From sitting up on their own to throwing a ball, children gradually develop the physical skills needed for their adult lives. Physical development includes both growth and the ability to use muscles and body parts for particular skills. Both gross (large muscle movements) and fine (small movements) motor skills contribute to physical development, and children often learn a set of skills by a certain age.
Fine motor skills are things done with your hands, including imitating actions with objects, coloring a picture, grasping a pencil for writing, painting, typing, texting, playing the piano, etc.
Gross motor skills involve the large muscles of the body that enable such functions as jumping, walking, kicking, sitting upright, lifting, bending, crawling, throwing a ball, and catching a ball.