When it's time to do this killer bottom-lifting exercise in Bar Method classes in New York City, even the leanest, strongest, most Black Swan–like students look like they're about to cry. But people have a love-hate relationship with the Pretzel. Bar Method founder Burr Leonard says it's hugely popular—probably because you feel it so intensely in your glutes, upper thigh and waist that there's no way it can't be working.
1. Sit on a soft carpet or exercise mat. Drop your right knee to the floor, aligned directly in front of your right hip. Bend that right leg to 90 degrees.
2. Lean your torso to the right side (you'll be at an angle of approximately 45 degrees, and most of your weight will be on your right hand. Keep your fingers pointing forward).
3. Slide your left leg (your "working leg") back behind you, so that your thigh is in line with or slightly behind your hip. Bend that knee to 90 degrees.
4. Lift your chest and pull in your abs.
5. Raise your left working leg off the floor an inch and hold for about 10 seconds. (Keep your left thigh next to or slightly behind your left hip.)
6. Press your left leg back (one inch) and forward (one inch) 20 times.
7. Lower your leg. Lift it again. Repeat the 10-second hold and then the 20 presses.
8. Repeat the sequence with the other leg on the opposite side.
Next: 5 ways to get a flat stomach without crunches