Motor development refers to gross motor skills, which are big muscles. Things like running, walking, catching, kicking, throwing a ball. As well as fine motor skills, which are more your intrinsic hand muscles for object manipulation. Typically, by the age of six and seven, your child should be able to move their body to music, to a beat.
They should also be able to do somersaults and simple gymnastics. They should be able to ride a bicycle independently (with a helmet). They should also be able to engage in sports. They have very good hand-eye coordination at this point and really good balance. So this is the age where you really want to get them involved in organized sports, and go with what they like. And if they're not sure what they like, introduce them to a lot of sports.
For example, it could be basketball. It could baseball, softball. It could be tennis. It could be ping pong. Getting them active is great. It works on so many of their skills and helps with attention, focus and any sports related activity is really great for a child's self-esteem and self-confidence, which is huge at this age.