Yes. Did some English horseriding when I was younger. It involves very active maneuvers, including one that requires you to be able to lift your weight off the saddle using your thighs in brisk, repetitive fashion and using only the stirrups and horn (if needed) as leverage.  I don't think this chick has experiencing doing anything like that under her own strength (unless it involved getting the last cookie off the high shelf, teehee). Not to say Western-style riding doesn't involve a great deal of core strength, but I think this obeast was expecting a tea cup ride.