Transcript Exercise Physiology and Fitness - McGraw

Exercise Physiology & Fitness
Chapter 7
©2009 McGraw-Hill Higher Education. All rights reserved.
Exercise Physiology & Fitness
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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?
©2009 McGraw-Hill Higher Education. All rights reserved.
Exercise Physiology
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The study of the effects of exercise on the
body.
Body’s responses and adaptations to
exercises
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System to subcellular level
Acute (short term) to chronic (long term) adaptations
Population served
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Elite performer
People of all ages and abilities
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Historical Development
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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
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1970s: APS recognized exercise physiology as a
specialized area of physiology.
1974: ACSM: Guidelines for Graded Exercise Testing and
Prescription
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1980s and 1990s: Increased understanding of the
relationship between physical activity and health.
 1996:Surgeon General’s Report Physical Activity &
Health
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2000: 1st certification exams for Clinical Exercise
Physiologists
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Areas of Study
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Effects of various
exercises on various
systems of the body
Relationship of energy
metabolism to
performance
Effectiveness of training
programs
Effects of environmental
factors on performance
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Identification of factors
that limit performance
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
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Cardiac rehabilitation
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Assessment of cardiovascular functioning
Prevention of cardiovascular disease
Rehabilitation of individuals with the disease
Exercise biochemistry
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Effects of exercise at the cellular level
Exercise epidemiology: Relationship between
physical activity and mortality
Pediatric exercise science:Scientific study of the
response of the body to exercise during childhood and
maturation.
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Physical Fitness
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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.”
©2009 McGraw-Hill Higher Education. All rights reserved.
Physical Fitness
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Health fitness
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Body composition
Cardiorespiratory
endurance
Flexibility
Muscular endurance
Muscular strength
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Performance fitness
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Agility
Balance
Coordination
Endurance
Flexibility
Muscular endurance
Muscular strength
©2009 McGraw-Hill Higher Education. All rights reserved.
Physical Activity and Health
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Chronic disease – major threat to health
today
Hypokinetic diseases
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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
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Inactivity a risk factor for several
diseases
Individuals who lead a sedentary
lifestyle have increased risk of
morbidity and mortality.
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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
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What kind of activity?
How much time spent in activity?
At what intensity should it be
performed?
How often in order to see benefits?
©2009 McGraw-Hill Higher Education. All rights reserved.
Consensus Statement
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There is an inverse and generally linear
relationship for rates of all-cause mortality, total
CVD, and CHD incidence and mortality and for
the incidence of type 2 diabetes.
Accumulation of at least 30 minutes of
moderate-intensity PA on most days of the week
is associated with a significant 20%-30%
reduction in all-cause mortality.
Additional benefits can be derived from
increasing the amount and/or intensity of physial
activity.
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Health Benefits
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Enhanced cardiovascular function
Reduction of many cardiovascular disease risk
factors
Increase 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
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Management of stress
Enhancement of self-concept and esteem
Socialization through participation in physical
activities
Improved overall general motor performance
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
©2009 McGraw-Hill Higher Education. All rights reserved.
Energy Production for PA
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Use of ATP as energy to perform muscular
activity. Two ways to produce ATP:
Anaerobic system
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Without oxygen
High energy expenditure, short time (6-60 seconds)
Aerobic system
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With oxygen
Lower rate of energy expenditure, longer period of
time (more than 3 minutes)
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Principles of Fitness Training
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Principle of overload
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Principle of specificity
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Design program to reflect specific goals.
Principle of progression
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To improve improvements in health and fitness, an
increased workload must be placed on the body.
Overload should be applied gradually, and steadily
increased as the body adapts.
Principle of diminishing returns
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As fitness increases, gains achieved become less and
less as individuals approach limits of adaptability
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Principles of Fitness Training
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Principle of variation
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Variation helps maintain individuals’ interest and
provides a change of pace while continuing to make
progress toward desired goals
Principle of reversibility
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“Use it or lose it” – inactivity leads to gradual erosion
of benefits achieved
Cardiovascular gains can disappear within 510 weeks of inactivity
Some strength gains persist for 6 months to 1
year after cessation of training
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Principles of Fitness Training
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Principle of individuality
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Principle of recovery
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Individuals respond differently to exercise and
will vary in their rate of improvement and
levels of achievement.
Rest allows the body to recover and adapt to
the changes placed on it
Principles of safety
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Safety is paramount
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Principles of Fitness Training
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Include warm-up and cool down as
part of the training program
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Helps prevent injury and prepares body for
exercise as well as returns it to a normal
state.
Consider behavioral factors
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Motivation of individual to adhere to fitness
program
Promote adherence through strategies as
goal-setting and enhancing self-efficacy
©2009 McGraw-Hill Higher Education. All rights reserved.
Planning a Fitness Program
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Threshold of training
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Target zone
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Defines the upper limits of training and the optimal
level of exercise.
Needs and goals of individual
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Minimal level of exercise needed to achieve desired
benefits.
Program should meet the goals of the individual
FITT Formula
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FITT formula
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Frequency
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Intensity
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Degree of effort put forth during exercise.
Time
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Number of sessions each week
Duration of activity
Type
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Mode of exercise being performed
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Cardiorespiratory Endurance
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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.
©2009 McGraw-Hill Higher Education. All rights reserved.
Cardiorespiratory Endurance
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Frequency: 3 to 5 times per week
Intensity:
55% - 90% HRMAX
40% - 85% HRR
Time:
20 - 60 minutes
Type:
Aerobic activities
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Target Zone
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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
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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.
©2009 McGraw-Hill Higher Education. All rights reserved.
Body Composition
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Body composition is influenced by nutrition
and physical activity.
Energy balance is important to achieving a
favorable body composition.
Energy expenditure through:
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basal metabolism (maintenance of essential life
functions)
work (including exercise)
excretion of body wastes
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Classifications for BMI
Body Mass Index
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Estimated –
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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
Classification
BMI
Underweight
<18.5 kg/m2
Normal weight
18.5 - 24.9 kg/m2
Overweight
25 - 29.9 kg/m2
Obesity (Class 1)
30 - 34.9 kg/m2
Obesity (Class 2)
35 - 39.9 kg/m2
Extreme Obesity (Class 3)
 40 kg/m2
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Energy Balance
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Number of calories taken into the body as food
minus number of calories expended
Caloric expenditure
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Neutral balance
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Positive balance
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Caloric intake equals expenditure.
More calories consumed than expended.
Negative balance
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More calories are expended than consumed.
©2009 McGraw-Hill Higher Education. All rights reserved.
Body Composition Improvement
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Decreasing percentage of fat
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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
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Obsession with weight loss, in conjunction with many
other factors, may contribute to the development of an
eating disorder.
©2009 McGraw-Hill Higher Education. All rights reserved.
Measurement of Body
Composition
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Hydrostatic weighing
Skinfold measurements
Body mass index (BMI)
Dual-energy x-ray absorptiometry (DXA)
Bioelectrical impedance
©2009 McGraw-Hill Higher Education. All rights reserved.
Muscular Strength & Endurance
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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!
©2009 McGraw-Hill Higher Education. All rights reserved.
Exercises
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Isometric exercises
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Isotonic exercises
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Muscle exerts force against an immovable object.
Static contraction
Force is generated while the muscle is changing in
length.
Concentric and Eccentric contractions
Isokinetic exercises
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Contractions are performed at a constant velocity
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Development of Muscular
Strength and Endurance
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Principle of Overload is critical.
Repetition - performance of a movement
through the full range of motion.
Set - number of repetitions performed without
rest.
Strength
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Low number of repetitions with a heavy resistance.
Endurance
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High number of repetitions with a low resistance
©2009 McGraw-Hill Higher Education. All rights reserved.
Flexibility
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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:
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Sedentary lifestyle (lack of use of muscles)
Age
High amounts of body fat
Stress
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Improvement of Flexibility
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Ballistic stretching
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Static stretching
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Slowly moving into a stretching position and holding for
a certain period of time (10-30 seconds; 5 times).
Contract-relax technique
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Momentum generated from repeated bouncing to
stretch. (Not recommended)
Relaxing of the muscle to be stretched by contracting
the opposite muscle (hamstrings/quadriceps)
Measurement of flexibility - goniometer
©2009 McGraw-Hill Higher Education. All rights reserved.
Conducting Fitness Programs
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Provide for cognitive and affective goals as
well as physical activity.
Make fitness enjoyable.
Establish goals and a plan of action to
attain them.
Monitor progress.
Provide for maintenance of fitness.
Fitness requires personal commitment.
©2009 McGraw-Hill Higher Education. All rights reserved.
Effects of Training
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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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Effects of Training
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Greater cardiorespiratory efficiency.
Greater endurance.
More “work” can be performed at less
cost.
Improvement in fitness components.
Coordination and timing of movements
are better.
©2009 McGraw-Hill Higher Education. All rights reserved.
Physical Activity & Health
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Adults - 30 minutes of physical activity equal to
brisk walking on most, preferably all, days of the
week.
Children – 60 minutes of physical activity on most,
preferably all, days of the week
Activity of greater intensity will yield greater health
benefits.
Strength-developing activities at least twice a
week.
Physical activity as an integral part of one’s
lifestyle.
©2009 McGraw-Hill Higher Education. All rights reserved.
Environmental Considerations
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Hot and humid weather
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Use extreme caution
Heat cramps, heat exhaustion, heat stroke
Fluid replacement
Adaptation
Extreme cold weather
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Heat conservation
Hypothermia
Frostbite
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Nutrition and Fitness
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Nutrients
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carbohydrates
fats
proteins
vitamins
minerals
water
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Maintaining water
balance is
important.
A well-balanced diet
is necessary to
obtain all the
nutrients required
by the body.
©2009 McGraw-Hill Higher Education. All rights reserved.
Nutrition
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Food pyramid offers guidelines for eating a
balanced diet.
Current U.S. diet is too high in fat,
cholesterol, sugar, and sodium and lacking
in carbohydrates and fiber.
Carefully monitor caloric intake AND
caloric expenditure.
Special diets for special situations.
©2009 McGraw-Hill Higher Education. All rights reserved.
US Dietary Guidelines - 2005
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Consume adequate nutrients within caloric
needs
Maintain body weight within a healthy range
Engage in regular physical activity (PA)
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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
©2009 McGraw-Hill Higher Education. All rights reserved.
US Dietary Guidelines - 2005
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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 and trans
fatty acids
Limit consumption of sodium
Consume potassium-rich foods
Drink alcoholic beverages in moderation
Safely prepare foods to avoid illness
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Ergogenic Aids
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Work-producing substances or phenomena
believed to increase performance
Used to enhance energy use, production,
and/or recovery in quest for improved
performance
Forms
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Mechanical
Psychological
Pharmacological
Physiological
Nutritional
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Caffeine
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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 Leading
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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
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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
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Used in an effort to increase stores of muscle
phosophocreatine 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
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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.
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