"For toddlers, basic movement skills such as running, jumping, throwing and kicking do not just appear because a child grows older, but emerge from an interaction between hereditary potential and movement experiences. These behaviours are also clearly influenced by the environment. For instance, “a child who does not have access to stairs may be delayed in stair climbing and a child who is discouraged from bouncing and chasing balls may lag in hand-eye coordination."
(National Association for Sport and Physical Education Washington, D.C., February 6, 2002 )