Take it to the Next Level Circuit Training:

Incorporate circuit training into your fitness routine for a surefire way to reach the next level of endurance, strength and weight loss. Instead of spending 30-60 minutes doing aerobics and another 30-60 minutes doing strength training, combine the two for a more robust workout. Take the boredom out of your routine by spending five minutes on aerobics (standard machines such as treadmill, stair stepper, stair climber, bicycle, elliptical trainer, cross trainer) then alternate with five minutes of strength training (free weights, weight machines, rubber bands.)