Stand with feet hip-width apart, holding a five- to eight-pound dumbbell in each hand. Take a large step forward with right leg (about three feet), then bend knee to a 90-degree angle, keeping left leg behind you, heel off the floor. Switching your weight to your left leg, bring right leg out to side so it's in line with left leg, and bend into a squat with both thighs close to parallel to the floor and arms in front of body. Push off right leg, and place it about three feet behind you, so left leg is forward and bent at 90 degrees. Return to start position. Repeat for 30 seconds, then switch legs.
Minute 9: Stair Climbers (cardio cooldown)
Run up a flight of stairs as fast as you can, then jog down. Repeat for 30 seconds. (If you don't have stairs, do the Sideways Shuffle.) Then walk in place for 30 seconds to slow your heart rate.
Minute 10: Hamstring Stretch (stretch)
Place left heel on step, and keep knee straight but not locked. Bend torso forward until you feel a stretch in the back of your left leg. Try to keep back straight. Hold for 15 seconds, then switch legs and repeat.