PHYSICAL DEVELOPMENT
An Overview
Developed by: Yvette Sparks and Mike Todd
First Developed: December, 1997
Citation: Sparks, Y., & Todd, M. (1997). Physical development: An overview. Educational Psychology Interactive. Valdosta, GA: Valdosta State University. Retrieved [date], from http://www.edpsycinteractive.org/topics/physical-biology/physical.html
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The word physical means different things to different people. Some people look at the term "physical" as simply everything related to anatomy and physiology. Others believe that the word "physical" has to do with health and fitness components related to the body. And still others believe that "physical" corresponds with wellness. Although all of these definitions fit the word physical, the most popular view is that of wellness (Insel, Roth, Rollins & Petersen, 1996). In Health and Wellness (1996), Edlin, Golanty & Bum defined wellness as emphasis placed on individual responsibility for well-being through the practice of health-promoting lifestyle behaviors. Having good wellness involves being free of illness and disease (as often as possible), having viability (being able to live actively, energetically, and fully), and being in good spirits most of the time.
Human beings were designed for physical or bodily activity. Regular physical activity is a positive health habit and is vital to the overall wellness for the individual. The sedentary lifestyle produced by most occupations does not provide adequate physical labor. The homemaker, secretary, teacher, salesperson, and attorney have hectic, stressful lives but they often fail to engage in the vigorous activity needed to be physically fit. We must all learn to make intelligent decisions about lifetime health and physical fitness that includes planning daily vigorous exercise.
Americans desperately lack adequate physical fitness and suffer from lifestyle diseases called hypokinetic diseases. These conditions, caused by underactivity, include coronary heart disease, cancer, osteoporosis, diabetes, and obesity. In the United States, approximately 250,000 premature deaths every year can be attributed to lack of exercise (Pate, Russell, et. al. 1995). According to Dr. Steven Blair, epidemiologist for the Cooper Institute for Aerobics Research, a sedentary lifestyle is as much a risk factor for disease as is high blood pressure, obesity, and smoking (Powell, Blair 1994). The college student shows early symptoms of hypokinetic disease through low levels of energy and creeping obesity. Can you relate to any of these warning signs? It is known that you reach the peak of your natural fitness during the late teens to early twenties and, unless you maintain physical activity, the body deteriorates and ages even more quickly.
Alarming headlines such as "Americans are fatter than ever," "The number of expanding Americans is expanding," and "Are Americans the fattest people in the world?" are cause for concern. Apparently, American waistlines are growing. In the last ten years, American adults have shown an average weight gain of nearly eight pounds per person (Kuczmarski et. al., 1994). Some studies show that a third of Americans are overweight (Kuczmarski). What is the cause of this national problem? Experts place the blame on too many calories consumed and, more significantly, on not enough calories expended in exercise. The situation is compounded by the number of energy-saving devices Americans use--and the list grows yearly (electric garage door openers, TV remotes, computers, riding lawn mowers, electric car windows, snowblowers, leaf blowers). The amount of energy the average American expended even a decade ago is enormous compared to what we expend in the 1990s.
Even more appalling, ongoing research shows there is a youth fitness crisis. Our nation’s children have increased risk of heart disease--too much body fat, elevated blood pressure, high cholesterol, and poor fitness--caused by lack of exercise. Several studies have shown that a full third of our nation’s youth are not physically active enough for aerobic benefit (Bar-Or, 1987; Ignico, 1990). They also weigh more and have more body fat than twenty years ago (JOPHERD, 1987; Bar-Or). If things do not change, our nation’s most precious asset, the adults of tomorrow, will likely contribute to future heart disease and cancer statistics. The National Coalition for Promoting Physical Fitness is an excellent resource for current information related to physical fitness.
Attaining Wellness
An often asked question is "How does a person attain wellness?" Unfortunately, at least for most of those who ask this question, one cannot just attain wellness. Wellness is ongoing and needs to be a lifestyle a person chooses. It is not and end result, but rather a process by which an individual takes control of the way they live through developing every aspect of the body, mind, and emotions in order to produce and keep equilibrium in one’s life. Physical Wellness can be defined as choosing and maintaining healthy habits pertaining to the body. Healthy habits include such things as: 1) eating well, 2) exercising regularly, 3) responsible decisions about sex, 4) routine medical examinations, and 5) staying free of injury and disease. For a person to maintain a high level of Physical Wellness he/she should understand the principles related to these five areas of health.
Physical fitness is multifaceted and involves both skill-related and health-related components. The skill-related components of fitness (speed, power, agility, balance, reaction time, and coordination) are primarily important in achieving success in athletics and are not as crucial for the development of better health. The five health-related components of physical fitness are cardiorespiratory endurance, muscular strength, muscular endurance, flexibility, body composition and nutrition.
Probably the most important fitness component is cardiorespiratory endurance (CRE). It is the ability to deliver essential nutrients, especially oxygen, to the working muscles of the body and to remove waste products during prolonged physical exertion. It involves the efficient functioning of the heart, blood vessels, and lungs. Vigorous exercise improves the functioning of the cardiorespiratory system and is directly related to reduced coronary risk. The American Medical Association states that exercise is the most significant factor contributing to the health of the individual (Blair, Kohl, Paffenbarger, Clark, Cooper & Gibbons, 1989).
When levels of cardiorespiratory fitness are low, the heart has to work very hard during normal daily activities and may not be able to work hard enough to sustain high-intensity physical activity in an emergency. As cardiorespiratory fitness improves, the heart begins to function more efficiently. It doesn’t have to work as hard at rest or during low levels of exercise. The heart pumps more blood per heartbeat, resting heart rate slows down, blood volume increases, blood supply to the tissues improves, the body is better able to cool itself, and resting blood pressure decreases. A healthy heart can better withstand the strains of everyday life, the stress of occasional emergencies, and the wear and tear of time. Cardiorespiratory endurance training also improves the functioning of the muscles and liver which enhances the body’s ability to use energy supplied by food.
Cardiorespiratory endurance is considered the most important component of health-related fitness because the functioning of the heart and lungs is so essential to overall wellness. A person simply cannot live very long or very well without a healthy heart. Low levels of cardiorespiratory fitness are linked with heart disease, the leading cause of death in the United States. Cardiorespiratory endurance is developed by activities that involve continuous rhythmic movements of large muscle groups like those in the legs – for example, walking, jogging, cycling, and aerobic dance.
Muscular strength is the amount of force a muscle can produce with a single maximum effort. It is characterized by activities of short duration at high intensity. Lifting a heavy object such as a suitcase or 100-pound weight one time are examples. Strong muscles are important for the smooth and easy performance of everyday activities, such as carrying groceries, lifting boxes, and climbing stairs, as well as for emergency situations. They help keep the skeleton in proper alignment, preventing back and leg pain and providing the support necessary for good posture. Muscular strength has obvious importance in recreational activities. Strong people can hit a tennis ball harder, kick a soccer a ball farther, and ride a bicycle uphill more easily.
Muscle tissue is an important element of overall body composition. Greater muscle mass (or lean body mass) makes possible a higher rate of metabolism and faster energy use. Maintaining strength and muscle mass is vital for healthy aging because muscular strength and endurance tend to decline with age. This loss can be delayed and strength can be maintained by participating in a strength program. Muscular strength can be developed by training with weights or by using the weight of the body for resistance during calisthenic exercises such as push-ups or sit-ups. Many people have joined health clubs and are enjoying the benefits of using weight equipment such as Universal, Nautilus, and Cybex. The result is a better physical appearance and greater efficiency in both everyday activities and sudden emergencies.
Muscular endurance is the ability to sustain a given level of muscle tension – that is, to hold a muscle contraction for a long period of time, or to contract a muscle over and over again. It is characterized by activities of long duration but low intensity. Muscular endurance is important for good posture and for injury prevention. For example, if abdominal and back muscles are not strong enough to hold the spine correctly, the chances of lower-back pain and back injury are increased. Muscular endurance helps people cope with the physical demands of everyday life and enhances performance in sports and work. It is also important for most leisure and fitness activities. Like muscular strength, muscular endurance is developed by stressing the muscles with a greater load (weight) than they are used to. The degree to which strength or endurance develops depends on the type and amount of stress that is applied. Examples of muscular endurance are performing repetitions of push-ups, sit-ups, or chin ups. Strength and endurance are essential in everyday activities such as housework, yard work, and recreational sports.
Flexibility is the ability to move body joints through a full range of motion (ROM). By experimenting with your own body, you can immediately tell that joints can be moved to different degrees of motion and that they do not all move in the same way. There are four major joints in the body and each joint because of their limitations move body parts differently. These four joints are fixed, pivot, hinge, and ball and socket. Limitations of ROM in a joint is due to the bony structure holding the joint together and the soft tissue surrounding the particular joint. Three examples of soft tissue that effects flexibility are muscles (meaty tissue surrounding bone), tendons (connect muscle to bone), and ligaments (connect bone to bone).
Benefits of having good flexibility are numerous and increase the quality of life for many people, especially the elderly. There is a saying that goes something like, "Use it or lose it!" Many of us have seen senior citizens that walk "hunched" over and some with canes to aid in walking. Most of the time, members of the older population have to walk this way because they have gradually lost flexibility over the years. If an individual wants to reduce injury, inhibit lower back pain, prevent post-exercise pain, and relieve emotional tension that person will work on attaining adequate flexibility.
There are some basic stretching techniques and flexibility exercises a person can employ to obtain good flexibility. These techniques are static (slowly move muscle to mild tension and hold for 8-15 seconds), dynamic (same positions as static but movement is continuous) and partner assisted (partner helps hold position during stretch). For a person to attain adequate flexibility through the use of these techniques, Williams, Harageones, Johnson & Smith (1988) recommend to participate in a stretching program with a frequency of at least three days a week, at a intensity level of mild tension on the muscle, and holding stretches (static) between 8-15 seconds.
Body composition refers to the amount of fat in proportion to lean body tissue (muscle, bone, and water). The ratio between body fat and fat-free weight is a better gauge of fatness than is body weight. There are various ways to measure body composition: body mass index, skinfold calipers, bioelectrical impedance, and hydrostatic underwater weighing technique. The ratio between body fat and lean body tissue is a better gauge of fatness than is body weight measured by use of a scale or height/weight chart method. For instance, a height /weight chart may label a 6-foot, 210-pound football player as overweight, when in reality he has only 10 percent body fat, as measured with skinfold calipers. On the other hand, someone who looks good in her size eight jeans may have 32 percent body fat. The best advice is to have your body composition analyzed by a professional. Obesity is not only unhealthy and uncomfortable, it is associated with increased risk for heart disease, diabetes, high blood pressure, cancer, gallbladder disease, and joint and lower back problems.
Healthy body composition involves a high proportion of lean body tissue and an acceptably low level of body fat, adjusted for age and gender. A person with excessive body fat is more likely to experience a variety of health problems. The best way to lose fat is through a lifestyle that includes a sensible diet and exercise. The best way to add lean body tissue is through weight training, also know as strength or resistance training.
Scientifically, nutrition is the study of food and how the body uses food in health and disease. But in terms that may be better understood, nutrition can be described in three words: 1) Variety, 2) Balance, and 3) Moderation. Choosing to eat a balanced diet by consuming a variety of foods, while keeping serving sizes and intake of fats, salts, and sugars moderate will help a person obtain a higher level of wellness and fight against disease. Fortunately for us there is a food table and dietary guidelines we can use that will enable us to eat correctly no matter how big, small, young, or old we might be. The table is called The Food Guide Pyramid and was developed by the U.S. Department of Agriculture. Now, here is the unfortunate part. A better understanding is needed by consumers in four areas of nutrition. These areas are essential nutrients, recommended daily allowances (RDA), nutrient supplement intake, and the dietary guidelines.
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