Flexibility is perhaps one of the most neglected areas of one's fitness regime. Sure, many people do it. Budo training places greater emphasis on it than most other activities. However, even amongst those that do include stretching in their routine, for many it is nothing more than a warm-up; and maybe a cool-down.
Stretching is, in itself, a great way to stay in shape. Yes, it is a good way to warm up and reduce the risk of injury. Yes, it is also a great way to unwind after a gruelling workout. But it is so much more than these, though.
A flexible body is a relaxed body. Reflexes are quickest when the body is relaxed. In a combat situation, shaving off the extra millisecond from our reaction time could mean the difference between an effective defence and counter, and a futile effort.
Flexibility also optimises the muscles' range(s) of motion. That helps in executing more complex techniques that require the body to move beyond its normal range of standing, walking, sitting, and maybe running. For example, people with flexible leg muscles can kick higher.
The increased agility in the body that results from regular stretching also enables the muscles to take much greater loads and perform better than they would otherwise. Agility leads to higher jumps, longer leaps, faster strength gain, and so on.
With age, the human body becomes more stiff. Stiffness leads to a limited range of movement, unwanted aches and pains, and many other physical discomforts. Supple and agile muscles keep the body young in the truest sense of the word.
Regular stretching prevents stiffness and soreness. That is why a good stretch after a hard training session prevents, or at least reduces, the fatigue muscles and joints experience the following day.
Approached the wrong way, even stretching can cause injuries. Even as a warm-up, stretching cold muscles is not a good idea. It can cause strains and tears. It is best to stretch when the body is slightly warmed. So before a warm-up stretch, a bit of light jogging on the spot, or a few (slow and controlled) jumping jacks will raise your body's temperature enough to reap the greatest benefit from your warm-up.
On the other hand: done the right way, stretching benefits the body immensely; certainly far more than most people give it credit for. The secret lies in how it's done. The greatest gain in flexibility is achieved when the body is warm.
A post-workout stretch routine is best. At this time, the body is heated up and the muscle fibres are most receptive to being stretched. While the stretches increase flexibility, they also provide a great low-impact cool-down for the body after a high-impact training session. A pre-workout warm-up routine (done properly) can also be an excellent route to flexibility while gradually preparing the muscles for the heavier loads to come.
Stretching really fine tunes the body physically and helps the mind relax, too, by way of the controlled but continuous breathing during each stretch. Altogether, it is a perfect supplement to martial arts training. Even on non-training days, fitting 10 to 15 minutes of stretching into the day will help tremendously.
It is a great way to start the day, preparing the body and the mind for the day ahead. It is also a great way to unwind at the end of a tiring day.