When fitness experts talk about ?doing a warm up?, they generally mean doing some kind of general activity that gradually raises the heart rate. They will happily tell us that doing so reduces the risk of injury during the following workout ? but don't often explain exactly how. In fact, a good warm-up should involve more than just this ?general activity?. The second, less commonly described aspect is the ?dynamic stretching? we mentioned in last week's article. And there are many more reasons to warm up than simple injury risk reduction

WHY WARM UP?

When you start moving in any way that raises your heart rate, certain changes start to take place in your body. Your respiratory rate increases. Bloodflow throughout your body increases, which means that the levels of oxygen and nutrients that are delivered to your cells also increase. In effect, all your body's systems are warned you're going to be making demands on them, and primed to meet those demands.

Once you're at this point, you're ready to move onto dynamic stretching. This, you'll remember, involves slowly performing the same kinds of movements you'll be making in your workout, and gradually increasing the speed. As specific muscles, tendons and joints follow the movement patterns they'll be expected to complete later, they become used to the movement, and less likely to tear when the movements are made at higher speeds. This stage also works as a cue for your nervous system to ?switch on? the specific neuro-muscular connections it will need for those movement patterns.

Lastly, this two-stage warm-up helps you to prepare you mentally for the coming workout. Regardless of what that workout might be, you'll do it better, and enjoy it more, if you're able to bring your full focus into it. By taking the time to warm up before you start exercising ?for real?, you're giving yourself the mental space to switch your focus to where you need it to be.

HOW SHOULD I WARM UP?

The general part of the warm-up can be done in any way that gets your heart beating faster. If you have a piece of cardio equipment available? a bicycle, rowing machine, or stepper ? feel free to use it; or simply walk and then jog. Whatever you use, start very gently, and gradually increase the intensity until you can feel your body getting warm and your heart rate starting to rise. The specific intensity will depend on your current fitness level ? but it should have you working at a level where you're energised, not exhausted.

Some people continue until they feel a light sweat, but because this can be more reflective of humidity than body temperature (and because some people sweat more easily than others), it may not be the most useful measure. Experts suggest 3-5 minutes, but if your exercise environment is particularly cold, it may need to be longer.

Once you're feeling warm, it's time to bring in the dynamic stretching. What you do here will depend totally on what kind of exercise you're planning. For a martial art, it might involve light sparring at ? speed, or simply performing some of the techniques in slow motion. For a sport, it could involve mimicking the same kinds of movements you'll be using on the field or court, in a slow, controlled way. There are no specific time guidelines for how long this should take ? but allow enough time for repeating each movement, starting slowly and gradually increasing the speed until you're working at the level you expect during your workout

Finally, once you're warm, stay warm. Especially if the workout that follows will be particularly vigorous, don't stop to do a static stretching routine. This will give your body a chance to cool down again, and undo much of the good you've done by warming it up in the first place. If you have any questions about either kind of warm up mentioned in this article, please don't hesitate to e-mail me on tanja@optimumlife.co.nz. Otherwise, may every day bring you closer to your Optimum Life.