The Child and Sport Performance

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The Child and Sport Performance

• Is competition physically harmful for the
  preadolescent?

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The Child and Sport Performance

• Should preadolescents be allowed to compete in
  physically demanding activities (e.g. long
  distance running or strength training)?

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The Child and Sport Performance

• Physical capabilities of the young exerciser.

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The Child and Sport Performance

• Differences between young and adult exercisers.

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The Child and Sport Performance

• The impact of such differences on training and
  performance.

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The Child and Sport Performance

• Maturational Differences
• The peak rate of growth in height occurs at age
  12 in girls and 14 in boys.
• Full height is typically attained by age 16-17 in
  girls and age 18 in boys.

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The Child and Sport Performance

• The peak rate of weight increase occurs at age 12
  in girls and at age 14-15 in boys.
• Muscle mass increases steadily along with weight
  gain from birth through adolescence.

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The Child and Sport Performance

• In males, the rate of muscle mass increase peaks
  at puberty, when testosterone production
  increases dramatically.
• Girls do not experience this sharp increase in
  muscle mass.

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The Child and Sport Performance

• Muscle-mass increases in boys and girls result
  primarily from fiber hypertrophy (increase in
  cell size) with little or no hyperplasia
  (increase in cell number).

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The Child and Sport Performance

• Muscle mass peaks in girls between ages 16 and
  20, and in boys between ages 18 and 25, though it
  can be increased more through diet and exercise.

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The Child and Sport Performance

• Fat cells can increase in size and number
  throughout life.
• The amount of fat accumulation depends on diet,
  exercise habits, and heredity.

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The Child and Sport Performance

• At physical maturity, the bodys fat content
  averages 15 in males and 24 in females.
• The differences are caused primarily by higher
  testosterone levels in males and higher estrogen
  levels in females.

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The Child and Sport Performance

• Bones are formed through ossification, which
  spreads from primary (diaphysis) and secondary
  (epiphysis) ossification centers.
• Injury at the epiphysis could cause early
  termination of growth.

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The Child and Sport Performance

• Competitive baseball, especially the pitching
  motion, carries the highest risk of epiphyseal
  injury.
• Tennis and swimming also carry higher risks for
  young athletes.

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The Child and Sport Performance

• All lung volumes increase until physical
  maturity.
• There is a direct relationship between body size
  and ventilatory capacities during exhaustive
  exercise.

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The Child and Sport Performance

• Blood pressure is also directly related to body
  size.
• It is lower in children than adults but increases
  to adult levels in the late teen years.

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The Child and Sport Performance

• During both submaximal and maximal exercise, the
  childs smaller heart and blood volume result in
  a lower stroke volume than in adults.
• In partial compensation, the childs heart rate
  is higher than an adults.

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The Child and Sport Performance

• Even with increased heart rate, a childs cardiac
  output remains less than an adults.
• In submaximal exercise, an increase in the a-vO2
  difference ensures adequate oxygen delivery to
  the active muscles.

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The Child and Sport Performance

• But at maximal work rates, oxygen delivery limits
  performance.

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The Child and Sport Performance

• As pulmonary and cardiovascular function improve
  with continued development, so does aerobic
  capacity.
• VO2 max, expressed in L. min-1, peaks between
  ages 17 and 21 years in males and between 12 and
  15 years in females, after which it steadily
  decreases.

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The Child and Sport Performance

• When VO2 max is expressed relative to body
  weight, it plateaus in males from age 6 to 25
  years, but begins its decline at about age 13 in
  girls.
• However, expressing VO2 max relative to body
  weight might not provide an accurate estimate of
  aerobic capacity.

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The Child and Sport Performance

• Such VO2 max values do not reflect the
  significant gains that are noted with both
  maturation and training.

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The Child and Sport Performance

• The childs lower VO2 max value in (L. min-1)
  limits endurance performance.

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The Child and Sport Performance

• When expressed relative to body weight, a childs
  VO2 max is similar to an adults, yet in
  activities such as distance running a childs
  performance is far inferior to adult performance
  because of difference in economy of effort.

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The Child and Sport Performance

• The childs ability to perform anaerobic activity
  is limited.
• A child has a lower glycolytic capacity, possibly
  because of a limited amount of phosphofructokinase
  .

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The Child and Sport Performance

• Children cannot attain high respiratory exchange
  ratios during maximal or exhaustive exercise,
  suggesting less lactate production.
• Anaerobic mean and peak power outputs are lower
  in children than in adults.

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The Child and Sport Performance

• Laboratory studies indicate that children are
  more susceptible to injury or illness from
  thermal stress.
• Children are capable of less evaporative heat
  loss than adults because children sweat less
  (less sweat is produced by each active sweat
  gland).

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The Child and Sport Performance

• Youngsters acclimatize more slowly than adults do.

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The Child and Sport Performance

• Children appear to have greater conductive heat
  loss than adults, which should place children at
  greater risk for hypothermia in cold environments.

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The Child and Sport Performance

• Until more is known about childrens
  susceptibility to thermal stress, a conservative
  approach should be used for children who exercise
  in temperature extremes.

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Summary

• Aerobic training in preadolescents does not alter
  VO2 max as much as would be expected for the
  training stimulus, possibly because VO2 max is
  dependent on heart size.
• But, endurance performance does improve with
  training.

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Summary

• A childs anaerobic capacity is increased with
  anaerobic training.

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Summary

• Regular training typically results in
• decreased total body fat
• increased fat-free mass
• and increased total body mass.

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Summary

• In general, growth and maturation rates and
  processes are probably not altered significantly
  by training.

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The Child and Sport Performance

• See Strength Training Recommendations for
  Prepubescent Children.

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The Child and Sport Performance

• See Basic Guidelines for Resistance Exercise
  Progression in Children

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Summary

• Animal studies suggest that resistance training
  can lead to stronger, broader, more compact bone.
• The risk of injury from resistance training in
  young athletes is relatively low and the programs
  they should follow are very much like those of
  adults.

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Summary

• Strength gains achieved from resistance training
  in preadolescents result primarily from
• improved motor skill coordination
• increased motor unit activation,
• and other neurological adaptations.

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Summary

• Unlike adults, preadolescents who resistance
  train experience little change in muscle size.