Hi again, My other message regarding this subject generated several replies but unfortunately the item so far were not what I was looking for. So... maybe a better description is in order.
The devices I saw were long leaf springs that were joined together at one end sorta like a "V" The one free end was a rubber pad that was in contact with the pavement, and the other end was strapped? to the person's foot. Theapex of the "V" was to the rear and the open end was in front. There was a pair, one for each foot. The person would run with very large strides. They raised the person about 2 feet high off the ground. Supposedly they provided good exercise as well as allowing one to really cover a lot of ground. I thought the name was something like "Striders" but no matter what modifiers I used with that name it never came up in GOOGLE.