Physical Development

Objective

• Summarize the changes in physical, brain, and motor development in middle childhood and middle adolescence.

Theories of Physical Development

• Genetic Perspective• Behavioral Genetics• Environmental Development Theory• Biological Perspective

Genetic Perspective

• Most development is determined by the child’s genes. The environmental influence is small.

• Ex. Physical similarities between siblings

Behavioral Genetics

• Use twin and adoption studies to demonstrate that all behavioral, intellectual, and personality traits are to some extent influence by genetic predisposition.

• Ex. Difference and similarities due to shared and non shared environments.

Behavioral Genetics

Shared Non-shared environment

The effects of non-shared environment are greater.

Environmental Development Theory

• Genetic based theory that hold that current pre-dispositions or behaviors are adaptive for ancestors millions of years ago.

• Ex. Stressful early family environment leads to early puberty for girls.

Biologic Perspective

• Recognizes the role of genetics, but places greater emphasis of biological structures and children’s functioning.

• Developmental patterns are studied and explained by examining hormonal functioning, brain maturation, brain chemistry, and physiologic

Middle Childhood & AdolescentDevelopment

What was puberty like for you?

In middle childhood and adolescence, developmental change occurs in:

– Physical development– Motor development– Brain development

By the end of middle childhood, children engage in activities that require:

– Fine motor coordination– Sustained attention– Improved balance

Physical changes in adolescence include:

– Physical growth– Changes in strength and speed– Brain development

Physical Changes During Middle Childhood

• Steady growth in body size from age 8-12• Gain 2-3 inches in height and 4-6 pounds in

weight per year • After age 13, when boys begin puberty they

surpass girls both height and weight• Growth rates can vary based on genetic histories,

ethnic background, illness, and other factors• Girls between the age of 8 and 12 are entering

puberty earlier

Secular Trend

• Children in almost all areas of the world are taller and heavier

Reason• Evolutionary – tallness genes are selected• Environment – improvement in life

Changes in Body Proportions in Middle Childhood

• Increase in body proportion• Stature – total height which is head and neck

length, trunk length, and leg length• Leg length increases more rapidly followed by

the trunk and then the head and neck• Rapid growth of hands, feet and limbs• Growth in jawbone growth and teeth eruption

(braces?)• Facial growth – loss of the baby face

Skeletal Development

• Hardening and fusion of the bones– Things that effect bone growth (lack of calcium in

diet, soft drinks, alabolic steriods, inactivity)– 90% of skeletal mass is developed by age 18

Body Fat Levels and Muscle Mass

• By the end of adolescence, body fat accounts fro 27% of total body weight in girls and 16% in boys.

• Increase in muscle mass• Obesity has increased in US in past 2 decades

Major Physical Changes in Middle Adolescent

• Transition from infertility to fertility• Sexual maturation• Changes in body size, shape, & composition –

Growth spurt• Increase hormonal production (gonadarche)• Development of secondary sex characteristics

Physical Development in Middle Adolescence

• Girls start puberty 1-2 year earlier than boys• Boys voice deepens• Increase in facial hair in boys• Increase in height & body weight

Maturational-deviance hypothesis

• Adolescents who are off-time will show greater adjustment problems.

• Girls who mature early have the most difficulty time adjust to change. Physical change does not match cognitive, social, and emotional change.

• Early maturing boys experience more anxiety and hostility

• Late maturing boys have more psychopathology

Brain

• Synaptic pruning and dendritic branching, discrimination, becoming more integrated

• During adolescence, there is growth spurts in specific regions of the brain

• Grey matter deceases during adolescence• Peaking of synaptic connections• Synaptic pruning• More efficient learning capability• Learning a language up to 15• Maturation of the prefrontal lobe

Brain

• Exposing adolescents to different and stimulating experiences can change the makeup of the brain significantly.

• Research shows that negative influence (drugs, violence, stress, poverty) can have a long term effect on the brain.

Motor Skill Development

In what motor activities did you excel during adolescence?

Middle Childhood

• Improvement in gross motor skills– Running – longer strides– Jumping – vertical jumping abilty– Thowing – throwing accuracy and distance– Balance – stand on one foot• Improvement in fine motor skills

Perceptional-Motor

• Greater reliance on visual perception• Can use multiple senses to process

information• Can discriminate more among the senses• Lateral dominance• More accurate perception of moving things

Motor Skills in Middle Adolescence

• Period of awkwardness for some boys• Better at physical activities• Improvement in intermodal coordination• Can block out distractions• Stronger, fast, increase in endurance,

steadiness

Application

• How can you use this knowledge of adolescent development to address the needs of adolescents?

• Create a program/assignment in which you help promote the development of adolescence.