“Two more. You can do it.” I pull hard against the 45 pounds that strain my triceps as I finally grunt “twe-lve.” My arms are weak and shaky, but I make it through my third set of 12 upright rows. “OK, let’s move.” Josh Magaha, University of Kansas Recreational Services cardiovascular resistance training manager, hurries me on to leg press to begin the lower-body part of my 30-minute circuit-training workout.

I love to work out, but when things get busy and I am pressed for the time, it’s the first thing that gets kicked out of my schedule. So I went in search of the most efficient 30-minute workout for busy, time-crunched students. Here’s what I came up with.

The benefit of circuits

Circuit training is strength training done at such a pace that the heart rate is elevated within 50 to 85 percent of its max for the entirety of the workout, which is — in our case — 30 minutes. These workouts are easy to follow because they can be run by a stopwatch instead of counting, Magaha says, and circuit training promotes overall wellness by combining a cardiovascular workout with strength training.

I like to think I am in pretty good shape. I run nearly every day and lift weights regularly. Still, I could feel my increased heart rate about halfway through the circuit workout and had to admit to Magaha that I was feeling shaky.

If you only have 30 minutes you’ve got to make the most of the time you have, Magaha says. Keep your time and move quickly through the workout. “Some people will be at the gym for an hour and a half and only do four lifts,” Magaha says. “Don’t talk during your workout; talk afterwards.”

For students who only have 30 minutes to fit in a workout, the key is to be focused and efficient, says Joanna Clingingsmith, trainer at Lawrence Athletic Club, 3201 Mesa Way. Like Magaha, Clingingsmith agrees that the ideal workout includes cardiovascular and strength training with little or no rest in between so that the heart rate is elevated to give the benefit of aerobic exercise as well as strength training. Multi-joint exercises like lunges, squats or step-ups incorporate several muscle groups into one exercise, thus increasing the efficiency of the exercise. Clingingsmith recommends using multi-joint exercises for the lower body and a lift for each part of the upper body: chest, back, biceps, triceps, shoulders and abs. Do a set of 10 to 15 reps on each lift, and repeat the entire body workout three times. “This will get your heart rate up to get the benefits of aerobic exercise activity and good solid calorie burning, as well as the benefits of tightening and strengthening your muscles,” Clingingsmith says.

The circuit workouts are great for condensing muscle — not bulking up — and getting toned, says Jenny Prohaska, Leawood senior, who began circuit training two months ago. She has lost three inches around her waist and has lowered her body fat percentage several points. Prohaska circuit trains four days a week and she rotates among machines, free weights and ball exercises. If she has time, she likes to add up to 30 minutes of a cardiovascular exercise to the end of her workout. “It really gets your endorphins going and you feel fantastic after a good workout,” Prohaska says.

Skip one Friends rerun and hit the gym. You don’t have to spend hours working out for your body to benefit. Combine your strength training and cardio into a circuit-training workout to be time-efficient. See you there.