Exercise machines weren't created to punish guys who eat too much. That's what diets are for. But men spend hours, day after day, churning their arms and legs and waiting for the StairMaster or treadmill to make their bellies vanish. The result: They make it about as far as the average rat. But your machine workout doesn't have to be a road—or row—to nowhere. "By decreasing the duration and varying the intensity of your fat burning exercise sessions, you'll get better results in less time," says Chris Carmichael, founder of Carmichael Training Systems and coach to Lance Armstrong.
Try our guide to the five most popular exercise machines, with a high-intensity 20-minute workout geared for each. Your goals: Bust your exercise rut, and your gut, in record time.
The Knee Saver
a.k.a. Elliptical Trainer
Burn Rate: 13 calories per minute
The Benefit: Researchers at the University of Mississippi found that elliptical trainers provide the same cardiovascular benefits as treadmill running, without the impact on your joints. So they're a perfect solution if you're a runner who wants to stay in race shape without excessive pounding to your ankles, knees and hips.
Do It Right: "Instead of holding on to handles, pump your arms as if you were running," says Kerri O'Brien, C.S.C.S., a trainer in Phoenix. It improves your balance, which will help you whether you're running 2.6 miles or 26.2.
The 20-minute Fat-burner: Try this "alternating interval" fat burning exercise workout from Lance Watson, a coach of Canada's Olympic triathlon team. By alternating between levels of high resistance and those of high speed, you'll be able to work at a higher relative intensity for a longer time. Warm up, then increase the machine's resistance level until you're striding at 80 percent of your full effort. After two minutes, lower the resistance to the level you used during your warmup, but increase your stride rate so that you're still exercising at 80 percent of your full effort. Continue alternating between a high resistance and a fast stride every two minutes for a total of 20 minutes.
The Total-body Builder
a.k.a. Rowing Machine
Burn Rate: 11 calories per minute
The Benefit: "Rowing machines provide the best total-body workout of any cardio machine," says U.S. Olympic rowing coach Mike Teti. This is because they require equal effort from both your lower and your upper body, which could lead to greater gains in overall cardiovascular fitness.
Do It Right: On the back stroke, your knees should be almost completely straight before you squeeze your shoulder blades together and pull the handle to your sternum. Your back should stay in its naturally arched position during the entire movement. Got it? Now sign up with the Million Meter Club at www.conceptII.com. Record your distance online after every rowing session and see how you rank against more than 3,700 other club members. Stay motivated by finishing your second million in less time.
The 20-minute Fat-burner: Try Teti's routine. It's designed to max out your muscles during each interval, while the recovery periods help increase the efficiency of this fat burning exercise routine. Set the rowing machine at a resistance of four. Then perform sets of 10, 15, and 20 power strokes--pulling the handle to your torso as fast and as hard as you can. Separate the power strokes with 60 seconds of easy rowing at about 50 percent of your full effort. Repeat the cycle until you've rowed for 20 minutes.