I. GROWTH AND DEVELOPMENT

Teacher Responsibilities

• Monitor growth and development

• Select objectives based on knowledge of growth and development.

Definitions

• Growth: Change in body size--more cells

• Development: Change in child’s level of functioning

• Maturation: Rate of progress toward a mature state

• Experience: External, environmental variables that may alter the child’s G & D.

Age Periods

• Infancy: Birth to 1 Yr.

• Childhood: 1 Yr to adolescence (11-13)

• Adolescence: Sexual Maturity--onset of secondary sex characteristics– boys: age 10-22, Usually 13-14– girls: age 8-19, Usually 11-12

Body Size

• Standard height and weight

• Hydrostatic skinfold measurements

• Body Size is a better indicator of performance than gender. Boys though, are socialized for activity already at a very young age

Somatotypes

• Endomorph=Round, excessive fat....

• Mesomorph=Prominent and sharp contours, mostly muscle, bone, and connective tissue.

• Ectomorph=lean, thin, little muscle.

• All need to develop motor skills and physical fitness.

Body Proportions

• Girls: relatively wider hips to shoulders during childhood.

• Boys: exactly opposite....mechanical advantage for throwing. This does not mean that girls cannot throw.

• After puberty, boys develop longer legs relative to their trunk compared to girls.

Overall Development

• Optimal periods: Most gain for the least effort

• When rapid development and organization are taking place in the brain and nervous system.

• Trying to speed up maturation is difficult because it is genetically controlled.

Children and Exercise

• Introduction:

• Muscles in action use fuel (glycogen and oxygen) and produce heat.

• Children should drink freely during exercise and activity.

Cardiovascular Response to Exercise

• Heart Rate:– Age 6: 87b/m– Age 13: boys: 66 girls: 70

• Maximum Heart Rate = 220 minus age. • Exercise lowers resting heart rate.• Blood Pressure:

– Increases slightly during childhood and adolescence (110/75)– Girls will be slightly lower than boys– Exercise lowers blood pressure

• Maximal Aerobic Power:– VO2 Max--avg person uses 40-50 ml/kg body weight/min– Maximal aerobic power is 80% determined by genetics.

• Children have lower hemoglobin concentration in their blood than adults and therefore tire more easily.

• Response to Exercise: – Heart Rate increases with intensity of exercise.– Systolic pressure goes up.– Change from steady to rapid respiration = anaerobic threshold– The body cannot keep up with the oxygen demands or waste buildup.

• FIT– F requency: 3 times / week– I ntensity: (220-age)*0.7– T ime: 20 minutes in the target range

– Recently just 90 minutes of vigorous physical activity for children (9 x 10 minute blocks.

• Test with a distance run or step test.

Muscular Strength and Endurance

• Muscles are made up of muscle fibers:– Fast twitch: work quickly and briefly without oxygen

(anaerobic metabolism)– Slow twitch: Work longer and more slowly with

oxygen (aerobic metabolism)

• Proportion of musculature is genetically determined

• Proportion of muscles before puberty is same for boys and girls.

• After puberty, muscle size increases more for boys than for girls

Strength

• Definition: Maximum force applied in one effort

• Affected by neuromuscular coordination

• Training:– Before Puberty, testosterone is in limited supply so strength

training will have little benefit (except for a VERY weak child)– F: 3x / week– I: 5-10 repetitions--overload principle– T: 3x—some literature says once is efficient

• Tested with chin- ups

Endurance

• Definition: Performing a movement numerous times at less than maximum contraction.

• Tested with sit-ups

Flexibility

• Definition: Range of motion at a joint

• Joint specific

• Important to warm-up, then stretch, then do activity

• Stretch slowly, relaxed, and hold for 30 seconds– don’t bounce– watch knees, back, neck

• Tested with sit-and-reach

Other Points

• Exercise has a positive affect on body composition and bone composition

• Injuries– When skeleton is developing avoid overuse of

certain joints and unnecessary roughness. (ie. too much tennis and baseball will cause calcium deposits at the elbow)

– Break of the epiphysis (growth plate) needs to be properly treated.