Chapter Four: Becoming Physically

Fit

Basic Concepts

Physical fitnessA set of attributes that people have or achieve

that relates to the ability to perform physical activity

Physical activityAny bodily movement produced by skeletal

muscles that results in energy expenditureExercise (subset of physical activity)

Planned, structured, and repetitive activity designed to improve or maintain physical fitness

Four Components of Physical Fitness

1. Cardiorespiratory endurance Aerobic vs. anaerobic exercise

2. Muscular fitness Strength vs. endurance

3. Flexibility

4. Body composition

Cardiorespiratory Endurance

Ability of the heart, lungs, and blood vessels to process and transport oxygen over a period of time

Produced by exercise involving continuous, repetitive movementsExamples: brisk walking, jogging, cycling

Aerobic (with oxygen) energy productionStructural and functional benefits

Muscular Fitness

Strength: Ability to contract skeletal muscles to a maximal level

Endurance: Ability to contract skeletal muscles repeatedly over a long period of time

Improved by performing repeated contractions at less than maximal levels

Flexibility and Body Composition

Flexibility: Ability of your joints to move through an intended range of motion

Body composition: The make-up of the body in terms of muscle, bone, fat, water, and minerals Fitness experts are most concerned with

percentages of body fat and fat-free weight

Developing a Personalized Fitness Program: Key Principles

• Overload: Placing increasing amounts of stress or resistance on the body causes changes that improve fitness

• Specificity: The type of exercise must be specific to the outcome that is targeted for improvement

• Reversibility (regression): “Use it or lose it”

Physiology

Non-use of muscles leads to quick atrophy

Overuse of muscles leads to lactic acid build up

Chronic overuse leads to oversize issues with muscles and heart

Cardiorespiratory Endurance Training Factors

1. Mode

2. Frequency

3. Intensity

4. Duration

Developing a Cardiorespiratory Endurance Program

1. Mode of activity Continuous activity Using large muscle groups Aerobic in nature Enjoyable Cross-train and/or vary activities to maintain

motivation

Developing a Cardiorespiratory Program

2. Frequency (How often should I train?) 3-5 times/week More than 5 times/week will not create further

improvement Less than 3 times/week will not show significant

improvement

Developing a Cardiorespiratory Program

3. Intensity (How hard should I train?) Target heart rate (THR) = Between 65% and

90% of maximum heart rate Maximum heart rate can be estimated by

subtracting your age from 220

Target heart rate range = (220 – age) x 65-90% Sample calculation for a 20-year-old:

220 - 20 = 200 x 0.65 = 130 bpm

220 - 20 = 200 x 0.90 = 180 bpm

Developing a Cardiorespiratory Program

4. Duration• ACSM recommends 20-60 minutes of

continuous activity• The lower the intensity, the longer the

duration should be

Muscular Fitness

Types of Muscular Fitness Exercises Isometric (“same length”): Muscle contraction

without movement Isotonic (“same tension”): Muscle contraction with

movement against a specific fixed resistance throughout the full range of motion

Isokinetic (“same motion”): Muscle contraction with movement against variable resistance through the full range of motion at a fixed speed

Muscular Fitness: Equipment

Muscular Fitness

Frequency: 2 times/weekOne set of 8-12 repetitions (10-15 repetitions for

adults over 50) of 8-10 exercises Multiple sets could provide greater benefits

Sufficient resistance to fatigue major muscle groups (legs, arms, shoulders, chest, back)

Training recommendations Isotonic or isokinetic exercises Full range of motion at a slow to moderate speed using

rhythmic breathing

Major Muscle Groups

Flexibility

Failure to maintain flexibility can result in reduced range of motion and injury

Two forms of stretching motions: Static stretching: Slow lengthening of a muscle

group to an extended stretch, followed by a hold of the extended position for 10-30 seconds Recommended

Ballistic stretching: A bouncing form of stretching in which a muscle group is lengthened repetitively to produce multiple quick, forceful stretches

Flexibility Training

Stretch all major muscle groups2-3 times/weekShould be done following a warm-upStatic stretching is preferred over ballistic

stretchingHold each stretch for 10-30 seconds

Body Composition

Measurement of percent body fat is often included in a fitness program

To reduce body fat, an exercise program should maximize caloric expenditure ACSM recommends exercise sessions expending

300-400 calories

The Workout Routine

Warm-up (5-10 minutes of slow, gradual, comfortable movements related to the upcoming activity; can end with a period of stretching)

Conditioning (cardiorespiratory endurance, strength training, and/or flexibility workout following ACSM guidelines)

Cooldown (5-10 minutes of relaxing exercises to return the body to a resting state)

Exercise Over the Life Span: Children

Research and recommendations for children’s physical activityU.S. children and teenagers lead very sedentary

livesIncreased percentage of children and teenagers

are overweightNeed at least 60 minutes every day of moderate-

intensity physical activity

Exercise and Aging

Change is gradualIndividual differences occurGreatest change is noted in

areas of complex functionHomeostatic decline occurs

with ageStay physically active to slow

physical decline

Changes in Midlife Adults

Period between 45 and 64 years of age Decrease in bone mass and density Increase in vertebral compression Degenerative changes in joint cartilage Increase in body fat Decrease in capacity to engage in physical work Decrease in visual acuity Decrease in resting energy requirements Decrease in fertility Decrease in sexual function

Changes in Older Adults

Decrease in bone mass and changes in bone structure

Decrease in muscle bulk and strengthDecrease in cardiorespiratory enduranceLoss of nerve cellsDecrease hearing and vision abilitiesDecrease in sensory modalitiesSlower reaction timeGait and postural changes

Exercise for Older Adults

Exercises for younger adults may be inappropriate for people over aged 50

Supervision from a certified instructor may be necessary

Physical exams are recommended before beginning a program

Well-designed programs should start slowly Recognize signs of distress

Special Health Concerns

Low-back painAffects 4 out of 5 adults at least once in their

lifetimesMechanical (postural) problems tend to be the

main culpritRegular physical activity greatly reduces the

occurrences of low-back pain

Special Health Concerns

Female athlete triad

Disordered eating, amenorrhea, and osteoporosis

Signs include: reduced cognitive function, altered hormone levels, early onset of menopause

Early physician referral is vital

Pregnancy Exercise should be

continued barring complications

Avoid overheating, impact exercises, and excessive bouncing or jarring motions

Special Health Concerns

Osteoporosis Decreased bone mass;

may lead to fractures 80% of suffers are

women Lower level of estrogen

may decrease calcium absorption

Adequate calcium and vitamin D intake; weight bearing exercise

Osteoarthritis Joint inflammation Common in older adults Often occurs in weight-

bearing joints Genetic predisposition is

also a key factor Regular physical activity

may reduce the risk for osteoarthritis

Training Recommendations

Drink enough fluid before, during, and after activity

Wear comfortable clothing that promotes temperature regulation

Use appropriate safety equipment

Effects of Steroids

Exercise Injuries: Strategies for Prevention and Care

1. Start at a low level and progress gradually

2. If you stop exercising for an extended time, do not restart at the level at which you stopped

3. Listen to your body

4. Follow rehabilitation instructions carefully

5. Develop a preventive approach to all injuries

Discussion questions. See website