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Chapter 12

Physical Development of Children

© Gallahue, D.L., & Ozmun, J.C.. Understanding Motor Development.McGraw-Hill

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Key Concept

The Physical Fitness of Children Has Been Assessed Through a

Variety of Laboratory and Field-based Measures, and May Be

Improved Through the Application of Appropriate Training

Techniques

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“Fitness” Defined

Physical Fitness Is a Positive State of Well-being

Influenced by Regular Physical Activity, Genetic Make-up, and Nutritional

Adequacy

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Are Children Fit? No (> obesity, < fitness scores,

sedentary lifestyles, conventional wisdom)

Yes (children are naturally active, lack of “gold standard”, apples & oranges, lack of criterion measures)

Perhaps (what do you think?)

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Components of Health-related Fitness (Table 12.2)

Aerobic endurance Muscular strength Muscular endurance Joint flexibility Body composition

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Aerobic Endurance

Max VO2 (45-55ml.Kg) Heart rate responses (Children around age

6 at rest ~80bpm, around age 10 ~70 bpm)

Measures of physical activity (activity recall, heart rate monitors, doubly labeled water, direct observation, accelerometers)

Aerobic trainability (“trigger” hypothesis)

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Muscular Strength and Endurance (Table 12.1)

Isotonic/isometric/isokinetic The Strength – Endurance

continuum Measures of Strength (Lab:

dynamometers & tensiometers, Field: internal validity?)

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Muscular Strength and Endurance (cont.)

Muscular endurance (lab: ecological validity?, field: sit-ups, push-ups, pull-ups)

Minimal sex differences Trainability (resistance training vs. weight

lifting) Training results (positive: neuromuscular

adaptation, muscle hypertrophy, negative: growth plate injuries, overuse injuries)

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Joint Flexibility Static/Dynamic flexibility (static

vs. ballistic stretching) Joint specific Girls outperform boys Preadolescent growth spurt

(bone growth precedes muscle & tendon growth)

Trainability (“use it or loose it”)

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Body Composition Proportion of lean body mass to fat

body mass Measures (Lab: hydrostatic

weighing, electrical impedance, Field: skin-fold calipers, BMI)

Sedentary lifestyles and obesity Trainability (team approach,

physical activity/nutrition education)

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Components of Motor Fitness (Table 12.3)

Movement control factors:-balance (static & dynamic)-coordination (gross motor & eye-hand)

Force production factors:-movement speed-agility/quickness-power

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Coordination Sensory-motor integration

process Boys more proficient than girls

from age 6> Measures (cable jump, hoping,

skipping, ball dribble with hands or feet)

Changes (linear throughout childhood)

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Balance Vestibular apparatus (semicircular

canals, otolith, macula) Girls more proficient up to age 7-8 Measures (Static: one foot

balances, Dynamic: walking board) Changes (linear improvements from

2-12)

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Movement Speed Reaction time & movement

time No sex differences to age 6-7,

boys faster at all later ages Measures (dashes to 20-50

meters) Changes (linear throughout

childhood)

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Agility/Quickness Speed with directional changes Minimal sex differences during early

childhood Measures (shuttle runs, side

straddle) Changes (linear for both boys and

girls, but girls level at age 13 while boys continue to improve through adolescence)

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Power Explosive strength (strength x

speed) Boys outperform girls at all ages Measures (vertical jump, long jump,

distance throw, velocity throw) Changes (linear changes - early

childhood through adolescence in boys, to 13-14 in girls)

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Concluding Concept

Although the Components of Childhood Fitness Can Be

Modified Through Training, We Need To Find Ways to Help Children Sustain Increased

Physical Activity That Are Both Purposeful and Meaningful