3.4 middle childhood physical development

how much children typically grow a year in middle childhood

2 inches

7.5 lbs/yr

secular trend in physical growth

the pattern that each generation is taller and heavier than the pervious one, mainly due to better health and nutrition

how cortex matures during childhood 

it matures back to front

parietal and occipital lobes peak in childhood

frontal and temporal lobes mature later 

how long the hippocampus continues growing 

increases in size into adolescence supporting memory development 

adhd

neurodevelopment disorder involving 2 dimensions

1) inattention

2) hyperactivity-impulsivity

inattention - adhd

difficulty paying attention to details, disorganization, careless mistakes, failure to complete tasks

hyperactivity-impulsivity - adhd 

excessive movement/talking, interrupting, intruding, difficulty waiting 

adhd heritability

0.7-0.8

strongly runs in families

environmental risks for adhd

fetal alcohol exposure, lead, maternal smoking

brain deficits seen in adhd 

delays/deficits in executive function systems, with some prefrontal brain areas smaller or less functional 

4 cognitive problems contributing to adhd

1) executive function deficits

2) delay aversion (difficulty waiting)

3) state dysregulation (trouble staying alert/calm)

4) emotion regulation problems

dynamic systems theory

motor skills develop through interaction of:

-movement capabilities

-gender differences

-brain maturation

-motivation

-practice opportunities

pediatric inactivity triad 

1) exercise deficit disorder

2) pediatric dynapenia (low muscle strength)

3) physical illiteracy (poor movement skills)

how much activity kids need daily

60 minutes of moderate-vigorous activity

positive outcomes of organized sports

better skills, confidence, social development, physical health

motives for sport participation 

better skills, confidence, social development, and physical health

arguments for specialization

10-year rule

power law of practice (more practice → better expertise)

arguments for diversification

better long term performance, fewer injuries, longer interest

how much sleep children need 

9-11 hours, most get less than 7.5

what happens with poor-quality sleep

poor cognition, behavior problems, less emotional regulation

what affects children’s sleep

family stress and screen time

leading cause of death for ages 1-14

unintentional injuries 

common injuries for ages 5-14

falls, being stuck, environmental accidents, motor vehicles

height differences across generations refer to

secular trend in physical growth

difficulty waiting or delaying responses is called 

delay aversion 

feature that explains temporary instability while learning a new skill

motor system becomes unstable, then self organizes into a new pattern

rules that explains needing more practice to keep improving

power law of practice

-progress slows, requiring more practice for gains

a child who wakes often at night is likely to show

less sustained attention and more behavior problems