1. Shorten rest periods
Progressively shaving seconds off your rest period can help to raise your metabolism. Just don't go too low, warns Joe Stankowski, C.P.T., a trainer in Grand Rapids, MI. "You need a minimum of 30 seconds' rest or you risk burning out," he says. The one exception: circuit training, which requires no rest between sets.
2. Train the entire body
3. Alternate sets
Do a set of a lower-body exercise followed by an upper-body one, such as a squat and then a row. This way, one muscle group has time to recover while you train another one.
4. Increase lifting speed
You can burn more calories by doing explosive exercises like plyo pushups (during which you push yourself into the air) and box jumps, or by using lighter weights and lifting them more explosively on the upward phase of the movement.
5. Decrease reps
Most guys' workouts are based around the idea of 10 reps per set. But, according to Jim Smith, C.S.C.S., a strength coach in Sayre, PA, you'll get a much bigger spike in metabolism by reducing your reps and tacking on an additional set. Try sets of six to eight reps.