Movements that cross the body’s mid-line (an imaginary line as if drawn straight from your nose to the ground) activate growth and strengthen the corpus callosum. The corpus callosum is the nerve pathway between the two brain hemispheres of the cerebrum. Movement also helps to build the capacities that allow full sensory access from both sides of the body.
Communication between the hemispheres allows the development of skills such as reading, which uses both sides of the brain. The left hemisphere is used to sound out the word and analyze thought while the right hemisphere remembers sight words and visualizes what the author is saying.