One of the program’s main appeals is its versatile, do-anywhere set-up. You can follow along via DVD in your living room, and most of the workouts use body-weight resistance (a few call for resistance bands or dumbbells), so you don’t need any fancy equipment. P90X touts what it calls “muscle confusion” as the centerpiece to its effectiveness: By doing multiple variations of short, high-intensity moves, the body never gets settled into a routine and therefore theoretically will never plateau (that annoying part of exercise where you’re doing the same workout as always but no longer seeing improvements in your fitness because your body has gotten used to the effort). Probably the biggest caveat with P90X is the relatively high level of base fitness you need before initiating the program. The system call for 6 days a week of workouts, a single session can last for more than an hour, and there is very little rest built into the workouts — part of its success comes from the fact you are constantly working hard. So if you’re looking for a couch-to-5k type of deal, this ain’t it. But unlike other 20-minute workouts, if you’re reasonably fit and looking to take things to the next level, this one’s for you. While the official P90X site includes a nutritional plan along with the exercises, let’s just say it follows basic sensible eating guidelines, with an emphasis on lean protein, fewer fats, and more complex carbs. So, you know, eat like the pro athlete you wish you were, and follow the routine below — a similar workout to the official plyometrics P90X one — to get fitter and stronger in 90 days.

The 20-Minute P90X Starter Workout

Do each of the exercises below as a circuit. Repeat the full circuit three times.

Jump Squats

Squat. Jump. Repeat 20 times.

Running Lunges

Lunge forward with each leg in big, deep steps four times. On the fourth lunge, swing your back leg forward and jump vertically like you’re shooting hoops. Return to lunging. Do 10 times.

Side Jumps

Cross your left leg over your right leg, then swing both legs out to the right side, knees bent, as you jump the air. 10 side step-jumps right, then 10 to the left.

Swing-Overs

Face a chair or bench so that you are standing just to the left of an object. Raise your right leg and swing it over the top of the chair. Shift your weight to the right side and swing your left leg over to follow. Reverse direction. Do 20 swing-overs.

Box Jumps

Face the bench or chair again (make sure it’s sturdy). Bend knees, then spring up onto the platform or seat. Jump back down. Go up and down 20 times.

Twist Jumps

Bend knees and wind arms up over to the left side. Release arms and jump to the right, twisting your body 180 degrees. Bend knees and wind arms to the right side. Release and jump a half-turn to the left. Do 10 twist-jumps to both sides.

Squat Jacks

Two minutes of jumping jacks, except instead of landing normally, every time your feet touch the ground, you squat.

High-Knee March

Two minutes of marching in place, raising your knees as high as you can with each step.

Leapfrog

Like the game you played as a kid, this exercise starts with you crouching down, fingertips touching the floor. Stretch your arms out in front of you, then spring off your legs to catapult your body forward and into the starting crouch position. 10 leapfrogs, then turn around and do 10 back to the start.

Fast-High Feet

Like a football drill, you start this exercise by taking mini, rapid steps forward for 10 seconds, moving your feet as fast as you can. Then take slow, giant steps backward for 10 seconds, lifting your knee as high as possible with each step. Do three times.

Standing High-Knee Jump

Stand, bend knees slightly, jump in air tucking knees to chest. 20 jumps.

Square Run

Place a bath towel flat on the floor. Keeping your head and upper body facing forward, take extremely small, fast steps and run your way around the towel perimeter. Do for one minute, then switch direction for one minute, maintaining a forward-facing upper body the entire time.