exercise physiology & fitness

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Copyright © 2012 by The McGraw-Hill Companies, Inc. All rights reserved.McGraw-Hill/Irwin

CHAPTER 7

Exercise Physiology & Fitness

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Exercise Physiology & Fitness

What is exercise physiology?

What is the role of physical activity and exercise in achieving physical fitness and health?

How do you use the FITT formula to design a fitness program?

What are the contributors and deterrents to fitness?

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Exercise Physiology

The study of the effects of exercise on the body.

Body’s responses and adaptations to different exercises: System to subcellular level Acute (short term) to chronic

(long term) adaptations

Population served: Elite performer People of all ages and

abilities

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Historical Development

Late 1800s - the use of anthropometry to measure changes in students’ development after training programs.

Early 1900s – McKenzie ~ Investigating effects of exercise on various systems of the body and the idea of preventative medicine.

After WWII - increased interest in fitness as a result of youth fitness tests and the results of the physicals of men in the military.

1968 – Dr. Kenneth H. Cooper promotes aerobic exercise and its contribution to health; publishes Aerobics.

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Historical Development

1974: ACSM: Guidelines for Graded Exercise Testing and Prescription.

1980s and 1990s: Increased understanding of the relationship between physical activity and health. 1996:Surgeon General’s Report Physical Activity &

Health

2000: 1st certification exams for Clinical Exercise Physiologists.

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Areas of Study

Effects of various exercises on various systems of the body.

Relationship of energy metabolism to performance.

Effects of environmental factors on performance.

Effects of individual differences

Effectiveness of various rehabilitation programs.

Ergogenic aids and exercise.

Health and therapeutic effects associated with exercise.

Effects of nutrition on performance.

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Specialization

EXERCISE PHYSIOLOGY – EMERGING FIELDS OF STUDY

Cardiac Rehabilitation

Focuses on the assessments of cardiovascular functioning and on the effectiveness of various exercise programs in preventing cardiovascular disease and rehabilitating individuals suffering from the disease.

Exercise Biochemistry

Examines the effects of exercise at the cellular level, specifically within the muscle cell.

Exercise Epidemiology

Studies the relationship between physical activity and mortality.

Pediatric Exercise Studies the response of the body to exercise during childhood, including the effects of growth and maturation and how responses differ between children and adults.

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Physical Fitness

Ability of the body’s systems to function efficiently and effectively.

Individuals who are “physically fit” have the ability to: “carry out daily tasks with

vigor and alertness, without undue fatigue, and with ample energy to enjoy leisure-time pursuits and to meet unforeseen emergencies.”

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Physical Fitness

Health Fitness Body composition

Cardiorespiratory endurance

Flexibility

Muscular endurance

Muscular strength

Performance Fitness Agility

Balance

Coordination

Speed

Reaction Time

Power

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Physical Activity and Health

Chronic Diseases Major threat to health

today

Hypokinetic Diseases Diseases caused by

insufficient physical activity, often in conjunction with inappropriate dietary practices.

Coronary heart disease, hypertension, osteoporosis, non-insulin diabetes, chronic back pain, and obesity

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Physical Inactivity & Health

Inactivity is a risk factor for several diseases.

Individuals who lead a sedentary lifestyle have increased risk of morbidity and mortality. Inactive individuals have almost twice the risk of

CHD as those who are active.

The degree of risk is similar to cigarette smoking, hypertension, and obesity.

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Dose-response Debate

What kind of activity?

How much time spent in activity?

At what intensity should it be performed?

How often in order to see benefits?

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Consensus Statement

Recommended that adults engage in 150 minutes of moderate-intensity or 75 minutes of vigorous-intensity physical activity per week.

Recommended that adults engage in muscle-strengthening exercises on 2 or more days a week that work all the major muscle groups. Additional benefits can be derived from increasing the amount and/or intensity of physial activity.

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Health Benefits

Enhanced cardiovascular function, including reduction of many cardiovascular disease risk factors.

Increased ability to perform tasks of daily living.

Reduced risk of muscle and joint injury.

Improved work performance.

Improved physical appearance, self-image, and sound mental health.

Reduction of susceptibility to depression and anxiety

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Health Benefits

Management of stress.

Increased socialization through participation in physical activities.

Improved overall general motor performance.

Increased energy.

Resistance to fatigue.

Mitigate the debilitating effects of old-age or retain a more desirable level of health for a longer period of time.

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Energy Production for PA

Two ways to produce ATP (adenosine triphosphate) as energy to perform muscular activity:Anaerobic system

Without oxygen High energy expenditure, short time (6-60 seconds)

Aerobic system With oxygen Lower rate of energy expenditure, longer period of

time (more than 3 minutes)

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Principles of Fitness Training

Principle of Overload To gain improvements in health and fitness, an

increased workload must be placed on the body.

Principle of Specificity Training must occur with the specific muscle or

body part the person is attempting to improve.

Principle of Progression Overload should be applied gradually, and steadily

increased as the body adapts.

Principle of Diminishing Returns As fitness increases, gains achieved become less

and less as individuals approach limits of adaptability.

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Principles of Fitness Training

Principle of Variation Helps maintain individuals’ interest and provides a change of

pace while continuing to make progress toward desired goals.

Principle of Reversibility “Use it or lose it” – inactivity leads to gradual erosion of

benefits achieved.

Principle of Individuality Individuals respond differently to exercise and will vary in

their rate of improvement and levels of achievement.

Principle of Recovery Rest allows the body to recover and adapt to the changes

placed on it.

Principles of Safety Safety is paramount.

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Planning a Fitness Program

Threshold of Training Minimal level of exercise

needed to achieve desired benefits.

Target Zone Defines the upper limits

of training and the optimal level of exercise.

Needs and goals of the individual Program should meet the

goals of the individual.

FITT Formula

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FITT Formula

Frequency Number of sessions each

week (i.e., how often).

Intensity Degree of effort put forth

during exercise (i.e., how hard).

Time Duration of activity (i.e.,

how long).

Type Mode of exercise being

performed.

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Cardiorespiratory Endurance

Body’s ability to deliver oxygen effectively to the working muscles to perform physical activity.

Most important component of health fitness.

Helps prevent hypokinetic disease.

Concerned with the aerobic efficiency of the body.

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Cardiorespiratory Endurance

FITT Formula

Frequency: 3 to 5 times per week

Intensity: 55% - 90% HRMAX or 40% - 85% HRR

Time: 20 - 60 minutes

Type: Aerobic activities

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Target Heart Rate Zone

HRMAX= 220 bpm – age

Target zone = 55% to 90% HRMAX

Lower threshold target HR= HRMAX x 55%

Upper threshold target HR= HRMAX x 90%

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Body Composition

Percentage of body weight composed of fat as compared with fat-free or lean tissue.

Obesity is associated with numerous health problems and earlier mortality.

Determination of the cause of obesity is important.

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Body Composition

Body composition is influenced by nutrition and physical activity.

Energy balance is important to achieving a favorable body composition.

Energy expenditure through: basal metabolism (maintenance of essential life

functions) work (including exercise) excretion of body wastes

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Body Mass Index

Estimated – Weight in pounds

X 703 divided by height in inches squared

Often used in large scale surveys because of ease of collecting large amounts of data.

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Energy Balance

Number of calories taken into the body as food minus number of calories expended.

Caloric Expenditure: Neutral balance

Caloric intake equals expenditure.

Positive balance More calories consumed than expended.

Negative balance More calories are expended than consumed.

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Body Composition Improvement

Decreasing percentage of fat. Decrease caloric intake through diet. Increase caloric expenditure through physical

activity and exercise. Moderate decrease in caloric intake and moderate

increase in caloric expenditure.

Follow sound practices. Obsession with weight loss, in conjunction with

many other factors, may contribute to the development of an eating disorder.

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Measurement of Body Composition

Hydrostatic weighing

Skinfold measurements

Body mass index (BMI)

Dual-energy x-ray absorptiometry (DXA)

Bioelectrical impedance

PERCENT BODY FAT NORMS FOR MEN AND WOMEN

Description Women MenEssential Fat Athletes Fitness Acceptable Obesity

10-13%14-20%21-24%25-31%>32%

2-5%6-13%14-17%18-24%>25%

*Source: ACE Lifestyle & Weight Management Consultant Manual

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Muscular Strength & Endurance

Muscular strength is the ability of a muscle or a muscle group to exert a single force against a resistance.

Muscular endurance is the ability of a muscle or muscle group to exert force repeatedly or over a period of time.

Maintenance of proper posture; protect joints.

Production of power to enhance performance.

Use it of lose it!

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Exercises

Isometric Exercises Muscle exerts force against an immovable object. Static contraction.

Isotonic Exercises Force is generated while the muscle is changing

in length. Concentric and eccentric contractions.

Isokinetic Exercises Contractions are performed at a constant velocity

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Development of Muscular Strength and Endurance

Principle of Overload is critical.

Repetition - performance of a movement through the full range of motion.

Set - number of repetitions performed without rest.

Strength Low number of repetitions with a heavy resistance.

Endurance High number of repetitions with a low resistance

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Muscular Strength and Endurance

FITT Formula

Frequency: 3 days per week

Intensity: Strength: 6-8 repetitions.Endurance: 12-20 repetitions.

Time: 1 – 3 sets

Type: Isotonic or progressive resistance exercises; can also use isometric and isotonic exercises.

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Flexibility

Maximum range of motion possible at a joint.

Joint specific: better range of motion in some joints than in others.

Can prevent muscle injuries & low-back pain.

Decreased flexibility can be caused by: Sedentary lifestyle (lack of use of muscles) Age High amounts of body fat Stress

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Improvement of Flexibility

Ballistic Stretching Momentum generated from repeated bouncing to

stretch. (Not recommended)

Static Stretching Slowly moving into a stretching position and holding

for a certain period of time (10-30 seconds; 5 times).

Contract-relax Technique Relaxing of the muscle to be stretched by contracting

the opposite muscle (hamstrings/quadriceps)

Measurement of Flexibility - goniometer

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Flexibility

FITT FormulaFrequency: 2 to 3 days per week

(recommended every day)

Intensity: Stretch past the normal length until resistance is felt

Time: Hold the stretch from 5 – 10 seconds initially, building to 30 – 45 seconds

Type: Static or contract-relax techniques

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Developing a Fitness Program

Medical conditions, such as heart disease, diabetes, and asthma must be taken into account.

Consider the participant’s fitness needs and goals.

Activities selected should allow participants to achieve the desired fitness goals while maintaining interested and enjoyment.

Attention must be directed to educating participants about the principles of designing a personal exercise program, assessing their own fitness, and resolving personal fitness problems.

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Effects of Training

Lower oxygen consumption

Lower pulse rate

Larger stroke volume

Lower rise in blood pressure

Slower respiration rate

Lower rate of lactic acid formation

Faster return to “normal”

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Environmental Considerations

Hot and humid weather Use extreme caution Heat cramps, heat

exhaustion, heat stroke Fluid replacement Adaptation

Extreme cold weather Heat conservation Hypothermia Frostbite

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Nutrition and Fitness

Nutrients carbohydrates fats proteins vitamins minerals water

Maintaining water balance is important.

A well-balanced diet is necessary to obtain all the nutrients required by the body.

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Nutrition

Food pyramid offers guidelines for eating a balanced diet.

Current U.S. diet is too high in fat, cholesterol, sugar, and sodium while lacking in carbohydrates and fiber.

Carefully monitor caloric intake AND caloric expenditure.

Special diets for special situations.

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US Dietary Guidelines - 2005

Consume adequate nutrients within caloric needs.

Maintain body weight within a healthy range.

Engage in regular physical activity (PA). 30 minutes of moderate-intensity PA/day to reduce

risk of chronic disease Greater health benefits can be accrued from

engaging in PA for a longer time and/or at a greater level of intensity

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US Dietary Guidelines - 2005

Consume a sufficient amount and variety of fruits and vegetables.

Consume at least half of your grains from whole grains.

Consume 3 cups/day of fat-free or low-fat milk or equivalent mild products.

Limit consumption of saturated fatty acids, trans fatty acids, and sodium.

Consume potassium-rich foods.

Drink alcoholic beverages in moderation.

Safely prepare foods to avoid illness.

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Ergogenic Aids

Work-producing substances or phenomena believed to increase performance.

Used to enhance energy use, production, and/or recovery in quest for improved performance.

Forms of Ergogenic Aids: Mechanical Psychological Pharmacological Physiological Nutritional

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Caffeine

Stimulant, restricted by IOC – standard up to 6 to 8 cups of coffee.

Enhances muscle tension development, increased alertness, decreased perception of fatigue, increased endurance performance.

Effect depends on dosage and amount of caffeine athlete typically consumes.

Side effects – very rapid heart rate, diuresis, insomnia, nervousness, diarrhea, anxiety.

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Carbohydrate Loading

Used in endurance events lasting 60 to 90 minutes or longer in order to maintain pace and delay fatigue.

Change training regimen and modify diet to eat more complex carbohydrates than normal in order to store additional glycogen in muscles and liver to provide extra energy.

Pre-event meal – 1 to 5 grams of carbohydrate per kilogram of body weight 1 to 4 hours prior to event.

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Hydration, Energy & Sports Drinks

Proper hydration is important for safety reasons and to improve performance.

Fluid replacement during exercise is associated with lower heart rate, body core temperature, and levels of perceived exertion.

Water – 4-6 ounces for every 15-20 minutes of exercise.

Sports and/or energy drinks – add fluid as well as replace lost electrolytes and supply additional carbohydrates.

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Creatine

Used in an effort to increase stores of muscle phosphocreatine and have more fuel available to support short, high intensity activity.

Used in conjunction with a resistance training program to maximize muscle strength and increase fat-free mass.

ACSM – creatine supplementation enhances exercise performance in events involving short periods of extremely powerful activity, especially during repeated efforts.

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Anabolic-Androgenic Steroids

Synthetic forms of male hormone testosterone – testosterone secreted by testes is responsible for the development of masculine characteristics and promotion of growth of tissue, muscle mass, weight, and bone growth.

Taken orally or injected in 10 to 100 times the recommended therapeutic dosage.

Banned by IOC and some sport organizations.

Serious side effects, some irreversible, associated with chronic use including: increased risk of heart disease, liver tumors, cancer, hypertension, mood swings, aggressive behavior.