The “55″ workout

Start by doing one body-weight squat and 10 pushups. Rest for 30 seconds, and then do 2 squats and 9 pushups. Gradually work your way up to 10 squats and down to 1 pushup. You’ll complete 55 reps of each exercise by the time you’re done—and reap both the cardiovascular benefit of aerobic training and the muscular pump of a strength session.