Photo: akunamatata, Flickr

Trail running has lots of perks -- more shade, great hills for the quads and butt, soft dirt for the joints, and now, Fitsugar says research shows that trailing burns 10 percent more calories than treadmilling.

The uneven terrain is what ups the trail workout. All those extra climbs and obstacles pump up the tempo and work all sorts of muscles.

If running isn't your thing, you can walk, jog or bike your way around the outdoors. Just find yourself a trail and get to work -- try charting your courses at TrailLink, Trails.com and Trailrunner.

Another outdoorsy workout: Rock climbing. You can even take it indoors if that's more your speed.