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Section 1

316 Chapter 13

ObjectivesBefore class begins, write the objectiveson the board. Have students copy theobjectives into their notebooks at thestart of class.

Ask several students to share the fitness myths they wrote about.(Possible myths might include that all athletes are fit or that protein supplements build muscle.) Challengestudents to explain why the myths are false.

Teaching Transparency W42

1. Focus

Warm-Up Myth/Fact

The Importance ofPhysical Activity

and HealthPersuasive E-mail

After students read about the benefits ofphysical activity, ask them to write an e-mailto an inactive friend. In the e-mail, they

L3 should try to persuade the friend to getmore exercise by describing the benefits of physical activity. Ask a few students toread their e-mails to the class.

316 Chapter 13

The Importance ofPhysical Activity

Section 1

Objectives� Explain some of the

physical, psychological,and social benefits ofphysical activity.

� Define the fivecomponents of fitness.

� Describe five types ofphysical activity.

Vocabulary• physical activity• endorphins• physical fitness• body composition• aerobic exercise• anaerobic exercise• isometric exercise• isotonic exercise• isokinetic exercise

Myth Being thin is a sign of fitness.

Fact Appearance is not a good indicator ofoverall fitness. Thin people who do not exer-cise are likely to have poor heart, lung, andmuscular fitness.

Identify another fitness mis-conception that teens may hold. Why doyou think they have that misconception?

The Benefits of Physical ActivityHow physically active are you? To answer this question, you first need toknow that physical activity includes more than just sports. Any move-ment that requires your large muscle groups to work is considered

Thus, physical activity includes actions such as walkingbriskly around the mall or doing household chores. Teens should spend60 minutes or more each day performing some form of physical activity.

What happens inside your body when you rake leaves, swim, ordance? The most obvious changes affect your heart, lungs, and muscles.But did you also know that chemical changes occur in your brain thatinfluence your mood? The changes that occur due to physical activityare beneficial to your body, your mind, and your social interactions.

Physical Benefits The physical benefits of exercise extend to manyof the systems in your body.

� Cardiovascular System Your heart and blood vessels receive the mostbenefits from regular physical activity. As your heart becomesstronger, it can pump more blood with less effort. The number of cap-illaries in your muscles increases, which may reduce blood pressure.Exercise also lowers blood cholesterol levels.

� Weight Maintenance Regular physical activity increases your basalmetabolic rate—the amount of energy your body uses when you areat rest. An active metabolism makes it easier to remain at a healthyweight. Staying at a healthy weight can reduce your risk for develop-ing diseases such as diabetes, heart disease, and certain cancers.

physical activity.

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English Language LearnersSum up the benefits of exercise in threesimple sentences: “Exercise keeps youhealthy. Exercise makes you happier.Exercise lets you have fun with others.”

Then ask students to find pictures in magazines that show these benefits. Havethem share their pictures and explain whichsentence(s) each picture represents.

EL

Reading/Note Taking 13-1

Adapted Reading/Note Taking 13-1

The Benefits of Physical Activity

Content Update Use the Web Code toaccess up-to-date information about thehealth benefits of sports. Have studentscomplete the Web activity.

Active LearningOn the board, start a concept map withthe concept “Benefits of PhysicalActivity.” Below that, draw three boxesfor the types of benefits (physical, psy-chological, and social). Call on studentsto go to the board and fill in the boxes.Ask other students to give examples ofspecific benefits of each type.

Building Health SkillsCommunicating Have students make an illustrated poster to persuade otherteens to get 60 minutes of physicalactivity every day. Posters should showseveral benefits of exercise that areespecially important to teens, such asimproved appearance and athletic ability. Arrange for students to displaytheir posters throughout the school.

Sample answer: greaterendurance, weight control,

and fun with friends

Connect to

YOUR LIFE

L3

L2

L3

L2

ELL3

2. Teach


Studies show that

regular physical

activity

also improves

academic

achievement.

For: Updates on the healthbenefits of sports

Visit: www.SciLinks.org/healthWeb Code: ctn-4131

� Bone Strength Your physical activities should include some weight-bearing exercises such as jumping rope or walking. These activitiesmake your bones stronger and denser. Having strong, dense bonesmay reduce your chances of developing osteoporosis later in life.

� Balance and Coordination Physical activity improves your balanceand coordination, which may, in turn, improve your athletic ability.In addition, good balance and coordination can also reduce your riskof injury while performing chores such as climbing ladders or carry-ing packages down stairs.

Psychological Benefits During continuous exercise, your brainreleases chemicals that block pain messages from reachingyour brain cells. Endorphins are also responsible for the feelings of satis-faction and pleasure you feel after a good workout.

People who exercise regularly are likely to be more self-confident andfocused, and have reduced stress levels. Simple stretching exercises, forexample, can relax tense muscles and help you sleep better. If you areupset or depressed, physical activity can help improve your mood. In fact,many health professionals consider physical activity an important part oftreatment for depression.

Social Benefits Exercise is also an opportunity to have fun. Whetheryou play on a sports team or join an aerobics class, physical activity canbe a way to bond with family and friends or build new relationships.

What benefits do you think you gain from regularphysical activity?

Connect to

YOUR LIFE

endorphins,

FIGURE 1 Physical activity can bean opportunity to bond with friendsor meet new people.


318 Chapter 13

Chapter 13, Section 1

The Components of Fitness

Cooperative LearningExplain that many different activities—not just sports or organized activitiessuch as dance classes—can contribute to fitness. Have groups of studentsbrainstorm a wide variety of activitiesto build each component of fitness. (e.g.,inline skating to build cardiorespiratoryendurance; rock-wall climbing to buildmuscular strength) Ask groups to sharetheir ideas.

Active LearningCreate a bulletin board entitled,“Building Components of PhysicalFitness.” Divide the bulletin board intofive columns, and head each columnwith one of the five components of fitness. Ask students to find photos ordraw pictures of activities that buildeach component and post the picturesin the correct columns.

Class DiscussionHelp students distinguish between theconcepts of muscular strength and muscular endurance. Explain that pickingup one heavy rock requires muscularstrength. Picking up hundreds of lightrocks requires muscular endurance.Then ask students to complete thesesentences. You need muscular _______ topush a car 2 feet. (strength) You needmuscular _______ to push a bicycle for 2 miles. (endurance)

Addressing MisconceptionsFitness Is for Athletes Some studentsmight think that only athletes need tobe physically fit. Help students appreciatethe importance of fitness in everydaylife. Ask them to name common dailyactivities (e.g., running up stairs, doingactive chores, playing sports) and identifywhich components of fitness theyinvolve. Discuss how difficult the activitieswould be without adequate levels offitness in those components.

Allow students to answer this question in their

private journals.

Connect to

YOUR LIFE

L3

L1

L2

L3

and HealthConverting Units

Tell the class that Ashley wants to get fourhours of cardiorespiratory exercise eachweek. She plans to swim for 30 minutes,three times a week, and walk briskly for60 minutes, twice a week. Ask: How manyhours per week of cardiorespiratory exer-cise will her plan give her?

L3 (30 min � 3 � 90 min of swimming; 60min � 2 � 120 min of brisk walking; 90min � 120 min � 210 min; 210 min � 60min/hr � 3.5 hr of cardiorespiratory exer-cise each week) How could she modifyher plan to get enough exercise? (Sampleanswer: She could swim four times a weekinstead of three.)

The Components of FitnessMost people do not have the ability to become an Olympic swimmer or aprofessional football player. But, with dedication, just about everyone canbe physically fit. means that you have the energy andstrength to participate in a variety of activities. There are five componentsof fitness: cardiorespiratory endurance, muscular strength, muscularendurance, flexibility, and body composition.

Cardiorespiratory Endurance Cardiorespiratory endurancemeans that your heart, blood vessels, and lungs are able to distributenutrients and oxygen and remove wastes efficiently during prolongedexercise. People with poor cardiorespiratory endurance become short ofbreath and have a very high heart rate after even light exercise. Regularexercise improves cardiorespiratory endurance.

� As the heart muscles become stronger, more blood is pumped witheach beat.

� The lungs become more efficient at delivering oxygen to the bloodand removing carbon dioxide.

Muscular Strength The ability of a muscle to produce force iscalled muscular strength. The amount of weight you can lift is one meas-ure of your muscular strength. Developing muscular strength requiresexerting your muscles for short periods of time, such as doing push-ups.

Muscular Endurance Muscular endurance is the ability of yourmuscles to work for an extended time. How long you can hold a barbell—or how many times you can lift it—is a measure of your muscularendurance. Developing muscular endurance requires repeated actions overan extended period of time, such as raking leaves, rowing, or walking.

Flexibility The ability to move a joint through its entire range ofmotion is called flexibility. This means that you can bend, stretch, andtwist your body easily. Flexibility can vary in different joints. For exam-ple, some people can’t lean over and touch their toes. But their shouldersare flexible enough to help them throw a javelin a great distance.Stretching exercises, if done correctly, can increase flexibility and mayreduce the risk of injury during exercise.

Body Composition Your weight is not the best indicator of yourfitness. In fact, when you begin an exercise program, you may gain someweight as you gain muscle. A better fitness indicator is your body compo-sition. is the amount of fat tissue in your bodycompared to the amount of lean tissue, such as muscles and bones.Having too much, or too little, body fat can lead to health problems.

In which components of fitness are you thestrongest? In which do you need to improve?

Connect to

YOUR LIFE

Body composition

Physical fitness

318 Chapter 13

FIGURE 2 A skinfold test is oneway to estimate body composition.A caliper is used to measure the toplayer of skin and underlying layer offat in different areas of the body.Then the measurements are used toestimate body fat percentage.

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Less Proficient Readers Guide students in relating the informationon physical activities in Figure 3 to theinformation on fitness components onpage 318. Explain how the types of physi-cal activities shown in the figure improveparticular components of fitness described

in the text. For example, point out thatmuscular training activities (in the figure)improve both muscular strength and mus-cular endurance (in the text). Follow thisexample for the other activities and fitnesscomponents.

L2

Visual Learning: Figure 3Teaching Transparency 33Ask students to give examples of otheractivities in each category of the pyra-mid. (e.g., “shooting hoops” for every-day activity, biking for cardiorespiratoryactivity) Ask students to point outwhich everyday activities are also car-diorespiratory, flexibility, or musculartraining activities.Caption Answer Sample answer: deliv-ering newspapers, using stairs insteadof elevators, vacuuming

Building Health SkillsPracticing Healthful BehaviorsChallenge students to create a schedulefor a week’s worth of activities basedon the physical activity pyramid. Urgestudents to follow their schedules forthe week and keep a diary of theiractivities. At the end of the week, askstudents to evaluate their schedules.How could they improve upon theirschedules? How could they change themto better fit their lifestyles? Encouragestudents to create and follow weeklyactivity schedules throughout the school year.

Cooperative LearningSome students may not be familiar with the American names for the many different activities you will talkabout in class. Have student pairs makeflashcards with about ten index cards.On one side of the card they shouldwrite the name of the activity. On theother side they should draw a personparticipating in the activity or equip-ment required for the activity. Havepairs swap cards with other pairs. Then students in each pair can test eachother. The students being tested shouldbe able to name the activity by lookingat the drawing.

EL

L3

L2


Every day

3 to 5 times a week

2 to 5 times a week

A Physical Activity Pyramid

Occasionally

Everyday Activities

• washing the car

• walking the dog

• cleaning your room

• sweeping the garage

• biking to school

Cardiorespiratory

• swimming

• jogging

• dancing

• brisk walking

• rowing

Muscular Training

• weightlifting

• sit-ups

• push-ups

Flexibility

• stretchingexercises

• ballet

• martial arts

Sedentary Activities

• gaming

• watching TV

• “IM-ing”

FIGURE 3 This pyramid can guideyou as you divide your time amongactivities to improve your fitness.Applying Concepts List threeactivities that you would add to theeveryday activities list.


320 Chapter 13

Chapter 13, Section 1

Q: I have been doing sit-ups for months,but my stomach does not look trimmer.What am I doing wrong?

A: Although sit-ups and other abdominalexercises will increase the strength andendurance of your abdominal muscles,these exercises will not necessarily makeyou trimmer. You cannot get rid of fat tissue in a specific area of your body by

“spot training” muscles. The only way toget rid of fat tissue is through exercise andeating a healthy, balanced diet. However, itis important to remember that strongabdominal muscles have many benefits—they help you maintain good posture andreduce strain on your lower back duringeveryday activities.

TEENS Are Asking . . .

320 Chapter 13

Types of Physical ActivityNo single activity can improve or maintain all five components of fitness.Instead, it is important to participate in a variety of physical activities.Physical activities can be classified as aerobic exercise or anaerobicexercise. Strengthening and endurance activities can be further classi-fied as isometric exercise, isotonic exercise, or isokinetic exercise.

Aerobic Exercise Ongoing physical activity that raises your breath-ing rate and heart rate is called (ehr OH bik). Aerobicexercises increase the amount of oxygen that your body takes in and uses.Swimming, running, brisk walking, and cross-country skiing are all formsof aerobic exercise.

By performing aerobic exercise for at least 20 minutes at a time on aregular basis, you can improve your cardiorespiratory endurance. Manyaerobic activities also improve muscular endurance.

Anaerobic Exercise Intense physical activity that lasts for a fewseconds to a few minutes is called (an uh ROH bik).Because anaerobic exercise is so intense and quick, your cardiovascularsystem cannot supply muscles with enough oxygen to produce energy.Unlike your other body cells, muscle cells do not need oxygen to meetthis rapid demand for energy.

Lifting weights, doing push-ups, and sprinting are examples of anaer-obic activities. Most anaerobic exercises develop muscular strength,muscular endurance, or flexibility.

Isometric Exercise Place your palms together and push themagainst each other. This is an (eye suh MET rik), anexercise in which muscles contract but very little body movement takesplace. If you do isometric exercises on a regular basis, the muscles youuse will become stronger.

isometric exercise

anaerobic exercise

aerobic exercise

FIGURE 4 To be truly physicallyfit, you should participate in avariety of activities so that yourmuscles are worked in differentways. Classifying Whichcomponents of fitness do each of these activities improve?

Aerobic Exercise Anaerobic Exercise

Types of Physical Activity

Building VocabularyDefine an- (not) and aerobic (using oxygen). Then, ask: Based on these definitions, what does anaerobic mean?(not using oxygen) Have students readthe definitions of aerobic and anaerobicexercise on this page. Relate the twodefinitions by explaining that anaerobicexercise is work produced by musclecells without using oxygen for energy.

Visual Learning: Figure 4Have students examine the photos andanswer the caption question. Call on astudent to read his or her answer.Discuss the fact that many activitiesimprove more than one component offitness. For example, swimmingimproves muscular strength andendurance as well as cardiorespiratoryendurance. Ask students to identifyother examples.Caption Answer aerobic exercise—cardiorespiratory endurance, muscularendurance; anaerobic exercise—muscularstrength and endurance, flexibility; isometric exercise—muscular strength;isotonic exercise—muscular strengthand endurance; isokinetic exercise—muscular strength

Cultural ConnectionHelp your class expand their knowledgeof different types of physical activities.Invite students to discuss active pastimes,such as a dance or a game, that areunique to their cultures. Also ask otherteachers if they would share examplesof active pastimes from their cultures.Invite the students and teachers todemonstrate or explain the activity tothe class. Ask students to comment onthe activity in their private journals. Is this activity something they couldintegrate into their personal fitness program?

L3

L3

L2



1. movement that works large musclegroups; sample answer: walking the dog, ballet, sit-ups

2. physical: cardiovascular health, weightmaintenance, bone strength, balance andcoordination; psychological: self-confidence,less stress, better mood; social: bondingwith family, making new friends

3. cardiorespiratory endurance: ability of cardiorespiratory system to deliver enoughoxygen; muscular strength: ability to produce force; muscular endurance: howlong muscles can work; flexibility: howwell joints move through their range ofmotion; body composition: amount of fattissue compared to lean tissue

4. aerobic (running), anaerobic (push-ups), isometric (push palmstogether), isotonic (pull-ups), isokinetic (therapy machines)

5. Anaerobic exercise is so intense thatthe cardiovascular system cannotsupply muscles with enough oxygen.

6. Aerobic exercise: Increasedbreathing and heart rates supplycells with more oxygen. Anaerobicexercise: Muscle cells produce burstsof energy without oxygen.

7. Golf should be listed last, but theother sports may be listed in anyorder that can be justified.

8. by explaining the benefits of exercise

Exercise Classes If there is a localcommunity center, it may have low-cost classes. Charts and posters shouldinclude information on locations,phone numbers, and times of classes.Arrange for students to display theirwork at school.

Health and Community


Isotonic Exercise (eye suh TAHN ik) involves con-tracting and relaxing your muscles through the full range of a joint’smotion. Pull-ups are an example of isotonic exercise. Exercises with freeweights, such as barbells, are also isotonic. Through repetition of isotonicexercises, you can develop muscular strength and endurance.

Isokinetic Exercise In (eye soh ki NET ik) mus-cles contract at a constant rate. Isokinetic exercises require fitnessmachines that provide resistance to muscle movement. These exercisesare often used as therapy to rebuild muscle strength after an injury.

isokinetic exercise

Isotonic exercise

Section 1 Review

Key Ideas and Vocabulary 1. Define the term physical activity. List three

physical activities that are not sports.

2. List four physical benefits of regular physicalactivity. Then list three psychological benefits andtwo social benefits.

3. Briefly explain the five components of fitness.

4. List the five types of physical activity and give anexample of each.

5. Explain why muscles do not use oxygen to produceenergy during anaerobic exercise.

Critical Thinking 6. Comparing and Contrasting Explain how aerobic

exercise differs from anaerobic exercise.

7. Sequencing Put the following activities in orderfrom the one that would contribute the most tocardiorespiratory endurance to the one that wouldcontribute the least: golf, basketball, tennis,volleyball. Explain your order.

8. Applying Concepts How would you convince afriend to start an exercise program?

CommunityHealth and

Exercise Classes Contact local communitygroups, fitness centers, or universities to find freeor low-cost exercise classes that are open to thepublic. Summarize the information in a chart orposter to display at your school.

Isometric Exercise Isotonic Exercise

Isokinetic Exercise

Section 1 Review

EvaluateThese assignments can help you assessstudents’ mastery of the section content.

Section 1 ReviewAnswers appear below.

Teaching Resources• Practice 13-1• Section 13-1 Quiz

Reteach

Side by side on the board, write theheadings Components of Fitness andTypes of Physical Activity. Call on onestudent after another to list an itemunder the appropriate heading untilboth lists are complete. Call on otherstudents to draw arrows matching eachcomponent of fitness with a type ofactivity that helps build it.

Enrich

Teaching Resources• Enrich 13-1

L4

L2

3. Assess

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