Title: Introduction to Nutrition for Health, Fitness, and Sports Performance
1Introduction to Nutrition for Health, Fitness,
and Sports Performance
Williams, 8th edition, Chapter 1
2Starting Points
- Review effects of regular exercise on risk for
disease (Table 1.1) - Review health problems associated with poor
dietary habits (Figure 1.5) - Define moderate amounts of physical activity
(Table 1.2) - What is Sedentary Death Syndrome?Surgeon
Generals Report on Physical Activity and
Fitness weekly caloric expenditure from exercise
should meet or exceed 1000 per week.
3General guidelines for exercise (See pyramid -
Figure 1.3)
- Level I 30 minutes daily low-intensity
- Level II 3-6 days/week, gt 20 minutes at 50-85
increase in heart rate - Level III 3-7 days/week stretching to? fitness
- Level IV 2-3 days/week resistance activities
- Level V physical inactivity (e.g. TV watching
4Can too much exercise be harmful?
- A few health risks of over exercising ?
impaired immune function, increased risk of
injury, and menstrual irregularities for women - See Revised Dietary Guidelines for
Americanshttp//www.health.gov/dietaryguidelines
/Key recommendations - http//www.health.gov/dietaryguidelines/dga2005/re
commendations.htm
5What is fitness?
- Health related fitness
- Body weight and body composition within normal
range - Cardio-respiratory fitness
- Adequate flexibility, strength, and endurance
- Appropriate body composition
- Sports-related fitness ability to maximize
genetic potential with appropriate physical and
mental training
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8- General definition of physical activity is any
movement caused by muscle contraction that
results in caloric expenditure. - Components of Fitness
- Flexibility
- Strength
- Endurance (muscular and cardio-respiratory)
9- Flexibility range of motion of a joint (e.g.
lower back, hamstrings, shoulder rotation) - The structure of the joint itself, and the
muscles and connective tissue (ligaments and
tendons) that surround it restrict flexibility. - Using a variety of stretches will increase
flexibility. Static stretches are most common,
and involve putting the intended muscle to be
stretched into a lengthened position and holding
that stretch for at least 12 - 15 seconds
10Muscular strength and endurance
- Strength ability of muscles to move against
force - Static or isometric strength muscle action
with no noticeable change in muscle length (e.g.
pushing against resistance) - Dynamic constant external resistance (DCER)
training resistance training where external
resistance of weight does no change joint
flexion or extension occurs with each repetition
(formerly known as isotonic exercise) - Dynamic strength measures are done using the one
repetition maximum (1-RM) technique device used
is a dynamometer.
11- Isometric force, no joint movement
- Concentric force, while muscle is shortening
- Eccentric force, while muscle is
lengthening For strength training, apply - Resistance
- Repetition
- Overload
- Result ? hypertrophy
12Isometric exercise
Source www.BodyliciousWorkout.com
13Concentric exercise (biceps curl)
Source www.netfit.co.uk/ assets/bicep8m.gif
14Eccentric exercise
Overhead squat Source http//www.hhs.csus.edu/ho
mepages/khs/Kilogram4/public/KINS20144/Kins144_OS
Q.htm
15- Muscular endurance ability of muscle to sustain
repeated contractions - Measured by field tests (e.g. 60-second sit-up
test, or measuring number of sit-ups done without
rest. - Another test YMCA bench-press test involves
performing standardized repetitions at a rate of
30 per second. - Cardio respiratory endurance
- Ability of heart, blood, and lungs to sustain
moderate to high intensity exercise for 20
minutes or more
16- Overall definition of nutrition sum total of
processes involved in intake and utilization of
food substances by living organisms, including
ingestion, digestion, absorption, transport, and
metabolism of nutrients in food - Sports-related fitness
- Strength
- Power
- Speed
- Endurance
- Sport-specific neuromuscular motor skills
17- Ability to succeed in sports is largely related
to - Genetic endowment
- State of training
- Nutritional status
- Example losing excess body fat will enhance
biomechanical efficiency - Consuming carbohydrates during exercise helps
maintain normal blood sugar levels and delays
fatigue - Adequate dietary iron prevents anemia and ensures
maximal oxygen delivery to working muscles
18- Sports nutrition defined as the application of
eating strategies to promote good health and
adaptation to training, to recover quickly after
each exercise session, and to perform optimally
during competition (Louise Burke, in Williams,
p. 14) - Are athletes getting adequate nutrition?
- Groups that may be at risk due to restrictive
dieting dancers, gymnasts, body builders,
distance runners are most susceptible to
inadequate diet
19- Malnutrition unbalanced nutrition (either over
or under needs). - Basic purposes of food
- To provide energy (calories)
- To regulate metabolic processes
- To support growth and development
- Certain diet modifications will influence
performance (e.g. high CHO? endurance) - Diet for training Depending upon length and
intensity of exercise ? may need extra 500-1000
extra calories a day.
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22What does a sports nutritionist do?
- Sports nutrition is a specialty that requires
traditional nutritional science studies (minimum
- BS in Nutrition) - Involves investigation of interactions between
dietary manipulations and physical performance - Assessments and recommendations given based on
specific needs of athletes - Ongoing research and review of professional
publications as well as attendance at annual
professional meetings is necessary - See http//www.scandpg.org/ (Sports,
Cardiovascular, and Wellness Nutritionists
Dietetic practice group)
23Chronic training effect
- E.g. effect of early training for long-distance
running increased hemoglobin and myoglobin
production and cytochromes in muscle cells. - These demand increased iron - often a transient
sports anemia may develop. - Excessive training may lead to chronic fatigue
24Role of dietary supplements
- DSHEA definition a food product that has at
least one of following vitamin, mineral, herb,
or botanical, amino acid, metabolite,
constituent, extract, or combination of any of
these - (Note that most Americans do not suffer from
dietary deficiencies, yet over 40 regularly take
supplements) - NOTE Under DSHEA law (1994), any product sold as
a nutritional product is free from FDA
approval, but this does not mean that all
products are safe. FDA must show in court that
there is an unreasonable risk posed by a
supplement to have it taken off market.
25About supplements
- 1. No scientific body regularly recommends
supplements - 2. Food is more than the sum of its nutrients ?
may be other beneficial substances in food,
making them a better choice. Also, nutrients in
food and other food components may be better
absorbed in combination than in isolation. - 3. Dietary supplements vary WIDELY in quality
some brands may contain zero levels of the
active ingredient
26- Ergogenic aid anything that increases work
performance - Different classifications
- 1. Psychological
- 2. Physiological 3. Pharmacological
- 4. Nutritional
- While most nutritional ergogenic aids are legal,
they may not all be safe. - Note dangers of ephedra, DHEA, androstenedione
27- Research and recommendations
- 1. Epidemiological studying large populations
to find relationships between 2 or more
variables researchers trace history and
patterns. (example higher fat diets greater
incidence of heart disease) - 2. Experimental usually double-blind, placebo
controlled lab-based setting, variables are
manipulated. - 3. If study is done to determine effects of a
supplement, good to have many variables tested.
28- Example a study on the effects of a CHO drink
and endurance exercise may involve 2 groups an
experimental group that would receive the
high-CHO drink, and a control group that would
receive a placebo drink. After administering the
drink to both groups, they would perform an
endurance activity (e.g. long distance run or
cycle). Observations might include blood sugar
levels at various time increments of the
exercise, lactate threshold, rating of perceived
exertion, and the length of time each participant
was able to exercise.
29- The independent variable (IV) or the variable
that could be manipulated would be the sports
drink(high CHO or placebo) - The dependent variables (DV) would be blood sugar
levels, lactate threshold, rating of perceived
exertion, and the length of time of exercise. - Another example A study is conducted to examine
the effects of pre-exercise fluidelectrolyte
solution intake on rating of perceived exertion
(RPE) - What is the IV? The DV?
30Epidemiological research
- Studying large populations to find relationships
between 2 or more variables - People (subjects) may be followed for many
years - Example Scientists may be looking at
relationships between diet and exercise practices
and health related indicators (e.g. blood
pressure, Body Mass Index, blood glucose, heart
disease)
31- Characteristics of sound research
- What type of design was used (Experimental?
Double blind?) - Placebo controlled?
- Many variables?
- Were extraneous variables controlled?
- Background or credentials of researchers?
- Who financed the study (is there a conflict of
interest?)
32What is a meta-analysis?
- Review process that involves statistical analysis
of previous studies. - Many studies on a particular subject are reviewed
- Patterns are examined
- (E.g. What are the findings from studies done
over the last 20 years on the effects of caffeine
ingestions on exercise endurance?) - May find meta analyses published in professional
journals
33Next topic
- Review dietary recommendations for athletes
- Must have good working knowledge of exchange
lists and proposed new food guide pyramid - Read Rebuilding the Food Pyramid
- Walter C. Willett and Meir J. Stampfer /
Scientific American Jan03 at http//www.mindfully
.org/Food/2003/Food-PyramidJan03.htm - Be prepared to discuss in next class!!