Fitness Q&A by Richard Weil
I'm frequently asked at least one of these questions and the simple answer is that you ought to stretch whenever you feel you need it (i.e., tight, tension, stressed). The more complicated answer is that there is virtually no evidence to prove that stretching prevents injuries or improves performance, and so it's not really possible to answer the questions with certainty. We all know that stretching feels good, particularly after a tough workout when you want to cool down, but again, there's no evidence to prove that it prevents injuries or improves performance.
With that said, I think it's fair to note that most people who stretch do feel better as a result of it, and most fitness professionals agree that it's important to do at least some stretching. Plus, if you've ever sat at your desk or in your car for several hours you know how tight your back, legs, and neck can get, and then there's nothing like a good stretch to help refresh you.
As for how often and when to stretch, like I said, the simple answer is whenever you feel like it. If you feel tension in your neck or back while sitting at your desk, get up and stretch. If you're at the gym, tune into your body, feel where the tension is, and stretch into it. If your legs feel tight, or you've been in your car for many hours, take some time to stretch out.
I recommend that you try an experiment if you want to know the best combination of stretching and aerobic or resistance exercise. That is, stretch before your workout for one week, then stretch after your workout the following week, and then stretch before and after the final week. Make notes about how it feels, if it improved your performance, and any other observations. With that information, you can determine how your body responds and make adjustments accordingly.
As for how long to hold stretch, you ought to stretch until you feel looser, whether it's 15 seconds, one minute, or more. Remember, you're stretching to loosen muscles and feel better, so forget counting. Instead, tune in to your body and hold the stretch until the muscle feels looser.
There are three main stretching techniques. The first is called static stretching. To use this technique, stretch gently until you feel a mild amount of tension in the muscle (make sure you know what muscle you're stretching), hold it, and then as the muscle relaxes stretch a little further. Breathe slowly as you hold the stretch, don't bounce, and relax all other muscle groups so that you focus on the muscle you're trying to stretch.
An effective technique to enhance static stretching is to do five to 10 minutes of light cardio to get your legs warm, stop to do some static stretching, and then get back to your cardio. You may prefer this to a cold stretch without the light cardio warm-up first.
The second stretching technique is called proprioceptive neuromuscular facilitation (PNF). PNF is where you contract the muscle against resistance (usually another person) so that you create an isometric contraction (tension but no movement). The contraction is held for about five seconds and then released, after which the muscle can stretch a little further.
PNF works by fooling the brain into thinking the muscle is looser than it is. The way it does that is by changing the size of stretch receptors in the muscle that communicate with the brain and tell it whether the muscle is overstretched or not. When muscle length changes (like during an isometric contraction when it shortens), the receptors relax, widen, and send signals to the brain to release tension in the muscle. When that happens muscles can stretch a little further. It works every time and with virtually all muscles.
PNF is an advanced and very effective stretching technique. You can ask one of the trainers in your gym to show you how.
The third type of stretching is ballistic stretching. It is aggressive with repetitive bouncing motions where the muscles and tendons are rapidly stretched. Some of the pro and college teams use this technique in brief, dynamic sessions, close to game time after the athletes have spent time warming up with light jogging or other activities. For the majority of recreational athletes there's no advantage to this type of stretching and there is a risk of muscle or tendon strain, so I don't recommend it.