If you want to keep your legs covered but prefer more form-fitting pants that move with you, opt for a pair of quality leggings or tights that will hold up well in the outdoors. Spandex yoga or running tights are great options for day hikes, or even overnight backpacking trips. If you're going on a multi-day backcountry outing, though, you may want to go for something heavier-duty, like tights designed for triathlons. For cold weather hikes, you may also want to wear this kind of bottom as a base layer under traditional hiking pants.