Download Age and Sex considerations in Sport and Exercise

Age and Sex Considerations in
Sport and Exercise
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Phases of Growth and Development
Infancy:
first year of life
Childhood:
age 1 to puberty
Puberty:
development of secondary sex characteristics; sexual
reproduction becomes possible
Adolescence:
puberty to completion of growth and development
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Changes With Age in the Rate
of Increase in Height (cm/yr)
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Height and Weight
• The rate of growth is slower throughout childhood until a marked increase
occurs near puberty
• Full height is typically achieved at age 16 in girls and 18 in boys
• Growth in weight follows the same trend as height, with the peak rate of
weight increase occurring at age 12.5 in girls and 14.5 in boys
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Muscle Growth
• Muscle development rate peaks at puberty in boys corresponding with a
~10-fold increase in testosterone
• In girls, skeletal muscle mass increases from 25% of body weight at birth
• Muscle development is slower in girls
• Muscle development primarily results from hypertrophy of existing fibers
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Growth and Fat Storage
• Fat cells form and fat deposition starts in fetal development
• Fat is stored by increasing the size and number of fat cells
• Fat storage depends on
• At birth, 10-12% of total body weight is fat
• At maturity, fat content averages 15% of total body weight in males and
25% in females
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Changes in Percent Fat, Fat Mass, and Fat-Free Mass for
Females and Males From Birth to 20 Years of Age
Reprinted, by
permission, from
R.M. Malina, C.
Bouchard, and O.
Bar-Or, 2004,
Growth, maturation,
and physical
activity, 2nd ed.
(Champaign, IL:
Human Kinetics),
114.
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Strength
• Improves as muscle mass increases
• Peak strength occurs at
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Cardiovascular and Respiratory Function
Children have smaller hearts and blood volume
Maximal Exercise
• Maximal heart rate is higher in children than adults (MHR = 220 – age)
• Lower maximal cardiac output in children
• Oxygen delivery limits performance in children
Lung. Function
• Lung volumes increase until physical maturity, primarily because of
increasing body size
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Physiological Adaptations to Training
Body composition changes with training in children and adolescents are
similar to those seen in adults
With both resistance and aerobic training, boys and girls will:
Endurance performance improves with aerobic training in preadolescents
.
A child’s anaerobic capacity increases with anaerobic training
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Sport Performance
• Records in running, swimming, cycling, and weightlifting indicate that we
are in our physical and physiological prime in our 20s and early 30s
• Most athletic performances decline steadily because of decrements in
endurance and strength
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Change With Age in Men’s and Women’s World
Records for (a) 100 m
and (b) 10 km Runs
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Introduction: Sex Differences
in Athletic Performance
Things to consider:
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Body Size and Composition
Until puberty, girls and boys do not differ significantly in most
measurements of body size and composition
• Puberty in girls: follicle stimulating hormone (FSH) and luteinizing
hormone (LH) cause estrogen production from the ovaries
– Causes pelvis broadening
– Breast development
– Increased bone growth
• Puberty in boys: FSH and LH cause testosterone production from
the testes
– Stimulates EPO production from the kidneys
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Changes in Blood Concentrations of Testosterone and
Estrogen From Birth to Adulthood
Reprinted, by permission, from R.M. Malina, C. Bouchard, and O. Bar-Or, 2004, Growth,
maturation, and physical activity, 2nd ed. (Champaign, IL: Human Kinetics), 414.
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.
Range of VO2max for Female and Male Nonathletes and
for Female and Male Elite Athletes
Data from L. Hermansen and K.L. Andersen, 1965, "Aerobic work capacity in young
Norwegian men and women," Journal of Applied Physiology 20: 425-431.
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Training and Body Composition
in Women
• With either cardiorespiratory endurance training or resistance training, both
men and women:
• Magnitude of changes in body composition are more related to energy
expenditure than participant’s sex
• Density of bones increases with weight-bearing exercise
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Strength Training
• Women have less muscle mass
• Similar to men, women gain considerable strength through strength training
• Strength gains are usually not accompanied by a large increase in muscle
bulk
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Sport Performance
Sex differences are more pronounced in events where high levels of upper
body strength are required (e.g., shot put)
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Women’s and Men’s World Records in Six Running Events Between 1960 and
2006
(continued)
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Eating Disorders
• Eating disorders: a group of disorders that must meet specific criteria
established by the American Psychiatric Association
– Anorexia nervosa
– Bulimia nervosa
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Anorexia Nervosa
• Distorted body image
• Intense fear of fatness or gaining weight
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Bulimia Nervosa
• A feeling of lack of control during binges
• Purging behavior, which can include self-induced vomiting, laxative use,
and/or diuretic use
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3 Categories of High-Risk Sports
for Disordered Eating
1.
2.
3.
Appearance sports: diving, figure skating, gymnastics, bodybuilding, and
ballet
Endurance sports: distance running and swimming
Weight-classification sports: horse racing (jockeys), boxing, and
wrestling
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Exercise Physiology in
schools
How is all of this stuff relevant??
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The Obesity Crisis
• Discourage forms of comparison between kids
• Encourage personal comparisons
• Psychological/ motivational factors
• Increase chances of success in all students
– Pedometers
– Strength
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Develop muscle strength
• Number of muscle fibres is fixed at birth
• Increases in strength more likely than size
• Active muscles = greater increase
• Doesn’t mean lifting weights!
• Means weight bearing exercise- running, aerobics
• And resistance exercise using body weight- push ups, sit ups, jumping etc
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Heart rate
•Decrease in RHR with increased
fitness same as in adults
•This activity allows kids to track the
change in their hear rate, and you can
explain what is happening as this
occurs
•Left ventricle increases ability to
pump blood around to the
muscles
•Therefore it doesn’t have to
pump as often to get the blood to
go around
•So a decrease in RHR is a direct
representation of your heart
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getting stronger!
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Fitness Testing?
•
•
•
•
Focus on individual comparison and improvement
Gain a holistic understanding of fitness
Experience feeling of improving fitness
Needs to be done correctly
– Self Esteem
– Ensure privacy- secret!
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ACHPER
• Growth: Height and Weight, with Body
Mass Index (BMI) calculated by the
computer program.
• Cardiorespiratory Endurance: MultiStage Fitness Test and 1.6 km run/walk.
• Muscular Strength and Endurance: The
Curl-up and the Basketball Throw.
• Muscle and Joint Flexibility: The Sit and
Reach Tests and Shoulder Stretch.
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Programs
• Kids should be active for an hour a day
• Map out all school and after school activities
to see if you are getting enough
• Suggest FUN stuff that counts as activity!
• Incentive programs
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