Among my treadling friends, there are many different styles. Some use one foot, others use their right foot at the front of the treadle pedal, with their left foot at the back, still others use their left foot at the front of the pedal and their right at the back. I plant both feet in the middle of the pedal, and use them simultaneously, so they get the same amount of exercise. I am taking a break from practice for a few minutes, after picking out an entire feather--forgot to put the presser foot down when I started, and that just doesn't work.
Pat in Rockport, TX