Chapter 18 Growth, Development, and Exercise in Children and Adolescents

Malina and Bouchard’s definition of growth, development, and maturation Growth  an increase in the size of the body as a whole or the size of particular body parts Development: –Biological—the differentiation of cells along specialized lines of function –Behavioral  development of competence in a variety of areas as the child adjusts to the surrounding culture Maturation  the tempo and timing of progress toward the mature biological state Visit Physical Fitness and Activity in Schools and

Infancy, childhood, and adolescence Infancy –The first year of life –Time of rapid growth in all body functions and physical characteristics Childhood –The time between the first birthday and puberty –Steady growth and maturation –Rapid growth in motor development Adolescence –Defined by the adolescent growth spurt and onset of puberty –Ranges from 8 to 19 years for females and years for males –High degree of variability in maturational status and in strength, sports skills, and performance

The onset of puberty –Important to be able to identify the onset of puberty –Normal growth patterns and responses to exercise training are substantially different in children than in adolescents Visit the American Academy of Pediatrics at

Using height and body weight data to identify the adolescent growth spurt Examine the yearly change in height or body weight as a function of age Dramatic increases in height and body weight coincide with the onset of puberty Increases change from around –5 cm per year to 10 cm per year for height –3 kg per year to 10 kg per year for weight

Peak height velocity occurs at approximately 13 years of age for females and 14 years of age for males

Peak weight velocity occurs at approximately years of age for females and 14 years of age for males

Height and body weight Normal growth in height and body weight develops along an S-shaped curve from birth through adolescence. At adolescent growth spurt, males exhibit a dramatic increase in height and body weight while females begin to level off. Athletic participation has no effect on normal growth and maturation.

(A) Height and (B) body weight develop along an S-shaped curve throughout childhood and adolescence

Body composition Physical activity: –results in lower levels of percent body fat and fat weight and increases fat-free weigh –can improve athletic performance by developing sport-specific body composition –can decrease the health risks associated with obesity

Changes in (A) fat-free weight, (B) fat weight, and (C) percent body fat during childhood and adolescence in males and females

Why VO 2 max increases during childhood result from growth in Lungs Circulatory system Musculature

Normal developmental patterns of absolute VO 2 max Males: –childhood: increases throughout –adolescence: continues to increase Females: –childhood: increases throughout –adolescence: levels off at about age 14

Absolute maximal oxygen consumption increases in males but plateaus at approximately 14 years of age in females

Relative (to body weight) maximal oxygen consumption (VO 2 max) remains stable during childhood and adolescence in males but decreases across age in females

Making weight Excessive weight loss associated with such sports as wrestling, boxing, and gymnastics Often involves drastic changes in caloric intake and water metabolism Can cause changes in kidney and cardiovascular function.

Aerobic fitness and endurance performance in children Relative VO 2 max remains stable or declines during childhood and adolescence. Endurance performance steadily improves. Factors other than VO 2 max must influence endurance performance in children.

Hazards associated with long-distance running and children –Heel cord injuries –Epiphyseal growth plate injuries –Chronic joint trauma –Thermal intolerance –Psychological problems from unrealistic goals

Anaerobic fitness in children and adolescents Children have a lower capacity for anaerobic exercise than adolescents or adults Anaerobic metabolic systems less effective at energy production Poorer performance in high-intensity, short-duration activities Respond well to anaerobic training

Factors to consider when planning an anaerobic training program for children Training program should closely mimic the intended sporting activity with respect to the mode of exercise as well as the metabolic demands. Training protocol should include repetitions that tax the appropriate anaerobic system, whether phosphagens or gylcolysis. For Articles About Anaerobic Training in Children, visit www-unix.oit.umass/~excs597k/labonte/articles.htm

Absolute mean power from the Wingate Anaerobic Test increases across age in males and females

Absolute peak power from the Wingate Anaerobic Test increases across age in males and females

Strength training for children and adolescents Both genders increase in strength across age. At 13 to 14 years of age, males begin to increase at greater rate than females. Strength training is beneficial to both children and adolescents. Visit Strength Training for Children at

Benefits of strength training for prepubescent children –Improved flexibility –Favorable changes in blood lipid profiles –Enhanced bone and connective tissue development –Favorable changes in body composition –Reduced musculoskeletal injuries during sports –Improved motor skills –Increased muscular endurance –Positive psychological effects

Strength increases in response to resistance training in prepubescent children result from Primarily neural adaptations Possibly hypertrophy

Hazards associated with strength training for children and adolescents Acute musculoskeletal injuries such as ruptured disks and damage to the epiphyseal growth plate Chronic musculoskeletal injuries such as stress fractures and strains

Summary of the American Academy of Pediatrics’ recommendations for resistance training for children and adolescents The program should be conducted by well- trained adults who are qualified to plan programs appropriate to the age of the participant. Weight lifting, power lifting, body building, and the use of maximal amounts of weight in strength training should be avoided until the participant has reached Tanner Stage 5 maturity.

Weight training progression for children