illinois state university the child and sport performance l is competition physically harmful for...

Illinois State UniversityIllinois State University

The Child and Sport The Child and Sport PerformancePerformance

Is competition physically harmful Is competition physically harmful for the preadolescent?for the preadolescent?



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



Physical capabilities of the young Physical capabilities of the young exerciser.exerciser.



Differences between young and Differences between young and adult exercisers.adult exercisers.



The impact of such differences on The impact of such differences on training and performance.training and performance.



Maturational DifferencesMaturational Differences The peak rate of growth in height The peak rate of growth in height

occurs at age 12 in girls and 14 in occurs at age 12 in girls and 14 in boys.boys.

Full height is typically attained by Full height is typically attained by age 16-17 in girls and age 18 in age 16-17 in girls and age 18 in boys.boys.



The peak rate of weight increase The peak rate of weight increase occurs at age 12 in girls and at age occurs at age 12 in girls and at age 14-15 in boys.14-15 in boys.

Muscle mass increases steadily Muscle mass increases steadily along with weight gain from birth along with weight gain from birth through adolescence.through adolescence.



In males, the rate of muscle mass In males, the rate of muscle mass increase peaks at puberty, when increase peaks at puberty, when testosterone production increases testosterone production increases dramatically. dramatically.

Girls do not experience this sharp Girls do not experience this sharp increase in muscle mass.increase in muscle mass.



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



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



Fat cells can increase in size and Fat cells can increase in size and number throughout life.number throughout life.

The amount of fat accumulation The amount of fat accumulation depends on diet, exercise habits, depends on diet, exercise habits, and heredity.and heredity.



At physical maturity, the body’s fat At physical maturity, the body’s fat content averages 15% in males content averages 15% in males and 24% in females.and 24% in females.

The differences are caused The differences are caused primarily by higher testosterone primarily by higher testosterone levels in males and higher levels in males and higher estrogen levels in females.estrogen levels in females.



Bones are formed through Bones are formed through ossification, which spreads from ossification, which spreads from primary (diaphysis) and secondary primary (diaphysis) and secondary (epiphysis) ossification centers.(epiphysis) ossification centers.

Injury at the epiphysis could cause Injury at the epiphysis could cause early termination of growth.early termination of growth.



Competitive baseball, especially Competitive baseball, especially the pitching motion, carries the the pitching motion, carries the highest risk of epiphyseal injury. highest risk of epiphyseal injury.

Tennis and swimming also carry Tennis and swimming also carry higher risks for young athletes.higher risks for young athletes.



All lung volumes increase until All lung volumes increase until physical maturity.physical maturity.

There is a direct relationship There is a direct relationship between body size and ventilatory between body size and ventilatory capacities during exhaustive capacities during exhaustive exercise.exercise.



Blood pressure is also directly Blood pressure is also directly related to body size.related to body size.

It is lower in children than adults It is lower in children than adults but increases to adult levels in the but increases to adult levels in the late teen years.late teen years.



During both submaximal and During both submaximal and maximal exercise, the child’s maximal exercise, the child’s smaller heart and blood volume smaller heart and blood volume result in a lower stroke volume result in a lower stroke volume than in adults.than in adults.

In partial compensation, the child’s In partial compensation, the child’s heart rate is higher than an adults.heart rate is higher than an adults.



Even with increased heart rate, a Even with increased heart rate, a child’s cardiac output remains less child’s cardiac output remains less than an adult’s.than an adult’s.

In submaximal exercise, an In submaximal exercise, an increase in the a-vOincrease in the a-vO22 difference difference ensures adequate oxygen delivery ensures adequate oxygen delivery to the active muscles.to the active muscles.



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



As pulmonary and cardiovascular As pulmonary and cardiovascular function improve with continued function improve with continued development, so does aerobic capacity.development, so does aerobic capacity.

VOVO22 max, expressed in L max, expressed in L. . minmin-1-1, peaks , peaks between ages 17 and 21 years in males between ages 17 and 21 years in males and between 12 and 15 years in and between 12 and 15 years in females, after which it steadily females, after which it steadily decreases.decreases.



When VOWhen VO22 max is expressed relative max is expressed relative to body weight, it plateaus in males to body weight, it plateaus in males from age 6 to 25 years, but begins its from age 6 to 25 years, but begins its decline at about age 13 in girls.decline at about age 13 in girls.

However, expressing VOHowever, expressing VO22 max relative max relative to body weight might not provide an to body weight might not provide an accurate estimate of aerobic capacity. accurate estimate of aerobic capacity.



Such VOSuch VO22 max values do not reflect max values do not reflect the significant gains that are noted the significant gains that are noted with both maturation and training.with both maturation and training.



The child’s lower VOThe child’s lower VO22 max value in max value in (L(L. . minmin-1-1) limits endurance ) limits endurance performance.performance.



When expressed relative to body When expressed relative to body weight, a child’s VOweight, a child’s VO22 max is similar max is similar to an adult’s, yet in activities such to an adult’s, yet in activities such as distance running a child’s as distance running a child’s performance is far inferior to adult performance is far inferior to adult performance because of difference performance because of difference in economy of effort.in economy of effort.



The child’s ability to perform The child’s ability to perform anaerobic activity is limited.anaerobic activity is limited.

A child has a lower glycolytic A child has a lower glycolytic capacity, possibly because of a capacity, possibly because of a limited amount of limited amount of phosphofructokinase.phosphofructokinase.



Children cannot attain high Children cannot attain high respiratory exchange ratios during respiratory exchange ratios during maximal or exhaustive exercise, maximal or exhaustive exercise, suggesting less lactate production.suggesting less lactate production.

Anaerobic mean and peak power Anaerobic mean and peak power outputs are lower in children than outputs are lower in children than in adults.in adults.



Laboratory studies indicate that Laboratory studies indicate that children are more susceptible to injury children are more susceptible to injury or illness from thermal stress.or illness from thermal stress.

Children are capable of less Children are capable of less evaporative heat loss than adults evaporative heat loss than adults because children sweat less (less because children sweat less (less sweat is produced by each active sweat is produced by each active sweat gland).sweat gland).



Youngsters acclimatize more Youngsters acclimatize more slowly than adults do.slowly than adults do.



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



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


SummarySummary

Aerobic training in preadolescents Aerobic training in preadolescents does not alter VOdoes not alter VO22 max as much as max as much as would be expected for the training would be expected for the training stimulus, possibly because VOstimulus, possibly because VO22 max max is dependent on heart size.is dependent on heart size.

But, endurance performance does But, endurance performance does improve with training.improve with training.


SummarySummary

A child’s anaerobic capacity is A child’s anaerobic capacity is increased with anaerobic training.increased with anaerobic training.


SummarySummary

Regular training typically results Regular training typically results in:in:– decreased total body fatdecreased total body fat– increased fat-free massincreased fat-free mass– and increased total body mass.and increased total body mass.


SummarySummary

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



See Strength Training See Strength Training Recommendations for Recommendations for Prepubescent Children.Prepubescent Children.



See Basic Guidelines for See Basic Guidelines for Resistance Exercise Progression in Resistance Exercise Progression in ChildrenChildren


SummarySummary

Animal studies suggest that resistance Animal studies suggest that resistance training can lead to stronger, broader, training can lead to stronger, broader, more compact bone.more compact bone.

The risk of injury from resistance The risk of injury from resistance training in young athletes is relatively training in young athletes is relatively low and the programs they should low and the programs they should follow are very much like those of follow are very much like those of adults.adults.


SummarySummary

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


SummarySummary

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

illinois state university the child and sport performance l is competition physically harmful for...

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