HB100 Level 1 Physiology

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HB100 - Level 1 Physiology
Growth, Development and Exercise
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Terminology
Growthan increase in the size of the body or its
parts
Developmentthe functional changes that occur
with growth
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Phases of Growth and Development
Infancyfirst year of life
Childhoodage 1 to puberty
Pubertydevelopment of secondary sex
characteristics and capability of sexual
reproduction
Adolescencepuberty to completion of growth and
development
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RATE OF INCREASE IN HEIGHT AND WEIGHT
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BONE OSSIFICATION
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Bone Growth
w Is complete when cartilage cells stop growing
and epiphyseal plates are replaced by bone (by
early 20s)
w Requires rich blood supply to deliver essential
nutrients
w Requires calcium to help build and maintain
strength
w Slows or breaks down when blood calcium levels
are too low
w Is helped by exercise which affects bone width,
density, and strength
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Bone Injuries and Growth
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Muscle Growth
w Results primarily from hypertrophy of existing
fibers
w Muscle length increases with bone growth due to
increase in sarcomeres
w Boys muscle mass peaks at 50 of body weight
at 18 to 25 years
w Girls muscle mass peaks at 40 of body weight
at 16 to 20 years
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Growth and Fat Storage
w Fat is stored starting at birth
w Fat is stored by increasing the size and number
of fat cells
w Fat storage depends on diet, exercise habits,
and heredity
w At maturity, fat content averages 15 in males
and 25 in females
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SKINFOLD FAT IN CHILDREN
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CHANGES IN FAT AND FAT-FREE MASS
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Key Points
Tissue Growth and Development
w Girls mature physiologically about 2 to 2.5
years earlier than boys do.
w Bones are formed through an ossification
process which is usually complete by ones early
20s.
w Injury of a bones epiphysis could cause delays
in its growth.
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Key Points
Tissue Growth and Development
w Fat storage occurs due to increases in the size
and number of fat cells.
w Fat storage starts at birth and is influenced
throughout life by diet, exercise, and heredity.
w Balance, agility, and coordination improve as
childrens nervous systems develop.
w Myelination of nerve fiberswhich speeds the
transmission of impulsesis necessary before fast
reactions and skills are fully developed.
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Physical Performance and Maturation
w Motor ability increases
w Strength increases
w Lung volume and peak flow increase
w Blood pressure, heart size, and blood volume
increase
w Heart rate decreases
w Aerobic and anaerobic capacities and running
economy increase
w Heat and cold tolerance increases
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STRENGTH GAINS WITH AGE
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STRENGTH CHANGES WITH DEVELOPMENT
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Key Points
Pulmonary Function and Growth
w As body size increases, lung size and lung
function increase.
w Lung volumes and peak flow increase until
growth is complete.
w Boys' absolute lung volumes and peak flow
values are higher than girls' absolute values due
to girls smaller body size.
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Submaximal Exercise and Growth
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SUBMAXIMAL HEART RATE AND STROKE VOLUME
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Key Points
Maximal Exercise and Growth
w HRmax is higher in children but decreases
linearly with age.
w Lower oxygen delivery capacity limits
performance at high absolute rates of work.
w At relative rates of work (moving own body
weight) oxygen delivery capacity does not limit
performance.
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Key Points
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Anaerobic Capacity in Children
w Ability to perform anaerobic activities is lower
w Glycolytic capacity is lower
w Produce less lactate and cannot attain high RER
values during maximal exercise
w Anaerobic mean and peak power outputs are lower
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AEROBIC AND ANAEROBIC DEVELOPMENT
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Thermal Stress and Children
w Evaporative heat loss is lower due to less
sweat being produced by sweat glands.
w Acclimatization to heat is slower in boys than
adult men.
w Conductive heat loss is greater, increasing
risk for hypothermia.
w Exercising in extreme temperatures should be
minimized.
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Resistance Training in Preadolescents
w May protect against injury and help build bones
w Improves motor skill coordination
w Increases motor unit activation
w Results in other neurological adaptations
w Causes little change in muscle size
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A THEORETICAL MODEL FOR STRENGTH ADAPTATIONS
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Key Points
Training the Young Athlete
w Training programs for children should be
conservative to reduce the risk of injury,
overtraining, and loss of interest in the sport.
w An appropriate resistance training program is
relatively safe for children.
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Key Points
Training the Young Athlete
w Anaerobic capacity increases with aerobic
training.
w Regular training typically results in decreased
total body fat, increased fat-free mass, and
increased total body mass.
w Generally, training does not appear to
significantly alter growth and maturation rates.