Bikini body boot camp with David Kirsch

Bend forward from the waist, keeping your legs and your gaze straight ahead. Keep your back flat. Once your body is perpendicular, rise back up as you exhale. Add a knee bend to the movement. Do the move as usual but this time, once your torso is parallel to the floor, bend your knees and lower your butt toward the floor, finishing the movement by straightening your legs and standing up at the same time. The second part of the move - the knee bend - must be done slowly and carefully. Make sure you engage your glutes throughout the move by sticking your butt out as much as possible. That will take the pressure off your knees.

Sit into a squatting position with your hands behind your head, your knees aligned with your toes and your butt sticking back as far as you can go. Keep your core tight and walk forward while pushing off with each heel. If you perform this correctly you'll look like a platypus - and your glutes and thighs will be on fire.

Not everyone can do the platypus. If you have the strength and coordination to do the move, it's a great quad and glute burner. Make sure to sit back on your heels. Do not step too far forward or you'll stress your trailing knee.

If your lower back hurts during this move, limit your range of motion and be sure to disengage your hip flexors. Additionally, be sure to tighten your abs and keep them contracted throughout the movement.

Try the following punches, interpersed with some knee bends as if you were ducking an incoming punch from your shadow.

Crossover: Stand with your abs tight and your back flat. Punch your left fist out diagonally, ending at torso level in front of your right ribs. Pull back and repeat on the other side.

Uppercut: with your left elbow against your ribs and your palm turned up, punch in an upward motion, as if you were punching someone in the stomach and trying to lift him off the ground with your fist. Pull back and repeat on the other side.

Hooks: bring your bent left arm up so that it is parallel with the floor and punch with a hooking motion as if you were trying to clock someone on the side of the jaw. Pull back and repeat on the other side.