The bottom line is that you still need to up your body temperature, but you can do that in any number of ways. Though not unanimous, the weight of evidence suggests that dynamic stretching, not static, is superior. Static stretches can decrease your muscular output (TK description), and though that might only matter for people lifting heavy weights, it's probably not what you're going for at the beginning of your workout. If you're feeling tight, personal trainer Jessi Haggerty suggests rolling them out with a foam roller and doing some active stretching on those areas. Then, she says, "you can always build something more sports-specific into the beginning of your workout. For example, walking or running at a slower pace if you're going for a long run, or starting off your strength training circuit with lighter weights or bodyweight exercises and build up from there."