Physical Growth I The course of physical growth

Physical Growth I. The course of physical growth A. Growth curves and physical growth 1. Distance curve 2. Velocity curve 3. Growth curves for organs B. Changes in body proportions 1. Cephalo-caudal development 2. Proximo-distal development C. Continuous versus episodic growth II. Psychological reactions to physical growth A. Puberty – reactions to physical maturation 1. Reactions of boys/men 2. Reactions of girls/women B. Early versus late maturation 1. Effects on adolescent adjustment 2. Why is maturational timing important?

Distal Growth Curves Distal growth curves: • Plots the growth of particular body dimension each year • Can determine interesting facts about physical growth • Plot boys and girls separately, see sex differences • Ex. In infancy, height and weight comparable • Age 11, see reversal in trend – girls shoot past boys • Advantage short-lived – reverses again by 14

Velocity Curve Velocity curve: • Plots absolute growth at yearly intervals • Better than distance curve at identifying timing of growth spurts • See same graph of height gain • Timing of growth spurts much more evident

Growth Curves for Body Organs Velocity curves for body organs: • Plotted in terms of percent of adult size • See variety of patterns for different organs • Brain and skull mature quite quickly • Genital more slowly, then growth spurt in adolescence • Lymphoid system overgrows, then shrinks

Changes in Body Proportions Cephalo-caudal development: • Growth occurs from the head downwards • In infancy upper part of body grows first • Lower part of body catches up in adolescence Proximo-distal development: • Growth begins near center of body axis • Trunk of body grows before upper arms • Upper arms grow before lower arms and hands

Continuous vs. Episodic Growth

Psychological Reactions to Physical Growth Puberty: The transition to adulthood • Physical changes and development • Psychological impact of puberty • Girl reactions to first menarche • Early studies • Importance of advance information • Boys reaction to first spermarche The importance of early versus late maturation • Berkeley study of maturational timing • Early versus late maturing boys • Early versus late maturing girls • Explanations for maturational timing effects