Jumpstart Your Fat-Burning Engine

5 quick steps to losing big

Monotony kills motivation. Here's the opposite of that -- an explosive, weights-free fat-burning workout of changeups and gear shifting that makes you leaner and more athletic. There's very little downtime, "so you'll improve cardiovascular fitness without compromising your strength or muscle," says Robert dos Remedios, C.S.C.S., director of speed, strength, and conditioning at College of the Canyons, in Santa Clarita, California.

Do 10 repetitions of each move, and proceed swiftly from one exercise to the next; your setup should take no more than 10 seconds. Complete all five exercises, rest for 1 to 2 minutes, and repeat the drill. Perform a total of three or four rounds.

Tuck Jump

Stand with your feet shoulder-width apart and your knees slightly bent. Jump straight up as high as you can and bring your knees toward your chest. Land on the balls of your feet with your knees slightly bent and quickly go into your next jump.

Squat Jump

Stand with your feet slightly more than shoulder-width apart and your fingers laced behind your head. Bend at the knees to lower yourself until your thighs are parallel to the floor, then jump up as high as you can. Sink directly into the next squat without pausing.

Power Skip

Don't worry: This looks much cooler than traditional skipping. You'll propel yourself as high as you can with each skip by driving your knee up into the air. As you punch each knee up, swing your opposite hand upward to get as much vertical lift as possible.

Zigzag Bound

Think about lengthening your stride as much as possible. Drive one leg into the ground to push off forcefully and lift your opposite knee high in the air as you surge forward. Propel yourself upward, forward, and slightly laterally so that you bound forward and to the outside.

Stick Landing

Stand with your feet shoulder-width apart, hands beside your thighs. Jump and land with your knees bent and your butt and hips back. Try to land on the front two-thirds of your feet, with your heels just off the ground. Hold for 2 seconds before standing to perform your next jump.