Want to burn 200% more calories during your next cardio session? A Kansas State University study published online at ScienceDaily.com suggests training with a partner who has a capacity for exercise about 40% greater than yours. Apparently being an underdog can motivate you to outperform solo workouts.
Researchers had college aged females cycle on a stationary bike until they felt they'd put in a good workout. On a later visit, when these same subjects rode with a virtual partner, they spent 40% more time pedaling. A third workout teamed subjects with another rider in an endurance competition where the time spent exercising was pushed to about 200% of what was achieved during the first solo trial.
TIP: Scientists conducing this study suggest that training with a weight room equal or with someone who can do a lot more than you doesn't produce results like a training partner who's only slightly better. You have to realistically be able to match their effort with your best effort.