Knight has that right - 57 minutes of nonstop sweat at the bar, on the ball or on the floor.
"It's difficult but rewarding, and you feel it the next day and I see change already in a few weeks," said student Victoria Pavia.
TV host Kelly Ripa and actress Kim Raver earned their rockin' bodies at Physique 57 New York City. In L.A., the new location offers bar classes sun up to sun down, and there's even a celebrity entrance.
Hanging on to the bar is deceiving. Make no mistake - this class is hard. They pick on their minor muscles and the major muscles and fatigue them to the point of failure. But that's a good thing.
"You're staying in one little area, and you overload your muscles to where ... smaller intricate muscles want to help out," Knight said.
Since minor muscles are not used to helping, most students find they're sore.
"Actually what hurt the most was my 'tushie' the day after because it really works your core and your seat. It hurts, but it's worth it," said student Ariane Sommer.
The program was designed over 40 years ago by ballerina Lottie Berk and her orthopedic surgeon after she was injured in a car accident. Since then, many find the format a great way to lengthen and strengthen.
"You're going to be doing some exercises that you've never felt before, you're going to be working muscle groups that you've never really ever thought existed, so you really need to pace yourself," said fitness expert Tracey Mallet. "If you fatigue it too much, the lactic acid builds up in the muscle, and then it fatigues it and it inhibits it to work any further."
Look for a bar class offering stretch, strength and a bit of dance movement for a fusion of fun and cardio release.
A Physique 57 class is $30, with monthly specials on unlimited classes. If the Beverly Hills location is too far away, you can buy a DVD for $24.95.