Physical Development

Physical Development 

How do our bodies change? 

  • Growth in middle childhood and adolescence 

  • Motor development 

  • Body growth 

  • Puberty 

  • The HPG axis 

  • The physical changes of puberty 

Motor development in middle childhood 

  • Motor Skills: Intentional and voluntary movements carried out by our bodies 

  • Gross: larger body muscles (walking/running)  

  • Fine: smaller muscle groups (hand eye coordination, typing/writing) 

  • Physical and cognitive, knowing when and how to jump 

  • Gross motor development 

  • You basically just get better at moving 

  • Speed and complexity  

  • Fine motor development: Writing 

  • Can print the alphabet, names, and numbers by 6 

  • Legibility of writing improves 

  • Younger children are typically using their whole arm to write, while older children have learned to use their hands and wrist to write.  

  • Sex differences in motor skills  

  • Female: fine motor skills, balance, agility (girls have smaller fingers, girl are typically socialized to be neater)  

  • Male: gross motor skills, e.g., throwing, kicking (body size and experience, male babies tend to be more active, even before birth) 

  • Generally, differences are minimal 

Body Growth in middle childhood 

  • Physical growth continues at a slow, regular pace 

  • Bones lengthen and broaden  

  • Lower body grows faster than upper body 

  • Female children begin to grow faster than male children around age 8 

How do you change during puberty? 

  • Body hair, boobs, acne, face/body shape, voice, height, feet, hair darker, emotions, BO, period, ejaculation, etc. (overall hormonal changes) 

Puberty  

  • A set of hormonal and physical changes that occur as individuals pass from childhood to adulthood 

  • Hormonal changes during puberty 

  • HPG axis 

  • Hypothalamus, pituitary gland, gonads 

  • Each stimulates or inhibits another part of the axis 

  • Results in regulation of sex hormone levels 

  • Add in graphic later 

 

  • HPG is like a thermostat 

  • HPG is active early in life 

  • But something triggers it  

  • Kisspeptin 

  • New levels of testosterone, estrogen -> adrenarche 

  • Hormonal changes underly many physical and psychological changes of puberty 

  • Physical changes during puberty  

  • 1. Rapid growth acceleration 

  • Male: at peak growth velocity 4 in/yr 

  • Female: at peak growth velocity 3.5 in/yr 

  • 2. Primary Sex Characteristics- change in uterus 

  • 3. Secondary Sex Characteristics- growth of breasts, muscle change 

  • Semenarche: First ejaculation 

  • Menarche: First mensuration 

  • Do not indicate the start of puberty 

  • Tanner Scale- scale of puberty changes in genitals 

  • The secular trend 

  • As a species, we are getting bigger 

  • As a species, we are starting puberty earlier 

  • Due to improvements in health and nutrition