This is an excerpt from Fitness for Life: Middle School-2nd Edition by Charles B. Corbin,Guy Le Masurier & Dolly D. Lambdin.
Physical activity occurs when your muscles contract to make your body move. The national physical activity guidelines for teens recommend at least 60 minutes, and up to several hours, of physical activity each day of the week. The guidelines recommend that teens perform a variety of activities. There are five basic types of physical activity from which you can choose to meet the national activity recommendation for youth. In this book the Physical Activity Pyramid for Teens is used to illustrate each of the different types of activities (see figure 1.2).
Figure 1.2 The Physical Activity Pyramid for Teens includes many types of activities.
© Charles Corbin
How Do I Know if I Am Active Enough?
In general you are active enough for good health if you meet the national teen guideline of 60 minutes or more of physical activity per day. However, the guidelines indicate that you should do a variety of activities and include some vigorous physical activity and some activity for building muscle fitness and for building strong bones. If you perform a variety of activities from the Physical Activity Pyramid you will meet the national guidelines. In the paragraphs that follow you will learn more about the pyramid.
There is a popular saying that "a picture is worth a thousand words." The saying means remembering a picture may be better than trying to remember a lot of words. So in this book the Physical Activity Pyramid picture is used to help you remember the five types of physical activity. Activities such as moderate physical activity are placed at the wide base of the pyramid because they typically are performed more regularly by people than activities higher in the pyramid. Activities at the bottom typically need to be performed more often than those higher in the pyramid to get benefits. The pyramid also has a triangle at the top that helps you remember the need for energy balance. Energy balance means expending as many calories in physical activity as the calories you consume in food. To get fitness, health, wellness, and energy balance you should choose activities from each of the five steps of the pyramid. You can combine activities from all five steps to meet the daily activity recommendation.
The first step in the pyramid includes moderate physical activities. The intensity of moderate activities is not too easy and not too hard. Any activity that is about as intense as walking briskly is considered moderate. One reason why moderate activities are placed at the bottom of the pyramid is that more people do moderate activity than any other type of activity. Moderate activities are also placed at the wide base of the pyramid because you get the best results when you do them on all or most days of the week. Activities at higher steps in the pyramid can be done less frequently and still provide important benefits.
Many moderate activities are sometimes referred to as lifestyle activities because you do them as part of your daily life. Examples include walking to school, working around the house, and working in the yard. Experts recommend that adults do moderate physical activity for 30 minutes or more each day. This is because activities from step 1 of the Physical Activity Pyramid help people reduce their risk of disease and help them maintain a healthy body weight. Some moderate activities are called lifetime activities because you can do them when you’re young as well as when you grow older. Some activities from other steps of the pyramid are also considered to be lifetime activities. Examples include sports such as bowling and golf and recreational activities such as fishing because they’re moderate in intensity. As you’ll learn later in this book, it’s recommended that teens do regular moderate activity to develop activity habits that can be used throughout life.
Vigorous aerobics is included in the second step of the Physical Activity Pyramid. Vigorous aerobics is a type of vigorous physical activity that is especially good for building cardiorespiratory endurance. The word aerobic means "with oxygen." In aerobic activities, your body supplies oxygen to keep you going. When your heart beats faster than normal during vigorous aerobics, your heart supplies your body with the oxygen it needs to keep going. Vigorous aerobics is the most popular type of vigorous physical activity for people of all ages. Examples of vigorous aerobics are running, swimming, in-line skating, aerobic dance, and biking at a vigorous intensity.
Vigorous sports and vigorous recreation at the third step of the pyramid also require your heart to beat faster and require you to breathe faster than normal. When done for at least 20 minutes at a time at least three days a week, these activities build cardiorespiratory endurance and provide health benefits similar to those provided by vigorous aerobics. Examples of vigorous sports are tennis, basketball, badminton, volleyball, and soccer. Examples of vigorous recreation are hiking, backpacking, and biking.
The word vigorous is used in combination with the terms aerobics, sports, and recreation when describing activities at the second and third steps of the pyramid to make it clear that activities at these steps are more intense than moderate activities. Moderate physical activities at the first step of the pyramid are also considered to be aerobic because your body can supply enough oxygen to allow you to keep doing these activities for long periods of time. But they’re not considered to be vigorous because they’re not intense enough to build optimal levels of cardiorespiratory endurance.
Exercise is a word used to refer to physical activity that is done with the specific purpose of building physical fitness. Muscle fitness exercises are included in the fourth step of the Physical Activity Pyramid for Teens. Muscle fitness exercises are designed to build all three parts of muscle fitness including strength, muscular endurance, and power. One reason why this type of exercise is placed higher in the pyramid than other types is that these exercises need not be performed every day to get benefits. Experts recommend that teens do muscle fitness exercises (such as curl-ups and push-ups) at least two days a week. Muscle fitness exercises help you to build strong bones, prevent muscle injury, and gain many of the same health benefits as with activities from steps 1 through 3.
Flexibility exercises build flexibility and help you to perform well in daily life activities and sport. They may also help reduce risk of injury. They are placed at step 5 of the pyramid. While they can be performed daily, you can maintain flexibility by performing them on two or three days per week.
At the very top of the pyramid is a balance scale. This scale helps show the importance of energy balance. As noted earlier in this lesson, energy balance means that the calories in the food you eat each day are equal to the calories you expend in exercise each day. You must achieve energy balance in order to maintain a healthy body composition. Activities from all steps of the pyramid expend energy and help you balance energy.
At the bottom of the teen physical pyramid are two small pictures with big cross marks over them. One picture is of a video game controller and the other is a picture of a television set. The pictures are meant to caution against being inactive. Being inactive or sedentary isn’t good for your health or fitness. It can also limit your productivity in school and in performing other important daily tasks. This does not mean that you should never play video games or watch television. The pictures are meant to indicate that it is good to limit screen time and to avoid being sedentary.
Inactivity, as used in the pyramid, doesn’t include productive rest, such as sleep that allows recovery from the day’s activities. For example, teens need at least 9 hours of sleep each day. As a teen you also need time for relaxation and productive light activities, such as reading and doing homework.
As noted earlier, to get all of the many benefits of physical activity, teens need to do 60 minutes of daily activity. Ideally you will do activities from each of the five steps each week. You will learn more about the formula for getting optimal benefits in later chapters of this book.
Do You Sit Too Much?
Many teens spend more time watching TV and playing computer games than they do in school. Each day, you should spend at least as much time in moderate or vigorous activity as you do watching TV or playing inactive games.
Learn more about Fitness for Life: Middle School, Second Edition.