We’ve all seen them: Sweaty-faced people, huffing for breath and summoning all their energy to shuffle from point A to point B. The clothes they wear manage to combine all the skin tightness of a Cirque de Soleil costume and the bright colors of a ’90s sitcom into one tremendous lycra offense against fashion. Up close, you can hear them throw around weird terms such as "negative splits," "overpronation" and "Asics." They’re outside your place of business, your child’s school, even your house.