First, let's address one common misconception: stretching is NOT a warm-up activity! Stretching is an activity generally performed during or after an exercise. Many people confuse warming up with stretching. While dynamic stretching may supplement your warm-up routine, you generally never want to stretch cold muscles.
So, when are you supposed to stretch? After (or maybe even during) your workout, when your body and muscles are warmed up. Stretching after a workout is often preferred as this provides a perfect opportunity to lengthen all those tight, contracted muscles that result from exercising. Stretching after a workout loosens those contracted muscles and allows them to return to their more elongated state.
What are some good guidelines for stretching? We've already touched on one already, but here are some more:
WARM UP FIRST
Make sure your body is warmed up. Stretch at the end of your workout and pull those tight muscles back out to their normal length. They will still be firm and over time you may start to notice your overall muscle tone improving. In other words, you'll look flexed even when you're not flexing!
WORK WITH BIG MUSCLE GROUPS FIRST
Just like with resistance training, start your stretching session with the big muscle groups: legs, hips, and back. The added benefit is - if you're like most people, these are the areas that can benefit the most because they are the tightest. Hitting them first ensures that you stretch them every time you practice flexibility training.
STRETCH SLOWLY AND SMOOTHLY
Avoid rapid, jerky or bouncy motions. Jerky and bouncy motions can result in injuries to even warmed up muscles.
AVOID SHARP SUDDEN PAIN
But do take each stretch to a point of mild discomfort and hold it. Mild discomfort indicates you are reaching the edge of the muscle's range. However, sharp pain is your body's way of telling you that you've exceeded that range and you may actually be causing damage.
BREATHE!
You may find yourself holding your breath while stretching. That is not relaxing, so breathe! Once you reach your point of mild discomfort while stretching, exhale. If done properly, you will feel your body relax more and more, allowing your stretches to become deeper.
PERFORM MULTIPLE REPITITIONS
Try three repetitions of each stretch and hold the first rep for 10 seconds, the second rep for 15 seconds, and the last stretch for 20 seconds. Over time, you will find yourself stretching further with increased ease each time. Soon, you will find yourself saying, "Wow! I can touch my toes!" As you become more flexible, do not be afraid to increase your hold times to 25 seconds or beyond.