feet elevated would be harder most of the time.. because that would essentially be an inclined bench press movement.. more sholders and less pectoral.. but i think her feet were just elevated because her hands were on the elevated bar things too, making it essentially a flat pushup.. the elevation, however, would make it easier to see that her elbows were going down to perpendicular which is important in a competition.. anyway that's pretty impressive, especially for a girl. although she probably weighs 100-115 lbs, so it would be a lot easier for her than a 150+ lb guy..
I could do 75-90 without stopping when I was in NROTC in college.. now I just bench press normally and focus on poundages/size instead of muscular endurance (which is really just for showing off how many pushups you can do)