You often hear how stretching—whether static, isometric or dynamic—should be a focal point of every workout. Phrases like "each session takes only five minutes" and "don't miss out on the performance benefits of stretching" are constantly heard in the training room. But what do those few little motions actually do?
Want to build leg muscle? Stretching your legs pre-workout lengthens muscle tissue and increases flexibility, so you can perform a more effective Squat set. Each movement stresses the tissue of the muscles you are working. (See Stretching for Increased Muscle Size?) Those reps effectively create tiny tears in the muscle tissue. The byproduct of your work is a build-up of lactic acid.
Post-workout stretching is equally important. It floods the muscles with blood, which provides nutrients to heal those tiny tears. At the same time, the lactic acid is moved out of the tissue, reducing soreness. Not bad for five minutes of your time, right? The benefits of stretching are endless.
In my opinion, the best pre-workout method is dynamic stretching. (See Stay Loose and Ready With Dynamic Stretching.) Matt Brown of Norcal Strength and Conditioning states, "Dynamic stretching prepares the muscles for a series of exercise such as Squats or Lunges in a hamstring, quadriceps and gluteal workout. This is opposite of static stretching, where the focus is to hold a stretch for roughly 30 seconds. Dynamic stretching focuses on body weight exercises that ramp intensity and rush the muscles with blood to increase flexibility and injury prevention."
Focus on static stretching post-workout. (Read The Basics of Static Stretching.) Be attentive to your muscles. Don't take them further than they are willing to go, but be sure to feel each stretch. You will reduce your chance of developing delayed onset muscle soreness (DOMS) and be ready for your next workout.