If you want a simple tip to make your 2010 workouts more effective than those of 2009, here it is in two words: workout harder . I'm always amazed at the average intensity I see when I go to the gym. A typical observed weightlifting workout involves 8-10 reps at too low a weight, followed by 4-5 minutes of sitting around (waiting for your heart rate to drop from 100 to 80?), repeat, move on to another exercise, etc. Yes, it's better to be in the gym doing something than nothing, but these workouts aren't really doing much for you. When I started working out seriously back in July or so, I made circuit workouts a regular part of my routine. I choose two exercises that work different muscle groups (for example, pull-ups and lunges), and do supersets (do one set of one exercise, then move immediately to the next) with one minute rests in between. I work out hard enough that my heart is really pumping by the end of each superset. The one minute rest is just enough to bring my...