If you can't go to a gym, try this body-weight circuit by Mark McLaughlin, the founder of Performance Training Center, in Beaverton, Oregon. Repeat the four exercises as many times as you can within the time limit, resting 30 seconds between each. To maximize fat burning, avoid resting between exercises.
1 Pushup Place two dumbbells about shoulder-width apart on the floor. Grab them with your palms facing each other. Start in the up position of a pushup, your body forming a straight line from shoulders to ankles. Lower yourself, hold at the bottom for 1 second, and then push back up. Do 10 to 20.
2 Lunge Stand and take a large step forward. Your front thigh should be parallel to the floor and your back knee just off the floor. Return to a standing position. Repeat with your other leg. That's 1 rep. Do 10 to 20.
3 Chinup Grip a bar with your hands shoulder-width apart and your palms facing you. Pull up until your chest reaches the bar. Hold the position for 3 seconds, and then take 5 to 6 seconds to lower yourself. Do 5 to 15.
4 Plank Assume a pushup position, but with your elbows bent and your weight resting on your forearms. Your body should form a straight line. Brace your abs as if you're about to be punched in the gut. Hold for 30 to 90 seconds.