Stretching improves flexibility, which is a key part of fitness - it helps you move better and relieves muscle stiffness. You should stretch after a warm-up and/or when cooling down after a workout, since it is easier and safer to stretch a warm muscle than a cold one.

The safest type of stretching is called "static" stretching, in which you stretch through a muscle's full range of movement until you feel resistance, and then hold that position for 10 - 30 seconds, relax, and repeat the stretch several times. Another type of stretching is "ballistic" stretching, in which you do bouncing, repetitive movements while stretching; this is not recommended for most people. Some athletic trainers recommend "active-isolated" stretching, in which one muscle is isolated and stretched by contracting the opposite muscle.

Too-vigorous stretching, stretching until it hurts, or holding the stretch too long are not recommended - you can injure yourself. Stretching should feel good. You should stretch to the point of mild discomfort, at most, and then ease up.

Although there is no hard evidence that stretching prevents injury, many athletes believe it does. Nor will it prevent muscle soreness if you've overdone your exercising. But it does promote flexibility, and it feels good. Many also advocate it as a stress reducer and relaxation technique.

Next week we'll look at some tips for stretching.

Related information Lifestyle changes - Exercise

Source: UC Berkeley Wellness Letter. Foundations of Wellness - Fitness.