Kenichi Ito - monkey man. The Japanese Kenichi Ito may call himself the fastest man on four legs . 29-year old Kenichi Ito says since he was younger people would tell him he looked like a monkey so naturally he began studying the animals. Kenichi Ito says monkey business has always been his calling. He says people teased him. Kenichi Ito, 29, monkey enthusiast, is world's fastest runner on four legs. 29-year-old Kenichi Ito from Tokyo has perfected a running style based on the movements of African monkeys, earning an entry in the Guinness.