Exactly how this top trainer spends 30 minutes at the gym

Ever looked at a trainer's body and thought, I wonder what they do? We wanted answers, so we asked one of our favorite trainers—certified strength and conditioning specialist Rob Sulaver, founder and CEO of Bandana Training and founding trainer of NYC boxing hotspot Rumble—to dish on his exact gym routine when he's pressed for time.

Don't get tripped up by the name because they're actually incredibly simple. A complex is just a type of circuit training that utilizes one piece of equipment—in my usual case, dumbbells—so you can move immediately from one exercise to the next with little or no break in between. When you don't have to stop to switch out your weights or grab new equipment, you keep your heart rate up and fatigue your muscles in minimal time.

But to do a complex right, you have to have the moves clearly strung out in your head (again, so you don't have to stop). I like to do these six moves: dumbbell drop lunge (six reps per side), dumbbell thruster (eight reps), dumbbell Romanian deadlift (eight reps), dumbbell renegade row (six reps per side), pushups (eight reps), and mountain climbers (20 reps per side). (The Slim, Sexy, Strong Workout DVD is the fast, flexible workout you've been waiting for!)

Before I begin, I always start with a quick warm-up. I'll spend a few minutes foam rolling, then do some dynamic stretching—my favorite stretches are wall slides (10 reps), world's greatest (imagine a revolved lunge in yoga, three reps per side), and inchworms (three reps per side). Then I'll run through the entire complex doing three or four reps of each exercise with a light dumbbell. If everything feels good and easy, I bump up the weight and bang out my first set.

I don't rest at all between exercises—it's all about that heart rate! But after I complete the entire complex, I rest for 20 to 30 seconds before I start the second set. I usually time the entire set, including the rest period, and record that number. Then when I repeat my workout next week, I try to reduce that number. So for example, let's say the first set (including rest) took me two minutes and 15 seconds. From there, I'll set my interval timer to 2:15 and expect to start each new set when that puppy goes off. In 18 minutes, I can get through eight sets—which is a ton of work in such a short amount of time.

I don't mess with my music once my workout has started (it pays to create a killer playlist before you begin, deleting any songs you know you'll want to skip). I sip water only when I need it (perhaps between sets). My goal is to get through every exercise as quickly as I can with awesome form for every rep.

Think I'm done? Not quite yet. I like a good finisher to burn out whatever I've got left. I hit the battle ropes for a final total-body blast. Then bam! Done.