This is interesting, esp. as schools are cutting down recess/playtime/phys ed to nothing, and the nutritional value of the food kids eat in schools is completely inadequate. Brains can't work well if the rest of the body isn't being taken care of.
Kids physically develop at slightly different rates. There are, however, milestones to watch for at certain ages. Keeping track of your child’s progress in physical coordination at different ages can help reveal potential issues.