Are you still thinking about a New Year’s resolution to work out more? Research shows that exercising with a buddy can give you both mental and physical boosts.

In fact, under the right conditions, the intensity and duration of exercise among workout partners can be more than twice that of solo efforts.

Here's how to make the most of the workout buddy system:

• Studies show that the best exercise partner is someone about 40 percent more fit than you are -- this will motivate you to work out longer and harder. It's called the "Kohler effect" -- the ability to perform at a higher level when working with a stronger person.
• But if you're a novice, you don't want someone so far advanced that you could hurt yourself trying to keep up. If you're in a fitness class and need to pair up, choose a slightly more experienced participant.
• If you like exercising at home or if logistics make it hard for you and your buddy to get out of the house at the same time, consider being internet partners -- you can exercise simultaneously through a video chat.
• Although a human partner is the better motivator, if you can't find one, try a virtual buddy. Many fitness apps let you create this motivational helper.
• Finally, if you're the one providing the motivation, here's a surprising finding to keep in mind: motivate through actions, not words. Research found that when exercising with someone who is slightly better than they are, participants exercised longer when that person was not verbally encouraging them.