The idea of going shirtlesson any occasion can sendguys rushingto the gym to squeeze in as many last-minute workoutsas possible. But that plan isnt always the most efficientroute to take.To get you in the best shape of your life,we picked the brain of Tony Horton, the mastermind behind P90X Opens a New Window. .

The point that I like to stress with this workout is that you can do this anywhere, says Horton. He addsyou dont need to go to the gym, use equipment, or get help from a trainer.You need an imagination. If you dont have an imagination if youre not a human, if youre not near earth, and there is no gravity where you are you cannot do that routine. But if any of those things are in play, you have no excuses.

Hortonprefers doing three to sixrounds of the following exercises, never repeating the same movetwice.Here, hewalks us throughhis Simple 4, a.k.a. the No Excuses Workout, tohelp youget thebodyyou wantyear-round.

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Tony Hortons Simple 4

Three rounds is 12 exercises. It can happen in less than 20 minutes pretty easily. You go through all four, you take a short 30 second to 1-minute break, do the next four, and then you get that break, and then the next four. And then you do sixrounds that thing will last you 50 minutes if you want to do it.

Move #1: Push-ups
Take a push-upthat you can do. Do as many as you can with good form wide, narrow, feet apart, feet together, with one arm, plyometric, spinning, I dont care what it is. Just do something where you are on the deck and off your knees. Say youve got 100 pounds to lose and youve been doing push-ups on your knees forever: Get off your knees and get in a plank and hold the plank. Do little 1-inch push-ups or half-inch push-ups just something where you are forced to engage your stomach and core. You cant do that on your knees. You eliminate a critical part of the exercise. So anybody and everybody, regardless of their level, get down on the deck and do as many as you can until they get ugly.

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Move #2: Cardio
Your next move is something cardio in-place. You can do jumping jacks, you can run in place, you can march in place, you can throw punches and kicks. Whatever you want to do. Free-form it, change it up, I dont care. Everybody knows what a jumping jack and running-in-place looks like. Everybody knows what simulated jump-roping looks like. And then you can throw punches or kicks and knees if youre a mixed martial arts background for instance. Do that for 60 seconds. If you have the option to create on the spot, as long as youre working hard, thats money. And that really opens it up to a lot of people as opposed to me telling you, OK. You can do a military push-up. Go all the way down. And a lot of people cant do it, so you give them an option to do whatever they want to do.

Move #3: Legs
Youve done your upper, cardio, and now you have to do your legs. You can do walking lunges, forward lunges, step-back lunges, skipping lunges, plyometric lunges, squats. You can do isometric chair against the wall. You can do a leg raise, wall squats, you can do side lunges. I dont care, but whatever you do, the idea here with the leg exercise, which is different than the cardio exercise, is this is more muscle improvement. So with cardio, youre not jumping up and youre not going down. Youre up on your feet and youre moving its more heart and lung. Now you are going to get deeper into it with some leg movements. And you want your lunges to be deep, your squatsto be deep, and you want to be somewhere between 20 and 40 repetitions depending on the individual.

Move #4: Abs/core
Your last move is your absorcoremove. And you can do crunches,scissors, and isometric forearm planks, whatever. You can do a boat pose. You can do anything where you are either on your back, on your butt, or on your front side or belly. Typically, if youre going to do an isometric on your forearm or plank-type movement, try to hang in there for 45 to 60 seconds. If youre going to do something on your back or your butt where youre doing crunches or you are doing sit-ups or crunches or scissors or flutter-kicks, you want to get somewhere between the 20- and 40-rep range. Everybody is different. Some people are going to burn out right at 20. Some are going to go all the way to 40.

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How Horton Does It:
Whenever I do this Simple 4, I never repeat the same exercise twice.The first time, Ill do military, second time Ill do wide push-ups, third time Ill do side-to-side plyometrics. I usually like the third round the hardest. And the same thing: The first round, Ill do standard jumping jacks, mellow. Then the second time around, Ill sprint in place and get my heart rate up. And the third round, Ill do jab-cross-downstrike sprawls, so Ill get pretty heavy into the martial arts on the third round of cardio.

And on the leg stuff, Ill start out with basic deep squats. And maybe the second round, Ill go to plyometric lunges. On the third round, Ill do full single-leg deep jump squats, and thats really only on one leg, so its, like, 10 or 15 on one leg, 10 or 15 on the other leg. So Im always turning up the volume with every one. And then once you do that for about three or fourweeks, then you go to fourrounds, then you go to fiverounds, then go to sixrounds. You do sixrounds of that, and youll get the best workout of your life.