Physical Fitness Module.pdf

PHYSICAL FITNESS MODULE (SpSc 1011) Prepared By: Zerihun Birhanu (PhD) (Bahir Dar University) Haileyesus Gedefaw (PhD) (Dilla University) August, 2019 ...

PHYSICAL FITNESS MODULE (SpSc 1011) Prepared By: Zerihun Birhanu (PhD) (Bahir Dar University) Haileyesus Gedefaw (PhD) (Dilla University) August, 2019  Preface Since the beginning of time, survival has been a daily struggle. Simply staying alive was physically demanding. Yet, humans in industrialized societies over the last 150 years have come spoiled. We live in our minds so much of the time that we have almost forgotten that we have a body many people work in offices who make their living by reading, writing, speaking, and thinking, but seldom by physical labor. Regular physical exercise does the body good. Physical exercise empowers natural health advocates to take active measures to combat disuse atrophy. Physical fitness has a vital role in the life of men from time immemorial. The progress of the nation lies in the hands of people, who are healthy and physically fit. Every individual should develop physical fitness for a happy and effective living. Physical fitness is the ability to live a full and balanced life. The totally fit person has a healthy and happy outlook towards life. Fitness is the young man‘s absolute necessity. It breads breeds self-reliance and keeps man mentally alert. Physical fitness is essential for human beings to adjust well with his environment as his mind and body are in complete harmony. In order to get physical fitness one has to involve in a regular physical exercise program. Our bodies demand to be used. Failure to use them results in your muscles deteriorating, at a steady and progressive rate. Thus, everyone should develop sensible habits of exercise that they can stick to for the rest of their lives. To help you understand about physical fitness and related issues, this module provides you all the necessary information regarding what physical fitness is, the various components of physical fitness, means by which physical fitness is developed, methods of assessing physical fitness and the health benefits of physical exercise.  Table of Contents Unit 1: Concepts of physical fitness....................................................................................1 1.1. Meanings and definitions of terms..................................................................2 1.1.1. Physical fitness.....................................................................................2 1.1.2. Physical Activity.................................................................................3 1.1.3.Physical exercise...................................................................................4 1.1.4. Sport.....................................................................................................5 1.2. General principles of fitness training.............................................................6 1.2.1 Principle of Overload............................................................................6 1.2.2 FIIT Principle.........................................................................................7 1.2.3 Principle of Rest, Recovery and Periodization....................................10 1.2.4 Principle of Reversibility.....................................................................12 1.2.5 Principle of Individual Deference........................................................13 Unit 2: The Health Benefits of Physical Activity.............................................................16 2.1................................................................................................................Physic al Activity and Hypokinetic Diseases/Conditions........................................17 2.2................................................................................................................Physic al Activity and Cardiovascular Diseases.......................................................22 2.2.1......................................................................................................Corona ry Heart Disease...................................................................................22 2.2.2......................................................................................................Hypert ension...................................................................................................23 2.2.3......................................................................................................Hyper- cholesterolemia and Dyslipidemia.......................................................25 2.2.4......................................................................................................Diabet es Mellitus............................................................................................26 2.2.5......................................................................................................Obesit y and Overweight.................................................................................27 2.2.6......................................................................................................Metab olic Syndrome......................................................................................28 2.2.7......................................................................................................Aging..............................................................................................................29 2.3................................................................................................................Physic al activity and postural deformity................................................................30 2.3.1......................................................................................................Muscul oskeletal disease and disorders............................................................31 Unit 3: Making Well-Informed Food Choices..................................................................34 3.1. Sound Eating Practices.................................................................................34 3.1.1......................................................................................................Macro nutrients................................................................................................35 3.1.2......................................................................................................Micron utrient..................................................................................................35 3.1.3......................................................................................................Calorie s (Food Energy)....................................................................................35  3.2................................................................................................................Nutriti on and Physical Performance........................................................................43 3.2.1......................................................................................................Nutriti on Before Exercise...............................................................................44 3.2.2......................................................................................................Nutriti on During Exercise..............................................................................47 3.2.3......................................................................................................Nutriti on After Exercise.................................................................................50 3.2.4......................................................................................................How to Plan Your Training Diet.......................................................................52 Unit 4: Health related components of fitness and principles of exercise prescription.....54 4.1. Health Related Components of Fitness……………………………………..54 4.1.1......................................................................................................Cardio respiratory Fitness................................................................................55 4.1.2......................................................................................................Muscle Fitness..................................................................................................55 4.1.3......................................................................................................Flexibi lity.......................................................................................................59 4.1.4......................................................................................................Body Composition........................................................................................61 4.2. Principles of exercise prescription for health and fitness.............................66 4.2.1......................................................................................................Fitness Goals...................................................................................................67 4.2.2......................................................................................................Mode of Exercise...........................................................................................69 4.2.3......................................................................................................Warm Up.........................................................................................................69 4.2.4......................................................................................................Primar y Conditioning Period: The Workout Plan.........................................70 4.2.5......................................................................................................Cool – Down...................................................................................................71 4.3. Individualizing workout...............................................................................71 4.4. Means and methods of developing cardiorespiratory fitness........................72 4.4.1......................................................................................................Exercis e prescription for Cardiorespiratory Fitness........................................72 4.4.2......................................................................................................Startin g and Maintaining a Cardiorespiratory Fitness Program.....................77 4.4.3......................................................................................................Trainin g Techniques.......................................................................................79 4.5. Means and methods of developing muscle fitness........................................82 4.5.1 Guiding Principles for Designing a Strength and Endurance Program82 4.5.2 Types of Weight Training Programs....................................................84 4.5.3 Exercise Prescription for Weight Training: an overview....................85 4.5.4 Developing an Individualized Exercise Prescription...........................87 4.6. Means and methods of developing flexibility...............................................88 4.6.1 Exercise Prescription for Improving Flexibility..................................88  4.6.2 How to Avoid Hazardous Exercise......................................................89 Unit 5: Assessment of fitness components........................................................................91 5.1................................................................................................................Evalua ting Health Status..........................................................................................91 5.2................................................................................................................Assess ment of cardiorespiratory fitness..................................................................92 5.2.1......................................................................................................The 1.5 Mile Run Test................................................................................92 5.2.2......................................................................................................The 1 Mile Walk Test....................................................................................94 5.2.3......................................................................................................The Cycle Ergometer Fitness Test..............................................................95 5.2.4......................................................................................................The Step Test...............................................................................................95 5.3................................................................................................................Assess ment of Muscle Fitness.................................................................................96 5.3.1......................................................................................................Assess ing muscular strength...........................................................................96 5.3.2......................................................................................................Assess ing muscular endurance.......................................................................98 5.4................................................................................................................Assess ment of flexibility.......................................................................................101 5.4.1......................................................................................................Trunk Flexibility...........................................................................................102 5.4.2......................................................................................................Should er Flexibility.......................................................................................102 5.5................................................................................................................Assess ment of body composition..........................................................................103 5.5.1......................................................................................................The Skin Fold Test....................................................................................104 5.5.2......................................................................................................Estima tion of Body Composition: Other Field Techniques.........................107 Reference......................................................................................................................109  UNIT ONE CONCEPTS OF PHYSICAL FITNESS UNIT OBJECTIVES By the end of this unit you should be able to:  Define physical fitness, physical activity, physical exercise and sport  Understand the benefits of physical fitness  Realize general principles of fitness training  Make behaviour modification to stay fit  INTRODUCTION As most college students do, you have probably set goals. Obviously, your individual goals differ from those of your fellow classmates, but everyone‘s goals share one common attribute: their intention to improve individual wellbeing. However, there are as many ideas about how to do that as there are individuals. Do your goals involve making more money, achieving better health, improving your relationships? Holistic wellness involves all those aspects of life and more. Maintaining physical fitness and ever stayed conditioned has a lion share for wellness though. This unit explains the concepts of physical fitness which might assist you to stay fit to exude confidence, optimism, and self-efficacy; they have the energy reserves to do what needs to be done today and to plan for a better tomorrow. The most effective and transformative goals are those designed to achieve the highest level of personal wellness. Physical Fitness Course Module Page 1 1.1. Meanings and Definitions of Terms 1.1.1 Physical fitness It is an ability to meet the ordinary, as well as unusual demands of daily life safely and effectively without being overly fatigued. Simply it is the body‘s ability to function effectively and efficiently, and contributes the total quality of life. The totally fit person has a healthy and happy outlook towards life. Fitness is the young man‘s absolute necessity. It breeds self- reliance and keeps man mentally alert. Physical fitness is essential for human beings to adjust well with his environment as his mind and body are in complete harmony. It is generally agreed that physical fitness is an important part of the normal growth and development of a child, a generic definition regarding the precise nature of physical fitness has not been universally accepted. Through research and scholarly inquiry, it is clear that the multi- dimensional characteristics of physical fitness can be divided into two areas: health related physical fitness and skill related physical fitness (see Unit Four). Clarke and Clarke (1989) found that physical fitness is not a static factor and it varies from individual to individual and in the same person from time to time depending on factors. Physical fitness is probably the most popular and frequently used term in physical education. The most important objective of physical educators is to develop physical fitness. According to Nixon and cozens (1964), it was the desire to establish a scientific approach to the development of physical fitness which formed the basis of the first meeting of physical educators in 1885 when the profession of physical education originated. The United States president‘s Council on physical fitness and sports defined the terms ―physical fitness as the ability to carry out daily task with vigor and alertness, without undue fatigue, with ample energy to enjoy leisure time pursuits and to meet unforeseen emergencies‖ (Clarke, 1971). Physical Fitness Course Module Page 2 General fitness implies the ability of a person to live most effectively with his and her potentials, which depend upon the physical, mental, emotional, social and spiritual components of fitness which are highly interrelated. Activity 1.1 Dear Student, discuss on the following questions with your partners. 1. Would you try to provide a very simple working definition for the term physical fitness? 2. How do you further classify physical fitness? 3. Tell the conceptual dimensions of fitness in general. 1.1.2 Physical Activity It is bodily movement produced by skeletal muscles that results in energy expenditure. The term, physical activity, does not require or imply any specific aspect or quality of movement. The term encompasses all types, intensities, and domains. Although the term ―physical activity‖ has been used often as a short-hand description for moderate-to-vigorous-intensity forms of physical activity, given current interest and discussions about physical activity of intensities less than moderate-intensity, the term ―physical activity‖ should be used when discussing the full range of intensities. More specific descriptors such as sedentary behavior, light, moderate, vigorous, or moderate-to-vigorous should be used when talking about a specific range of intensities. Based on predominant physiologic effect, physical activity can be categorized in to aerobic physical activity and anaerobic physical activity. Aerobic physical activity includes forms of activity that are intense enough and performed long enough to maintain or improve an individual‘s cardiorespiratory fitness. Aerobic activities such as walking, basketball, soccer, or dancing, commonly require the use of large muscle groups. The connection between aerobic activities such as these and cardiorespiratory fitness is sufficiently close that the term ―aerobic capacity‖ is considered equivalent to cardiorespiratory fitness. Technically, aerobic physical activity includes any activity that could be maintained using only oxygen-supported metabolic energy pathways and could be continued for more than a few minutes. However, in both common and scientific usage, ―aerobic‖ activity has come to mean physical activity that would be expected to maintain or improve cardiorespiratory fitness or Physical Fitness Course Module Page 3 aerobic capacity. Whereas, anaerobic physical activity refers to high-intensity activity that exceeds the capacity of the cardiovascular system to provide oxygen to muscle cells for the usual oxygen consuming metabolic pathways. Anaerobic activity can be maintained for only about 2 to 3 minutes. Sprinting and power lifting are examples of anaerobic physical activity. 1.1.3 Physical Exercise The term "exercise" has been used interchangeably with "physical activity", and, in fact, both have a number of common elements. For example, both physical activity and exercise involve any bodily movement produced by skeletal muscles that expends energy, are measured by kilocalories ranging continuously from low to high, and are positively correlated with physical fitness as the intensity, duration, and frequency of movements increase. Exercise, however, is not synonymous with physical activity: it is a subcategory of physical activity. Exercise is physical activity that is planned, structured, repetitive, and purposive in the sense that improvement or maintenance of one or more components of physical fitness is an objective. The formula relating physical activity and exercise is: kcalExerclse + kcalNonexercise` = kcalTotal daily Physical activity Physical activity is complex behavior, however, and may be meaningfully partitioned into other categories mutually exclusive of each other but not activity except sleep. However, it is more likely to be an important part of some categories of physical activity than of others. For example, virtually all conditioning and many sports activities are performed to improve or maintain components of physical fitness. In such instances they are planned, structured, and, more often than not, repetitive. Activities such as occupational, household and many daily tasks are typically performed in the most efficient manner possible. These physical activities are done with little regard to physical fitness and are often structured with conservation of energy expenditure as a goal. However, a worker may plan and structure the performance of some work tasks in a less efficient manner to Physical Fitness Course Module Page 4 develop muscular strength or to "burn up" calories. Similarly, a person may plan and structure the performance of household or other tasks in a labor producing rather than a labor-saving manner. Tasks regularly performed in this manner are considered exercise. Generally, Exercise describes as planned structured and repetitive bodily movement done to improve or maintain one or more components of physical fitness and is subset of physical activity. Exercise is usually goal related and designed in the sense that the improvement or maintenance of one or more components of physical fitness (i.e., endurance, strength, flexibility etc…). Activity 1.2 Dear Student, would you try to mention the elements of Physical Activity and Exercise in the box below? Physical Activity Exercise 1.1.4 Sport It is an organized, competitive form of play. Some persons view sport simply as an organized form of play, which might put it closer to physical education as we have defined it. However, close consideration will show that sport has traditionally involved competitive activities. When we refer to sport as ―organized‖ competitive activity, we mean that the activity has been refined and formalized to some degree- that is, some definite form or process involved. Rules, whether they are written or not, are involved in this form of activity, and these rules or procedures can not be changed during the competition, though new ones may involve from one episode to the next. Sport is, above all, competitive activity. We cannot think of sport without thinking of competition, for without the competition, sport becomes simply play or recreation. Physical Fitness Course Module Page 5 Play can at times be sport, but strictly speaking, sport is never simple play; the competitive aspect is essential to the nature of sport. Activity 1.3 Dear Student, discuss on the following questions with your partners. 1. One way of defining sport is as “organized” competitive activity, what do we mean by that? 2. And how do you differentiate sport from other forms of exercise and physical activity? 1.2 General Principles of Fitness Training The human body adapts well when exposed to stress. The term stress, within the context of exercise, is defined as an exertion above the normal, everyday functioning. The specific activities that result in stress vary for each individual and depend on a person‘s level of fitness. For example, a secretary who sits at a desk all day may push his/her cardiorespiratory system to its limits simply by walking up several flights of stairs. For an avid runner, resistance training may expose the runner‘s muscles to muscular contractions the athlete is not accustomed to feeling. Although stress is relative to each individual, there are guiding principles in exercise that can help individuals manage how much stress they experience to avoid injury and optimize their body‘s capacity to adapt. Knowing a little about these principles provides valuable insights needed for organizing an effective fitness plan. 1.2.1 Principle of Overload Consider the old saying, ―No pain, No gain.‖ Does exercise really have to be painful, as this adage implies, to be beneficial? Absolutely not. If that were true, exercise would be a lot less enjoyable. Perhaps a better way to relay the same message would be to say that improvements are driven by stress. Physical stress, such as walking at a brisk pace or jogging, places increased stress on the regulatory systems that manage increased heart rate and blood pressure, increased energy production, increased breathing, and even increased sweating for temperature regulation. As these subsequent adaptations occur, the stress previously experienced during the same Physical Fitness Course Module Page 6 activity, feels less stressful in future sessions. As a result of the adaptation, more stress must be applied to the system in order to stimulate improvements, a principle known as the overload principle. For example, a beginning weightlifter performs squats with 10 repetitions at 150 pounds. After 2 weeks of lifting this weight, the lifter notices the 150 pounds feels easier during the lift and afterwards causes less fatigue. The lifter adds 20 pounds and continues with the newly established stress of 170 pounds. The lifter will continue to get stronger until his/her maximum capacity has been reached, or the stress stays the same, at which point the lifter‘s strength will simply plateau. This same principle can be applied, not only to gain muscular strength, but also to gain flexibility, muscular endurance, and cardiorespiratory endurance. Activity 1.4 Dear Student, discuss on the following questions with your partners. 1. Does the old saying, “No pain, No gain” satisfy the principle of overload? 2. If we don’t respect the principle of overload during training what would be the ultimate consequence? 1.2.2 FITT Principle In exercise, the amount of stress placed on the body can be controlled by four variables: Frequency, Intensity, Time (duration), and Type, better known as FITT. The FITT principle, as outlined by the American College of Sports Medicine (ACSM) falls under the larger principle of overload. A. Frequency and Time Each variable can be used independently or in combination with other variables to impose new stress and stimulate adaptation. Such is the case for frequency and time. Frequency relates to how often exercises are performed over a period of time. In most cases, the number of walking or jogging sessions would be determined over the course of a week. A Physical Fitness Course Module Page 7 beginner may determine that 2–3 exercise sessions a week are sufficient enough to stimulate improvements. On the other hand, a seasoned veteran may find that 2–3 days is not enough to adequately stress the system. According to the overload principle, as fitness improves, so must the stress to ensure continued gains and to avoid plateauing. The duration of exercise, or time, also contributes to the amount of stress experienced during a workout. Certainly, a 30-minute brisk walk is less stressful on the body than a 4-hour marathon. Although independent of one another, frequency and time are often combined into the blanket term, volume. The idea is that volume more accurately reflects the amount of stress experienced. This can be connected to the progression principle. For example, when attempting to create a jogging plan, you may organize 2 weeks like this:  Week 1: three days a week at 30 minutes per session  Week 2: four days a week at 45 minutes per session At first glance, this might appear to be a good progression of frequency and time. However, when calculated in terms of volume, the aggressive nature of the progression is revealed. In week 1, three days at 30 minutes per session equals 90 minutes of total exercise. In week two, this amount was doubled with four days at 45 minutes, equaling 180 minutes of total exercise. Doing too much, too soon, will almost certainly lead to burnout, severe fatigue, and injury. The progression principle relates to an optimal overload of the body by finding an amount that will drive adaptation without compromising safety. B. Type of Exercise Simply put, the type of exercise performed should reflect a person‘s goals. In cardiorespiratory fitness, the objective of the exercise is to stimulate the cardiorespiratory system. Other activities that accomplish the same objective include swimming, biking, dancing, cross country skiing, aerobic classes, and much more. As such, these activities can be used to build lung capacity and improve cellular and heart function. Physical Fitness Course Module Page 8 However, the more specific the exercise, the better. While vigorous ballroom dancing will certainly help develop the cardiorespiratory system, it will unlikely improve a person‘s 10k time. To improve performance in a 10k, athletes spend the majority of their time training by running, as they will have to do in the actual 10k. Cyclists training for the Tour de France, spend up to six hours a day in the saddle, peddling feverishly. These athletes know the importance of training the way they want their body to adapt. This concept, called the principle of specificity, should be taken into consideration when creating a training plan. In this discussion of type and the principle of specificity, a few additional items should be considered. Stress, as it relates to exercise, is very specific. There are multiple types of stress. The three main stressors are metabolic stress, force stress, and environmental stress. Keep in mind, the body will adapt based on the type of stress being placed on it. Metabolic stress results from exercise sessions when the energy systems of the body are taxed. For example, sprinting short distances requires near maximum intensity and requires energy (ATP) to be produced primarily through anaerobic pathways, that is, pathways not requiring oxygen to produce ATP. Anaerobic energy production can only be supported for a very limited time (10 seconds to 2 minutes). However, distance running at steady paces requires aerobic energy production, which can last for hours. As a result, the training strategy for the distance runner must be different than the training plan of a sprinter, so the energy systems will adequately adapt. Likewise, force stress accounts for the amount of force required during an activity. In weightlifting, significant force production is required to lift heavy loads. The type of muscles being developed, fast-twitch muscle fibers, must be recruited to support the activity. In walking and jogging, the forces being absorbed come from the body weight combined with forward momentum. Slow twitch fibers, which are unable to generate as much force as the fast twitch fibers, are the type of muscle fibers primarily recruited in this activity. Because the force requirements differ, the training strategies must also vary to develop the right kind of musculature. Physical Fitness Course Module Page 9 Environmental stress, such as exercising in the heat, places a tremendous amount of stress on the thermoregulatory systems. As an adaptation to the heat, the amount of sweating increases as does plasma volume, making it much easier to keep the body at a normal temperature during exercise. The only way to adapt is through heat exposure, which can take days to weeks to properly adapt. In summary, to improve performance, being specific in your training, or training the way you want to adapt, is paramount. C. Intensity Intensity, the degree of difficulty at which the exercise is carried out, is the most important variable of FITT. More than any of the other components, intensity drives adaptation. Because of its importance, it is imperative for those beginning a fitness program to quantify intensity, as opposed to estimating it as hard, easy, or somewhere in between. Not only will this numeric value provide a better understanding of the effort level during the exercise session, but it will also help in designing sessions that accommodate individual goals. How then can intensity be measured? Heart rate is one of the best ways to measure a person‘s effort level for cardiorespiratory fitness. Using a percentage of maximum lifting capacity would be the measure used for resistance training. Activity 1.5 Dear Student, recall the FITT principle and complete the exercise recommendation for an average adult. Principle Training Recommendations Frequency Intensity Time Type 1.2.3 Principle of Rest, Recovery, and Periodization Physical Fitness Course Module Page 10 For hundreds of years, athletes have been challenged to balance their exercise efforts with performance improvements and adequate rest. The principle of rest and recovery (or principle of recuperation) suggests that rest and recovery from the stress of exercise must take place in proportionate amounts to avoid too much stress. One systematic approach to rest and recovery has led exercise scientists and athletes alike to divide the progressive fitness training phases into blocks, or periods. As a result, optimal rest and recovery can be achieved without overstressing the athlete. This training principle, called periodization, is especially important to serious athletes but can be applied to most exercise plans as well. The principle of periodization suggests that training plans incorporate phases of stress followed by phases of rest. Training phases can be organized on a daily, weekly, monthly, and even multi-annual cycles, called micro-, meso-, and macrocycles, respectively. An example of this might be: Table 1.1:- Periodization Example Week Frequency Intensity Time Type 1 3 days 40% HRR 25 min Walk 2 4 days 40% HRR 30 min Walk 3 4 days 50% HRR 35 min Walk 4 2 days 30% HRR 30 min Other As table 1.1 shows, the volume and intensity changes from week 1 to week 3. But, in week 4, the volume and intensity drops significantly to accommodate a designated rest week. If the chart were continued, weeks 5-7 would be ―stress‖ weeks and week 8 would be another rest week. This pattern could be followed for several months. Without periodization, the stress from exercise would continue indefinitely eventually leading to fatigue, possible injury, and even a condition known as overtraining syndrome. Overtraining syndrome is not well understood. However, experts agree that a decline in performance resulting from psychological and physiological factors cannot be fixed by a few days‘ rest. Instead, weeks, months, and sometimes even years are required to overcome the symptoms of overtraining syndrome. Symptoms include the following:  weight loss Physical Fitness Course Module Page 11   loss of motivation  inability to concentrate or focus  feelings of depression  lack of enjoyment in activities normally considered enjoyable  sleep disturbances  change in appetite Activity 1.6 Dear Student, discuss on the following questions with your partners. 1. What is the underlined principle of rest, recovery and periodization for better physical performance and health? 2. Define Microcycle, Mesocycle, and Macrocycle of Periodization. 3. How do you avoid overtraining? 1.2.4 Principle of Reversibility Chronic adaptations are not permanent. As the saying goes, ―Use it or lose it.‖ The principle of reversibility suggests that activity must continue at the same level to keep the same level of adaptation. As activity declines, called detraining, adaptations will recede. In cardiorespiratory endurance, key areas, such as VO2max, stroke volume, and cardiac output all declined with detraining while submaximal heat rate increased. In one study, trained subjects were given bed rest for 20 days. At the end of the bed rest phase, VO2max had fallen by 27% and stroke volume and cardiac output had fallen by 25%. The most well-trained subjects in the study had to train for nearly 40 days following bed rest to get back into pre-rest condition. In a study of collegiate swimmers, lactic acid in the blood after a 2-minute swim more than doubled after 4 weeks of detraining, showing the ability to buffer lactic acid was dramatically affected. Not only is endurance training affected, but muscular strength, muscular endurance, and flexibility all show similar results after a period of detraining. Physical Fitness Course Module Page 12 Activity 1.7 Dear Student, discuss on the following questions with your partners. 1. What does “Use it or lose it” refers considering the principle of reversibility? 2. What are the detraining effects of exercise? 1.2.5 Principle of Individual Differences While the principles of adaptation to stress can be applied to everyone, not everyone responds to stress in the same way. In the HERITAGE Family study, families of 5 (father, mother, and 3 children) participated in a training program for 20 weeks. They exercised 3 times per week, at 75% of their VO2max, increasing their time to 50 minutes by the end of week 14. By the end of the study, a wide variation in responses to the same exercise regimen was seen by individuals and families. Those who saw the most improvements saw similar percentage improvements across the family and vice versa. Along with other studies, this has led researchers to believe individual differences in exercise response are genetic. Some experts estimate genes to contribute as much as 47% to the outcome of training. In addition to genes, other factors can affect the degree of adaptation, such as a person‘s age, gender, and training status at the start of a program. As one might expect, rapid improvement is experienced by those with a background that includes less training, whereas those who are well trained improve at a slower rate. Activity 1.8 Dear Student, discuss on the following questions with your partners. 1. What does the principle of individual difference states? 2. What factors can affect the degree of adaptation to exercise stress? Physical Fitness Course Module Page 13 UNIT SUMMARY  Physical activity: any activity that requires skeletal muscle and requires energy aimed at improving health.  Exercise: a subset of physical activity that is planned and structured aimed at improving fitness.  Health related components of fitness: types of activities dedicated to improving physical fitness categorized as cardiorespiratory endurance, muscular strength and endurance, flexibility, and body composition.  Skills related components of fitness: types of activities dedicated to improving physical skills categorized as speed, agility, coordination, balance, power, and reaction time.  Principles of adaptations to stress: guidelines related to managing the application of stress during physical activity/exercise.  Overload Principle: a principle of adaptation to stress suggesting the amount of stress applied during exercise must exceed a threshold level to stimulate adaptation.  Volume: the term used to describe ―how much‖ stress is being applied by combining the duration and frequency of exercise.  Progression principle: a principle relating to how much additional stress that can safely be introduced to gradually improve fitness without risking injury or overuse.  Specificity: the principle of stress suggesting activities should be closely centered around the primary outcome goal, i.e. train the way you want to adapt. Physical Fitness Course Module Page 14  Reversibility: the principle that adaptations to stress can be lost over time if training is modified or stopped.  Principle of rest and recovery: the concept that adaptation not only requires overload but also requires rest to avoid overstressing the body.  Periodization: a method of organizing workouts into blocks or periods. These cycles consist of work/stress periods and rest periods.  Overtraining syndrome: a condition of chronic stress from physical activity affecting the physical and psychological states of an individual or athlete.  Detraining: the act of no longer training at all or decreasing the amount of training. SELF-TEST EXERCISE 1. The term exercise refers to physical activity that is: a. Discontinuous and unplanned but designed to improve fitness b. Planned, structured, and repetitive designed to improve fitness c. Not a contributor to physical fitness d. Random and unstructured 2. Which of the following is NOT considered a skill-related fitness component? a. Coordination c. Balance b. Flexibility d. Agility 3. During the initial phase of an exercise program, a beginner should: a. Begin slowly, exercising at a low intensity and gradually increasing volume b. Keep intensity high, exercise at the high end of the target heart rate range c. Perform short but intense bouts of activity d. Exercise 5-7 days per week 4. The body‘s ability to adapt to gradual increases in the amount of exercise is the principle of: a. Overload c. Reversibility b. Specificity d. Assessment Physical Fitness Course Module Page 15 5. The amount of overload needed to maintain or improve one‘s fitness level is NOT determined by: a. Time (duration) c. Frequency b. Intensity d. Specificity 6. Another term used for organizing your training into phases or cycles is: a. Specificity c. Periodization b. Skill training d. Overload UNIT TWO THE HEALTH BENEFITS OF PHYSICAL ACTIVITY UNIT OBJECTIVES By the end of this unit students should be able to:  Describe the health benefits of physical activity  Identify diseases which are associated with a sedentary lifestyle and the major risk factors for these diseases  Realize regular physical activity in terms of disease prevention and healthy aging?  Estimate physical activity needed for improved health benefits?  Identify physical activities suitable for typical people, and how often should they exercise?  INTRODUCTION Physical activity and physical fitness have been linked with health and longevity since ancient times. The earliest records of organized exercise used for health promotion are found in China, Physical Fitness Course Module Page 16 around 2500 BC. However, it was the Greek physicians of the fifth and early fourth centuries BC who established a tradition of maintaining positive health through ‗regimen‘; the combination of correct eating and exercise. Hippocrates (460–370 BC), often called the Father of Modern Medicine, wrote all parts of the body which have a function, if used in moderation and exercised in labours in which each is accustomed, become thereby healthy, well-developed and age more slowly, but if unused and left idle they become liable to disease, defective in growth and age quickly. This unit deals with physical activity trends, risk factors associated with chronic diseases, the role of regular physical activity in disease prevention and health, and physical activity guidelines and recommendations for improved health. 2.1. Physical Activity and Hypokinetic Diseases/ Conditions Hypokinetic diseases are conditions related to inactivity or low levels of habitual activity. The term ―hypokinetic‖ was coined by Kraus and Raab in their book Hypokinetic Disease (Kraus & Raab, 1961). This term is now widely accepted and can be used to describe many of the diseases and conditions associated with inactivity and poor fitness such as those conditions outlined in Physical Activity and Health: A Report of the Surgeon General (USDHSS, 1996). Our increased reliance on technology has substantially lessened work-related physical activity, as well as the energy expenditure required for activities of daily living like cleaning the house, washing clothes and dishes, mowing the lawn, and traveling to work. What would have once required an hour of physical work now can be accomplished in just a few seconds by pushing a button or setting a dial. As a result, more time is available to pursue leisure activities. The unfortunate fact is, however, that many individuals do not engage in physical activity during their leisure time. Although the human body is designed for movement and strenuous physical activity, exercise is not a part of the average lifestyle. One cannot expect the human body to function optimally and to remain healthy for extended periods if it is abused or is not used as intended. Physical Physical Fitness Course Module Page 17 inactivity has led to a rise in chronic diseases. Some experts believe that physical inactivity is the most important public health problem in the 21st century. Each year at least 1.9 million people die as a result of physical inactivity. Data from the Aerobics Center Longitudinal Study (2009) indicated that low cardiorespiratory fitness accounts for substantially more deaths (16%) compared to other risk factors (i.e., obesity 2–3%; smoking 8–10%; high cholesterol 2–4%; diabetes 2–4%; and hypertension 8–16%). Individuals who do not exercise regularly are at a greater risk for developing chronic diseases such as coronary heart disease (CHD), hypertension, hypercholesterolemia, cancer, obesity, and musculoskeletal disorders (see figure 1.1). Figure 1.1 Role of physical activity and exercise in disease prevention and rehabilitation. For years, exercise scientists and health and fitness professionals have maintained that regular physical activity is the best defense against the development of many diseases, disorders, and illnesses. In 1995, Center for Disease Control (CDC) and the American College of Sports Medicine (ACSM) recommended that every adult should accumulate 30 min or more of moderate-intensity physical activity on most, preferably all, days of the week. Physical Fitness Course Module Page 18 Since 1995, new scientific evidence has increased our understanding of the benefits of physical activity for improved health and quality of life. In light of these findings, the American Heart Association (AHA) and the ACSM updated physical activity recommendations for healthy adults and older adults. These recommendations address how much and what kind of physical activity are needed to promote health and reduce the risk of chronic disease in adults. Table 1.1 summarizes the ACSM and AHA physical activity recommendations for adults. The recommended amounts of physical activity are in addition to routine activities of daily living (ADLs) such as cooking, shopping, and walking around the home or from the parking lot. The intensity of exercise is expressed in metabolic equivalents (METs). A MET is the ratio of the person‘s working (exercising) metabolic rate to the resting metabolic rate. One MET is defined as the energy cost of sitting quietly. Table 1.1 Summary of the ACSM and AHA physical activity recommendations for adults *Combinations of moderate and vigorous-intensity may be performed to meet recommendation (e.g., jogging 20 min on 2 days and brisk walking on 2 other days). *Multiple bouts of moderate intensity activity, each lasting at least 10 min, can be accumulated to meet the minimum duration of 30 min. Moderate-intensity aerobic activity (3.0–6.0 METs or 5 or 6 on a 10-point perceived exertion scale) is operationally defined as activity that noticeably increases heart rate and lasts more than 10 min (e.g., brisk walking for 15 min). Vigorous-intensity activity (>6.0 METs or 7 or 8 on a Physical Fitness Course Module Page 19 10-point perceived exertion scale) causes rapid breathing and increases heart rate substantially (e.g., jogging). For adults (18–65 yr) and older adults (>65 yr), the ACSM recommends a minimum of 30 min of moderate-intensity aerobic activity 5 days per week or 20 min of vigorous-intensity aerobic exercise 3 days per week. They also recommend moderate- to high-intensity (8- to 12-repetition maximum (RM) for adults and 10- to 15-RM for older adults) resistance training for a minimum of 2 nonconsecutive days per week. Balance and flexibility exercises are also suggested for older adults. For substantial health benefits, adults should engage in aerobic exercise at least 150 min per week at a moderate intensity or 75 min per week at a vigorous intensity. In addition, adults and older adults should do muscle-strengthening activities at least 2 days per week. Children should do at least 60 min of physical activity every day. Most of the 60 min per day should be either moderate or vigorous aerobic activity and should include vigorous aerobic activities at least 3 days per week. Part of the 60 min or more of daily physical activity should be muscle strengthening activities (at least 3 days a week) and bone-strengthening activities (at least 3 days a week). The term exercise deficit disorder (EDD) has been used to identify children who do not attain at least 60 min of moderate- to vigorous-intensity physical activity on a daily basis. Children having EDD may be susceptible to pathological processes associated with a physically inactive lifestyle. Improvements in health benefits depend on the volume (i.e., combination of frequency, intensity, and duration) of physical activity. This is known as the dose-response relationship. Because of the dose-response relationship between physical activity and health, the ACSM/CDC physical activity recommendation states that ―persons who wish to improve their personal fitness, reduce their risk for chronic diseases and disabilities, or prevent unhealthy weight gain will likely benefit by exceeding the minimum recommended amount of physical activity‖. Physical Fitness Course Module Page 20 Physical activity lowers the risk of hypokinetic conditions including dying prematurely, coronary artery disease, stroke, type 2 diabetes, metabolic syndrome, high blood lipid profile, cancers (colon, breast, lung, and endometrial), and hip fractures. It also reduces abdominal obesity and feeling of depression and anxiety. Physical activity helps in weight loss, weight maintenance and prevention of weight gain, prevention of fails, and improved functional health, improved cognitive function, increased bone density, and improved quality of sleep. The Exercise and Physical Activity Pyramid illustrates a balanced plan of physical activity and exercise to promote health and to improve physical fitness (see figure 1.2). You should encourage your clients to engage in physical activities around the home and workplace on a daily basis to establish a foundation (base of pyramid) for an active lifestyle. They should perform aerobic activities a minimum of 3 days/wk; they should do weight-resistance exercises and flexibility or balance exercises at least 2 days per week. Recreational sport activities (middle levels of pyramid) are recommended to add variety to the exercise plan. High-intensity training and competitive sport (top of pyramid) require a solid fitness base and proper preparation to prevent injury; most adults should engage in these activities sparingly. Physical Fitness Course Module Page 21  Daily physical activity is the base for physical fitness Try to be active for at least 30 min every day Figure 1.2 The Exercise and Physical Activity Pyramid. Adapted from ―Exercise and Activity Pyramid‖ Metropolitan Life Insurance Company, 1995. Activity 2.1 Dear Student, discuss on the following questions with your partners. 4. What type of relationship exhibited between physical activity and hypokinetic conditions? 5. Describe some of the major physical and mental health benefits of Exercise. 6. How do you plan to exercise a. What is the recommended minimum amount of daily physical activity for health? b. Give examples of moderate-intensity physical activity. 2.2. Physical Activity and Cardiovascular Diseases Physical Fitness Course Module Page 22 According to World Health Organization (WHO, 2011) cardiovascular disease (CVD) caused 17.3 million deaths (30%) worldwide in 2008, and it is projected to cause more than 26 million deaths by 2030. More than 80% of those cardiovascular deaths occurred in low- and middle- income countries. 2.2.1 Coronary Heart Disease (CHD) Globally, coronary heart disease (CHD) accounts for more deaths than any other disease, with more than 7.6 million people dying from it in 2005 (WHO 2007). CHD is caused by a lack of blood supply to the heart muscle (myocardial ischemia) resulting from a progressive, degenerative disorder known as atherosclerosis. Atherosclerosis is an inflammatory process involving a buildup of low-density lipoprotein (LDL) cholesterol, scavenger cells (monocytes), necrotic debris, smooth muscle cells, and fibrous tissue. This is how plaques form in the intima, or inner lining of the medium- and large-sized arteries throughout the cardiovascular system. As more lipids and cells gather in the plaques, they bulge into the arterial lumen. In the heart, these bulging plaques restrict blood flow to the myocardium and may produce angina pectoris, which is a temporary sensation of tightening and heavy pressure in the chest and shoulder region. A myocardial infarction, or heart attack, can occur if a blood clot (thrombus) or ruptured plaque obstructs the coronary blood flow. In this case, blood flow through the coronary arteries is usually reduced by more than 80%. The portion of the myocardium supplied by the obstructed artery may die and eventually be replaced with scar tissue. Coronary Heart Disease Risk Factors: Epidemiological research indicates that many factors are associated with the risk of CHD. The greater the number and severity of risk factors, the greater the probability of CHD. The positive risk factors for CHD are:  Age,  Family History,  Hypercholesterolemia,  Hypertension,  Tobacco use, Physical Fitness Course Module Page 23  Diabetes Mellitus or Prediabetes,  Overweight and Obesity, and  Physical Inactivity. An increased level (≥60 mg・dl–1) of high-density lipoprotein cholesterol, or HDL-cholesterol (HDLC), in the blood decreases CHD risk. If the HDL-C is high, you should subtract one risk factor from the sum of the positive factors when assessing CHD risk. Physical Activity and Coronary Heart: Disease Approximately 6% of CHD deaths worldwide can be attributed to a lack of physical activity (WHO, 2010). Physically active people have lower incidences of myocardial infarction and mortality from CHD and tend to develop CHD at a later age compared to their sedentary counterparts. Individuals who exercise regularly reduce their relative risk of developing CHD by a factor of 1.5 to 2.4. Leading a physically active lifestyle may prevent 20% to 35% of cardiovascular diseases. Physical activity exerts its effect independently of smoking, hypertension, hypercholesterolemia, obesity, diabetes, and family history of CHD. 2.2.2 Hypertension Hypertension, or high blood pressure, is a chronic, persistent elevation of blood pressure that is clinically defined as a systolic pressure ≥140 mmHg or a diastolic pressure ≥90 mmHg. Individuals taking antihypertensive medicine also have this diagnosis. Prehypertension is a term used to describe individuals with a systolic pressure of 120 to 139 mmHg, a diastolic pressure of 80 to 89 mmHg, or both. A clear link exists between hypertension and cardiovascular disease. WHO (2011) identified hypertension as the leading cardiovascular risk factor, attributing 13% of deaths worldwide to high blood pressure. Hypertension is also the primary risk factor for all types of stroke. About 15% to 40% of the global adult population has hypertension. Regular physical activity prevents hypertension and lowers blood pressure in younger and older adults who are normotensive, prehypertensive, or hypertensive. Compared to normotensive individuals, training-induced changes in resting systolic and diastolic blood pressures (5–7 Physical Fitness Course Module Page 24 mmHg) are greater for hypertensive individuals who participate in endurance exercise. However, even modest reductions in blood pressure (2–3 mmHg) by endurance or resistance exercise training decrease CHD risk by 5% to 9%, stroke risk by 8% to14%, and all-cause mortality by 4% in the general population (Pescatello et al. 2004). In a position paper on exercise and hypertension (Pescatello et al. 2004), the ACSM endorsed the following exercise prescription to lower blood pressure in adults with hypertension (see ―ACSM‘s Exercise Prescription for Individuals With Hypertension‖ below). Exercise Prescription for Individuals with Hypertension (ACSM, 2013) Mode: Primarily endurance activities supplemented by resistance exercises Intensity: Moderate-intensity endurance (40–60% VO2R)* and resistance training (60–80% 1- RM) Duration: 30–60 min or more of continuous or accumulated aerobic physical activity per day, and a minimum of one set (8–12 reps) of resistance training exercises for each major muscle group. Frequency: Most, preferably all, days of the week for aerobic exercise; 2 or 3 days/wk for resistance raining. *VO2R is the difference between the maximum and the resting rate of oxygen consumption. 2.2.3 Hyper-cholesterolemia and Dyslipidemia Hypercholesterolemia, is an elevation of total cholesterol (TC) in the blood, is associated with increased risk for CVD. Hypercholesterolemia is also referred to as hyperlipidemia, which is an increase in blood lipid levels; dyslipidemia refers to an abnormal blood lipid profile. Approximately 18% of strokes and 56% of heart attacks are caused by high blood cholesterol (WHO, 2002). Age, gender, family history, alcohol, smoking are risk factors for hypercholesterolemia and regular activity reduced the chance of getting hypercholesterolemia and hyslipidemia. Physical Fitness Course Module Page 25 LDLs, HDLs, and TC: Cholesterol is a waxy, fatlike substance found in all animal products (meats, dairy products, and eggs). The body can make cholesterol in the liver and absorb it from the diet. Cholesterol is essential to the body, and it is used to build cell membranes, to produce sex hormones, and to form bile acids necessary for fat digestion. Lipoproteins are an essential part of the complex transport system that exchanges lipids among the liver, intestine, and peripheral tissues. Lipoproteins are classified by the thickness of the protein shell that surrounds the cholesterol. The four main classes of lipoproteins are chylomicron, derived from the intestinal absorption of triglycerides (TG); very low-density lipoprotein (VLDL), made in the liver for the transport of triglycerides; low-density lipoprotein (LDL), a product of VLDL metabolism that serves as the primary transporter of cholesterol; and high-density lipoprotein (HDL), involved in the reverse transport of cholesterol to the liver. The molecules of LDL are larger than those of HDL and therefore precipitate in the plasma and are actively transported into the vascular walls. Excess LDL-cholesterol (LDL-C) stimulates the formation of plaque on the intima of the coronary arteries. Plaque formation reduces the cross-sectional area and obstructs blood flow in these arteries, eventually producing a myocardial infarction. Therefore, LDL-C values less than 100 mg.dl-1 are considered optimal for reducing CVD and CHD risk. The smaller HDL molecules are suspended in the plasma and protect the body by picking up excess cholesterol from the arterial walls and delivering it to the liver where it is metabolized. Individuals with low HDL-C or high TC levels (dyslipidemia) have a greater risk of heart attack. Those with lower HDL-C (40%) for older (>60 yr) adults than for younger (20–29 yr) adults (7%). Also, the prevalence of metabolic syndrome is much higher for obese (BMI > 30 kg/m2) individuals (~50%) than for normal weight (BMI ≤ 25 kg/m2) individuals (6.2%). Lifestyle must be modified in order to manage metabolic syndrome. The combination of healthy nutrition and increased physical activity is an effective way to increase HDL-C and to reduce blood pressure, body weight, triglycerides, and blood glucose levels. 2.2.7 Aging A sedentary lifestyle and lack of physical activity reduce life expectancy by predisposing the individual to aging-related diseases and by influencing the aging process itself. With aging, a progressive loss of physiological and metabolic functions occurs; however, biological aging may Physical Fitness Course Module Page 29 differ considerably among individuals due to variability in genetic and environmental factors that affect oxidative stress and inflammation. Telomeres are repeated DNA sequences that determine the structure and function of chromosomes. With aging and diseases associated with increased oxidative stress (e.g., CHD, diabetes mellitus, osteoporosis, and heart failure), telomere length decreases. Thus, regular exercise benefits in retarding the aging process and diminishing the risk of aging-related diseases. Activity 2.2 Dear Student, discuss on the following questions with your partners. 1. Define obesity and overweight relative to BMI. 2. Define metabolic syndrome and identify its relationship to CVD. 3. What types of exercise are effective for counteracting bone loss due to aging? Explain how chronic adherence to moderate intensity physical activity affects the aging process. 2.3 Physical Activity and Postural Deformity  What Is Posture? Posture is the position from which movement begins and ends. Having proper postural alignment enables the body to perform movements quicker with less joint and muscular strain.  Why Good Posture Is Important The body is designed to work at the most economical level, thus saving energy for future use. We spend more energy maintaining misaligned posture, which can cause muscle and joint pain. We compromise our body‘s integrity by not maintaining proper posture, resulting in decreased circulation; leading to varicose veins, muscle pain, joint pain, and many other conditions. Physical Fitness Course Module Page 30 Women in general tend to develop poor posture because of many factors. They often have more clerical and computer oriented jobs that require sitting in a chair, eyeing a computer screen for long periods of time. They also wear high-heeled shoes, which lead to an alteration and compensation of their posture. The development of breast tissue or the augmentation of breasts can lead to many postural changes. Women also have less musculature to maintain proper alignment, leading to rounded shoulders, forward head posture, hyper-extended knees, and increased thoracic and lumbar curves. Men can also develop all of these postural problems but at a different degree and rate depending on their situation. To improve your posture and reduce structural damage, you should adhere to a corrective postural exercise program. This simple yet productive program will combat the effects of bad posture and help alleviate joint and muscle pain. Exercises for correcting posture:  Prone Cobra  Axial Extension Trainer  Wall Leans  Cervical Extension using a blood pressure cuff 2.3.1 Musculoskeletal Diseases and Disorders Diseases and disorders of the musculoskeletal system, such as osteoporosis, osteoarthritis, bone fractures, connective tissue tears, and low back syndrome, are also related to physical inactivity and a sedentary lifestyle. Osteoporosis is a disease characterized by the loss of bone mineral content and bone mineral density due to factors such as aging, amenorrhea, malnutrition, menopause, and physical inactivity. It is becoming a major health issue, with an osteoporotic fracture occurring every 3 seconds worldwide. Wrist fractures precede the most common osteoporotic fracture, vertebral fractures. However, hip fractures are the most devastating (International Osteoporosis Foundation 2009). Although osteoporotic fractures may occur in any bone, a hip fracture is recognized as a Physical Fitness Course Module Page 31 surrogate measure of the health care burden and expense due to osteoporosis, especially for men and women ≥50 yr. Osteopenia, or low bone mineral mass, is a precursor to osteoporosis. More than one of every two adults aged 50 or older has either osteoporosis or osteopenia (National Osteoporosis Foundation, 2004). Adequate calcium intake, vitamin D intake, and regular physical activity help counteract age- related bone loss. ACSM suggests the following exercise prescription to help counteract bone loss due to aging and preserve bone health during adulthood. Exercise Prescription for Preserving Bone Health of Adults Mode: Weight-bearing endurance activities (e.g., stair climbing, jogging), activities that involve jumping (e.g., basketball, plyometrics), and resistance training Intensity: Moderate to high, in terms of bone-loading forces Frequency: 3–5 times per week for weight-bearing endurance activities; 2 or 3 times per week for resistance exercise Duration: 30–60 min/day of a combination of weight-bearing endurance activities, activities that involve jumping, and resistance training that targets all major muscle groups Low back pain afflicts millions of people each year. More than 80% of all low back problems are produced by muscular weakness or imbalance caused by a lack of physical activity (see table 1.3). If the muscles are not strong enough to support the vertebral column in proper alignment, poor posture results and low back pain develops. Excessive weight, poor flexibility, and improper lifting habits also contribute to low back problems. While some risks of associated with low back pain are not modifiable, such as gender and age, lifestyle behavior such as smoking, physical inactivity, flexibility, and muscular strength and endurance can all be improved. Because the origin of low back problems is often functional rather than structural, in many cases, the problem can be corrected through an exercise program that develops strength and flexibility in the appropriate muscle groups. Also, people who remain physically active throughout life Physical Fitness Course Module Page 32 retain more bone, ligament, and tendon strength; therefore, they are less prone to bone fractures and connective tissue tears. Activity 2.3 Dear Student, discuss on the following questions with your partners. 1. Explain the relationship between physical inactivity and postural deformity? 2. Describe the relationship between physical inactivity musculoskeletal disorder and low back pain. UNIT SUMMARY  Major chronic diseases associated with a lack of physical activity are CVDs, diabetes, obesity, and musculoskeletal disorders.  Cardiovascular diseases are responsible for 30% of all deaths worldwide.  The positive risk factors for CHD are the following: age, family history, dyslipidemia, hypertension, tobacco use, prediabetes or glucose intolerance, obesity, and physical inactivity.  The prevalence of obesity is on the rise, especially in developed countries; two of every three adults and more than one of every three adolescents and children are overweight or obese. Physical Fitness Course Module Page 33  BMI is used to identify and classify individuals as overweight or obese. Cutoff values for obesity, however, may vary depending on ethnicity.  Metabolic syndrome is a term used to describe individuals who have three or more cardiovascular disease risk factors.  Osteoporosis and low back syndrome are musculoskeletal disorders afflicting millions of people each year.  To benefit health and prevent disease, every adult should accumulate a minimum of 150 min/wk of moderate-intensity physical activity or 75 min/wk of vigorous-intensity physical activity. For additional health benefits, increase physical activity to 300 min/wk and 150 min/wk, respectively, for moderate- and vigorous-intensity exercise. SELF-TEST EXERCISE 1. What diseases are associated with a sedentary lifestyle, and what are the major risk factors for these diseases? 2. What are the benefits of regular physical activity in terms of disease prevention and healthy aging? 3. How does physical activity improve health? 4. How much physical activity is needed for improved health benefits? 5. What kinds of physical activities are suitable for typical people, and how often should they exercise? UNIT THREE MAKING WELL-INFORMED FOOD CHOICES UNIT OBJECTIVES By the end of this unit students should be able to:-  Summarize the basics of nutrition  Define macronutrients and micronutrients  Categorize and describe the body‘s sources of energy Physical Fitness Course Module Page 34   Analyze intake of nutrition and make appropriate changes for sound eating practices  Realize the management of nutrition for better physical performance  INTRODUCTION Regular exercise taxes every cell and every system in your body: your muscles, joints, ligaments, tendons, respiratory, circulatory and immune systems all have to work harder when you exercise. Eating a healthy diet can help minimize the damage caused by exercise and help your body rebuild itself even stronger. Your daily diet needs to meet the tough demands of your training programme as well as keep you healthy. To help you make the right food choices, this unit explains the basis of a good training diet, what each nutrient does, how much you need and how you can achieve your ideal intake. 3.1 Sound Eating Practices  What is Nutrition? And what is Nutrient? Nutrition can be defined as the science of the action of food, beverages, and their components in biological systems. A nutrient is a compound that provides a needed function in the body. Nutrients can be further classified based on the amount needed in the body. Macronutrients are the nutrients the body needs in larger amounts. Micronutrients are also important nutrients, but ones the body needs in smaller amounts. 3.1.1 Macronutrients Carbohydrates: The word carbohydrate literally means "hydrated carbon," or carbon with water. Thus, it is no surprise that carbohydrates are made up of carbon, hydrogen, and oxygen. Sucrose (table sugar) is an example of a commonly consumed carbohydrate. Some dietary examples of carbohydrates are whole-wheat bread, oatmeal, rice, sugary snacks/drinks, and pasta. Physical Fitness Course Module Page 35  Proteins: Like carbohydrates, proteins are comprised of carbon, hydrogen, and oxygen, but they also contain nitrogen. Several dietary sources of proteins include nuts, beans/legumes, skim milk, egg whites, and meat. Lipids: Lipids consist of fatty acids, triglycerides, phospholipids, and sterols (cholesterol). Lipids are also composed of carbon, hydrogen, and oxygen. Some dietary sources of lipids include oils, butter, and egg yolks. Water: Water is made up of hydrogen and oxygen and is the only macronutrient that provides no energy. 3.1.2 Micronutrients Vitamins: These compounds are essential for normal physiologic processes in the body. Minerals: Minerals are the elements (think periodic table) that are essential for normal physiologic processes in the body. Activity 3.1 Dear Student! Try to remember the food you usually consume and list them in the following category of nutrient. Macronutrients Micronutrients 3.1.3 Calories (Food Energy) Food energy is measured in kilocalories (kcals), commonly referred to as calories. Although technically incorrect, this terminology is so familiar that it will be used throughout this course. A kilocalorie is the amount of energy needed to raise 1 kilogram of water 1 degree Celsius. A food‘s kilocalories are determined by putting the food into a bomb calorimeter and determining the energy output: Energy = Measurement of Heat Produced. Below is a picture of a bomb calorimeter and a link to a video showing how one is used. The number of kilocalories per gram for each nutrient is shown below: Physical Fitness Course Module Page 36 Table 3.1:- Amount of calories obtained from nutrients Nutrient Energy (kcal/g) Carbohydrate 4 Protein 4 Lipids 9 Water 0 Vitamins 0 Minerals 0 As the table 3.1 above illustrates, only carbohydrates, protein, and lipids provide energy. However, there is another dietary energy source that is not a nutrient— alcohol. To emphasize, alcohol is not a nutrient, but it does provide 7 kilocalories of energy per gram. Knowing the number of calories in each nutrient allows a person to calculate/estimate the amount of calories contained in any food consumed. Your daily calorie needs will depend on your genetic make-up, age, weight, body composition, your daily activity and your training programme. It is possible to estimate the number of calories you need daily from your body weight (BW) and your level of daily physical activity. Step 1: Estimate your Basal Metabolic Rate (BMR) As a rule of thumb, BMR uses 22 calories for every kg of a woman‘s body weight and 24 calories per kg of a man‘s body weight. Women: BMR = weight in kg x 22 Men: BMR = weight in kg x 24 Step 2: Work out your Physical Activity Level (PAL) This is the ratio of your overall daily energy expenditure to your BMR; a rough measure of your lifestyle activity.  Mostly inactive or sedentary (mainly sitting): 1.2 Physical Fitness Course Module Page 37  Fairly active (include walking and exercise 1–2 x week): 1.3  Moderately active (exercise 2–3 x weekly): 1.4  Active (exercise hard more than 3 x weekly): 1.5  Very active (exercise hard daily): 1.7 Step 3: Multiply your BMR by your PAL to work out your Daily Calorie Needs Daily calorie needs = BMR x PAL This figure gives you a rough idea of your daily calorie requirement to maintain your weight. If you eat fewer calories, you will lose weight; if you eat more then you will gain weight.  Your BMR is the number of calories you burn at rest (to keep your heart beating, your lungs breathing, to maintain your body temperature, etc). It accounts for 60–75% of the calories you burn daily. Generally, men have a higher BMR than women.  Physical activity includes all activities from doing the housework to walking and working out in the gym. The number of calories you burn in any activity depends on your weight, the type of activity and the duration of that activity. Activity 3.2 Dear Student, discuss on the following questions with your partners. 1. Where do you get energy for your body function? 2. How many calories do you need per day? 3. Estimate daily energy needs for an active 60 kg woman and a 70 kg sedentary man. 4. Estimate daily energy needs for an active 60 kg man to gain weight and a 70 kg sedentary woman to lose weight. I. Carbohydrates Carbohydrate is an important fuel for exercise. It is stored as glycogen in your liver and muscles, and must be re-stocked each day. Approximately 100 g glycogen (equivalent to 400 kilocalories) Physical Fitness Course Module Page 38 may be stored in the liver, and up to 400 g glycogen (equivalent to 1600 kilocalories) in muscle cells. The purpose of liver glycogen is to maintain steady blood sugar levels. When blood glucose dips, glycogen in the liver breaks down to release glucose into the bloodstream. The purpose of muscle glycogen is to fuel physical activity. The more active you are, the higher your carbohydrate needs. Guidelines for daily intakes are about 5–7 g per kg of body weight per day for moderate duration/low intensity daily training. Those who do moderate–heavy endurance training should consume 7–10 g per kg body weight per day; and those training more than 4 hours per day are advised to consume 10 g or more per kg body weight per day. To promote post-exercise recovery, the 2003 IOC Consensus conference recommends consuming 1 g per kg BW per hour during the first four hours following exercise. If you plan to train again within 8 hours, it is important to begin refueling as soon as possible after exercise. Moderate and high glycaemic index (GI) carbohydrates will promote faster recovery during this period. However, for recovery periods of 24 hours or longer, the type and timing of carbohydrate intake is less critical, although you should choose nutrient-dense sources wherever possible. Carbohydrates have become, surprisingly, quite controversial. Some people passionately extol the merits of carbohydrates, while others berate them as nutritional assassins. However, it is important to understand that carbohydrates are a diverse group of compounds that have a multitude of effects on bodily functions. Thus, trying to make blanket statements about carbohydrates is not a good idea. During exercise lasting longer than 60 minutes, consuming 20–60 g carbohydrate per hour helps maintain your blood glucose level, delay fatigue and increase your endurance. Choose high GI carbohydrates (e.g. sports drinks, energy gels and energy bars, bananas, fruit bars, cereal or breakfast bars), which convert into blood sugar rapidly. Food manufacturers are always searching for cheaper ways to produce their products. One extremely popular method for reducing costs is the use of high-fructose corn syrup as an alternative to sucrose. High-fructose corn syrup is approximately 50% glucose and 50% fructose, Physical Fitness Course Module Page 39 which is the same as sucrose. Nevertheless, because increased consumption of high-fructose corn syrup has coincided with increased obesity, a lot of controversy surrounds its use. Alternative sweeteners are simply alternatives to sucrose and other mono-and disaccharides that provide sweetness. Activity 3.4 Dear Student, would you list and explain types of carbohydrates and their importance for ordinary person as well as athletes? Please try to illustrate it by providing food examples you most familiar with. II. Protein Protein is another major macronutrient that, like carbohydrates, consists of small repeating units. But instead of sugars, proteins are made up of amino acids. Proteins can be classified as either complete or incomplete. Amino acids from proteins form the building blocks for new tissues and the repair of body cells. They are also used for making enzymes, hormones and antibodies. Protein also provides a (small) fuel source for exercising muscles. Athletes have higher protein requirements than non-active people. Extra protein is needed to compensate for the increased muscle breakdown that occurs during and after intense exercise, as well as to build new muscle cells. The IOC and IAAF both recommend between 1.2 and 1.7 g protein/kg BW/day for athletes or 84–119 g daily for a 70 kg person. This is considerably more than a sedentary person, who requires 0.75 g protein/kg BW daily. Some athletes eat high protein diets in the belief that extra protein leads to increased strength and muscle mass, but this isn‘t true, it is stimulation of muscle tissue through exercise, not extra protein that leads to muscle growth. As protein is found in so many foods, most people, including athletes eat a little more protein than they need. This isn‘t harmful, the excess is broken down into urea (which is excreted) and fuel, which is either used for energy or stored as fat if your calorie intake exceeds your output. Physical Fitness Course Module Page 40 Several studies have found that carbohydrate and protein eaten together immediately after exercise enhances recovery and promotes muscle building. This does not mean additional food or supplements. It means that you should space out some of the protein and carbohydrates you currently have in your diet and consume it after workouts. III. Fat Some fat is essential, it makes up part of the structure of all cell membranes, your brain tissue, nerve sheaths, bone marrow and it cushions your organs. Fat in food also provides essential fatty acids, the fat-soluble vitamins A, D and E, and is an important source of energy for exercise. The IOC does not make a specific fat recommendation, but the American College of Sports Medicine (ACSM) and American Dietetic Association recommend fat provides 20–25% of calorie intake for athletes compared with the UK government recommendation of 33% for the general population. Therefore, about 20–33% of the calories in your diet should come from fat. ‗Bad‘ fats (saturated and trans fats) should be kept to a minimum (the UK government recommends less than 10% of calories), with the majority coming from ‗good‘ (unsaturated) fats. Omega-3s may be particularly beneficial for athletes as they help increase the delivery of oxygen to muscles, improve endurance and may speed recovery, reduce inflammation and joint stiffness. There is neither bad nor good cholesterol, despite the common use of these descriptions in reference to LDL and HDL, respectively. Cholesterol is cholesterol. HDL and LDL contain cholesterol but are actually lipoproteins. It is not necessary to include cholesterol in your diet because our bodies have the ability to synthesize the required amounts. IV. Fiber Physical Fitness Course Module Page 41 The simplest definition of fiber is indigestible matter. Indigestible means that it survives digestion in the small intestine and reaches the large intestine. There are the three major fiber classifications: Dietary fiber: This type of fiber contains both non-digestible carbohydrates and lignin and is always intrinsic and intact in plants. Functional fiber: This type of fiber contains non-digestible carbohydrates only and can be isolated, extracted, or synthesized. Functional fiber can be from plants or animals and produces beneficial physiological effects in humans. Total Fiber: Fiber that contains both dietary fiber and functional fiber. Activity 3.4 Dear Student, discuss briefly on the following questions with your partners. 1. What foods are the best sources of protein? 2. What do protein do for our body? 3. What advantages could you possibly obtain by consuming more fiber foods? 4. Most of the time people are afraid of eating foods constituted with much more fat. Explain why do you think they get threatend by those type of food options. Do you think it is right to afraid and get ride of them? V. Vitamins Vitamins are organic compounds found in foods and are a necessary part of the biochemical reactions in the body. They are involved in a number of processes, including mineral and bone metabolism, and cell and tissue growth, and they act as cofactors for energy metabolism. The B vitamins play the largest role of any vitamins in metabolism. You get most of your vitamins through your diet, although some can be formed from the precursors absorbed during digestion. For example, the body synthesizes vitamin A from the β- carotene in orange vegetables like carrots and sweet potatoes. Vitamins are either fat-soluble or water-soluble. Fat-soluble vitamins A, D, E, and K, are absorbed through the intestinal tract with lipids in chylomicrons. Vitamin D is also synthesized in the skin through exposure to sunlight. Physical Fitness Course Module Page 42 Because they are carried in lipids, fat-soluble vitamins can accumulate in the lipids stored in the body. If excess vitamins are retained in the lipid stores in the body, hypervitaminosis can result. Water-soluble vitamins, including the eight B vitamins and vitamin C, are absorbed with water in the gastrointestinal tract. These vitamins move easily through bodily fluids, which are water based, so they are not stored in the body. Excess water-soluble vitamins are excreted in the urine. Therefore, hypervitaminosis of water-soluble vitamins rarely occurs, except with an excess of vitamin supplements.are stored in the skeleton and necessary for the hardening of bones. Most minerals are ionized, and their ionic forms are used in physiological processes throughout the body. Sodium and chloride ions are electrolytes in the blood and extracellular tissues, and iron ions are critical to the formation of hemoglobin. There are additional trace minerals that are still important to the body‘s functions, but their required quantities are much lower. Like vitamins, minerals can be consumed in toxic quantities (although it is rare). A healthy diet includes most of the minerals your body requires, so supplements and processed foods can add potentially toxic levels of minerals. VI. Minerals Minerals in food are inorganic compounds that work with other nutrients to ensure the body functions properly. Minerals cannot be made in the body; they come from the diet. The amount of minerals in the body is small, only 4 percent of the total body mass and most of that consists of the minerals that the body requires in moderate quantities: potassium, sodium, calcium, phosphorus, magnesium, and chloride. The most common minerals in the body are calcium and phosphorous, both of which are stored in the skeleton and necessary for the hardening of bones. Most minerals are ionized, and their ionic forms are used in physiological processes throughout the body. Sodium and chloride ions are electrolytes in the blood and extracellular tissues, and iron ions are critical to the formation of hemoglobin. There are additional trace minerals that are still important to the body‘s functions, but their required quantities are much lower. Physical Fitness Course Module Page 43 Like vitamins, minerals can be consumed in toxic quantities (although it is rare). A healthy diet includes most of the minerals your body requires, so supplements and processed foods can add potentially toxic levels of minerals. VII. Water You should ensure you are hydrated before starting training competition and aim to minimise dehydration during exercise. Dehydration can result in reduced endurance and strength, and heat related illness. The IOC advises matching your fluid intake to your fluid losses as closely as possible and limiting dehydration to no more than 2% loss of body weight (e.g. a body weight loss of no more than 1.5 kg for a 75 kg person). Additionally, the IAAF cautions against overhydrating yourself before and during exercise, particularly in events lasting longer than 4 hours. Constantly drinking water may dilute your blood so that your sodium levels fall. Although this is quite rare it is potentially fatal. The American College of Sports Medicine advise drinking when you‘re thirsty or drinking only to the point at which you‘re maintaining your weight, not gaining weight. Sports drinks are better than water during intense exercise lasting more than 60 minutes because their sodium content will promote water retention and prevent hyponatraemia. Activity 3.5 Dear Student, discuss briefly on the following questions with your partners. 1. Distinguish between fat – soluble and water – soluble vitamins? which do you think recommendable for better health gain? 2. Which minerals are important for the body if consumed with moderate amount? 3. What is dehydration? How do we prevent yourself from getting dehydrated 3.2 Nutrition and Physical Performance There is universal scientific consensus that diet affects performance. A well-planned eating strategy will help support any training programme, whether you are training for fitness or for Physical Fitness Course Module Page 44 competition; promote efficient recovery between workouts; reduce the risk of illness or overtraining, and help you to achieve your best performance. Of course, everyone has different nutritional needs and there is no single diet that fits all. Some athletes require more calories, protein or vitamins than others; and each sport has its unique nutritional demands. But it is possible to find broad scientific agreement as to what constitutes a healthy diet for sport generally. 3.2.1 Nutrition before Training Exercise What you eat and drink the day before and during the several hours before your workout dictates how much energy you‘ll have for training and how well you will perform. It also affects how much body fat, glycogen or even muscle tissue you burn. Get it wrong and you may find yourself struggling to complete your planned workout and performing under-par. Even worse, you could end up burning muscle rather than fat as your fuel reserves dip. Get your pre-exercise nutrition right and you‘ll have plenty of energy to train hard and perform at your best. Eating the right amount and type of carbohydrate as well as timing your pre-exercise meal correctly will help avoid common problems such as fatigue, dizziness, fainting and stitch.  Why eat before training? The main purpose of your pre-workout meal is to stabilise your blood sugar levels during exercise. It also staves off hunger and minimises the risk of problems such as stitch and hypoglycaemia (low blood sugar levels). But don‘t expect your pre-workout meal to fuel your muscles. There isn‘t enough time for your body to turn the food into glycogen – the muscles‘ main fuel supply – so your body must rely on existing glycogen (and fat) stores. It takes 24 hours to refill muscle glycogen stores, so what you‘ve consumed the previous day matters. For most regular exercisers, a daily diet providing carbohydrates of around 280–350 g for a 70 kg person.  Should you train on empty? It is definitely not advisable to train on an empty stomach, especially if you want to improve strength, endurance or performance. Firstly, you‘re more likely to feel lethargic and unmotivated Physical Fitness Course Module Page 45 when you haven‘t eaten for several hours. Eating a light snack a couple of hours before your workout will reduce the temptation to skip your training. Secondly, when your brain isn‘t getting enough fuel you‘ll feel faint, lose concentration and risk injury. You may become light-headed, weak and shaky – all symptoms of low blood sugar levels – and this will certainly stop you from working out. Finally, you are more likely to fatigue early as muscle glycogen and blood sugar levels dip. Rather like a car running out of petrol, your body will come to a weary halt. You wouldn‘t take your car out on a long journey when the petrol tank is low. So you can‘t expect to exercise very hard or very long when you haven‘t fuelled your body for several hours.  How much to eat before training The exact amount you should eat depends on your body weight (heavier people need more) and how hard and long you plan to exercise (eat more for longer, harder workouts). In general, if you plan to workout for less than 2 hours, aim to eat around 1 g carbohydrate per kg of body weight (or 70 g for a 70 kg person) or 400–600 calories. For longer workouts or endurance events eat around 2 g carbohydrate per kg of body weight (or 600–800 calories). Don‘t eat a big meal just before a workout otherwise you will feel uncomfortable, sluggish and ‗heavy‘.  When to eat before training Ideally, you should aim to have a meal 2–4 hours before a workout. This should leave enough time to partially digest your food although, in practice, the exact timing of your pre-workout meal may depend on your daily schedule. You should feel comfortable neither full nor hungry. According to a study at the University of North Carolina, United States, eating a moderately-high Carbohydrate, low fa