFFERENCES BETWEEN AEROBIC AND ANAEROBIC EXERCISE Exercises fall into two different categories: 1) Anaerobic Exercises Anaerobic exercises concentrate on movements that require no, or minimal oxygen. They are quick, explosive actions that often last no more than 1.5 to 2 minutes. Anaerobic exercises concentrate on improving the strength, speed and power of muscular movements. During the first 2 minutes of exercise, the body cannot get enough oxygen to supply the heart and muscles (which need to work faster than normal). This is referred to as oxygen debt. Once the heart and lungs increase activity though, they are providing oxygen faster than normal to the body, allowing aerobic activity to supply sufficient energy for movement. Anaerobic exercise utilises the ATP (adenosine triphosphate) and creatine phosphate already stored in the muscles to meet energy requirements for the first 15 seconds of exercise. Then the body utilises glucose in the blood and glycogen in the muscles, which still requires no oxygen. This energy system can continue for up to around 2 minutes before demanding oxygen. Energy demand then switches to the aerobic system, where the body can use and deliver oxygen to the muscles. The body therefore cannot work at a fast, powerful manner for longer than 2 minutes because of its need for oxygen. This first phase of exercise produces a quick rise in heart rate. 2) Aerobic Exercise This phase focuses on making heart and respiration rates work more efficiently and, in doing so, they improve cardiorespiratory fitness. The heart rate will increase to a certain level and if it remains there then the aerobic energy system is predominant. Muscles are generally moved repeatedly and for a longer period of time when aerobically exercising and this occurs with the use of oxygen. The body wants more oxygen which it must breathe in allowing it to travel to the muscles (through the blood). Aerobic exercise normally burns carbohydrates already stored in the blood (glucose), muscle and liver (glycogen) to meet the energy needs and then resorts to burning fat to supply energy. This system usually kicks in after approximately 1 minute and can continue for up to an hour or longer. PAGE 5

6 EXAMPLES OF GENERAL AEROBIC AND ANAEROBIC EXERCISES Anaerobic exercises are high energy, usually flat out and rely on stored fuel. A 100-metre sprint, shot put and high jump are all good examples, however aerobic exercise is continuous like cycling, swimming and walking. Even sitting and reading a book is aerobic because the body is breathing at a constant rate which can be maintained. The more intense an aerobic activity is, then the greater the level of fitness that can be achieved. It can be said that aerobics classes, such as those commonly run at a gymnasium, are not just aerobic - because of the varied intensity of exercise they have. Participants may find themselves doing anaerobic-type exercises at some stages during the class. This provides variety to purely aerobic exercise and enables other aspects of fitness to be improved as well, such as muscular strength and endurance. Walking a dog is a common form of aerobic exercise PAGE 6

7 CHAPTER 1 HUMAN BIOLOGY & AEROBIC FITNESS To completely understand how aerobic exercise is performed and fitness is achieved, we need to know what happens from the moment we start to exert ourselves. When a movement in the human body occurs, energy must be released to cause that movement. This energy release occurs via a chemical reaction where adenosine triphosphate (ATP) is converted to adenosine diphosphate (ADP) plus free phosphorus, and large amounts of energy. The energy produced is primarily motion (i.e. the movement of muscles), and heat (which is lost). The body s use of energy is not particularly efficient since a lot of energy is usually lost during any movement. The small amount of available ATP in muscles is only sufficient to support a single explosive muscle contraction - such as throwing a ball, or a golf swing. If a sport, or some other performance, demands repeated muscle contractions then the ATP required must be constantly replenished from other fuel sources in the muscle. ADP can be reconstituted by adding energy to it - this converts it back to ATP. ATP is stored in every cell of the body, and is able to be transported throughout the body. SOURCES OF ATP ATP can be supplied to the body by three different ways: 1) ATP-PC System Here, the compound phosphocreatine is broken down to produce ATP. When phosphocreatine breaks down it produces phosphorus, creatine and energy. The energy produced is then able to be used by ADP to create ATP. Phosphocreatine is then able to be reconstituted with the addition of energy (which comes from foodstuffs and not from stored ATP/ADP reactions). These sources of energy are quickly rebuilt after effort, to the extent that 50% of the energy source is available around 30 seconds later, and 80% of this energy is restored within 2 minutes. 2) Lactic Acid System When a maximal effort is continued beyond the extent of the phosphate energy system, energy is provided from glycogen stored in the muscles. This system involves glucose (or glycogen) going through various chemical processes to produce ATP plus lactic acid. One glucose molecule is broken down into carbon dioxide and water in the presence of oxygen, and in turn, produces two ATP molecules. The amount of ATP produced this way is small. This is a more complex procedure using only carbohydrates as its food fuel, and not requiring oxygen for the process. This energy is used, for example, in 400 metre track races and 100 metre swimming events. Continuous activities which lead to exhaustion in seconds result in maximal values for lactic acid accumulation. A problem with this process is that increased lactic acid levels can affect blood ph. Blood ph should be around 7.3, and never drop below 6.8. Nevertheless, the lactic acid system is self-limiting and so should not normally develop such problems. Generally, the result will be a feeling of fatigue which will cause an athlete (or someone doing heavy bursts of work) to slow down. Once lactic acid is produced, it requires 45 to 60 minutes to be removed, and for the athlete to recover. 3) Oxygen System This process involves the formation of carbon dioxide, water and ATP - from fats, proteins and/or carbohydrates, in the presence of oxygen. This process can produce large amounts of ATP. One molecule of sugar can result in the production of 36 molecules of ATP. This is more complex than the ATP-PC system. The only limiting factor for this system is usually the supply of oxygen. The body will normally try to use this system, and only use other systems to produce ATP if oxygen is in short supply. The short supply of oxygen can occur when: Activity first starts. Activity is placing higher demands on oxygen than what can be supplied by breathing. The Oxygen System is an AEROBIC system. The ATP-PC and Lactic Acid Systems are ANAEROBIC systems. The body uses anaerobic systems for energy supply only when aerobic systems cannot meet the demand. Example If a person is running a marathon, breathing may not be supplying ample oxygen to produce ATP through this system. Hence, the lactic acid system may be used, resulting in a build-up of lactic acid - OR, the ATP-PC system may be used, resulting in a depletion of phosphocreatine in the muscles. After completing exercise, there may be a lactic acid build-up, and if so, the body needs to remove this excess. This lactic acid removal requires energy which is supplied aerobically - hence extra oxygen may be required. This extra oxygen requirement (after exercise) is called the oxygen debt. Krebs Cycle This is one particular series of reactions occurring in the oxygen system. Two main chemical reactions occur in this cycle: 1. Production of carbon dioxide. 2. Oxidation (i.e. removal of electrons). PAGE 7