People doing what activity came under police suspicion in the 1960s?
Today, it’s difficult to imagine the streets and parks not filled with enthusiastic joggers. However, back in the 1960s, it was very unusual to see ordinary people running, and police didn’t know how to handle the new fad. There was even one incident in 1968 when an NYC jogger was issued a ticket for "illegal use of a highway by a pedestrian.” Despite the bumpy start, by the '70s, jogging had become a legitimate, popular way to exercise.
Source: Vox