That was during a 6 day track event - Madison race. Today, we use the throw where we grab the partners hand and throw them into the race. When I supervised track and taught beginners, I used the old Madison push as a training exercise. The idea was to ride slowly side by side on the banking and release one hand from the bar and just slightly touch the back of the partner with a gentle push. This was done in connection with the standard bumping / contact drills.