Have you ever pushed yourself so hard, and so intensely at some kind of physical activity (be it biking, sprinting, lifting, whatever) that your muscles suddenly feel like they are burning, and eventually the pain becomes almost unbearable and your muscles quickly give out?
If you are a gym rat, you’ll no doubt experience this pain on a frequent basis. Some people refer to this as ‘the burn’, and actively aim for it, while for others it’s just a rather unfortunate (albeit, strangely pleasant once it subsides) side effect from lift
What I’m talking about is lactic acid build up in the muscles.
When you are doing any kind of physical activity, inside your muscles there are chemical reactions taking place. Oxygen is converted into carbon dioxide, and the blood is pumping through them trying to shift it, and glycogen is being burned.
If a person was to train at a very steady pace (weights so light a child could lift them, etc.) then the chances of having a lactic acid attack are very remote, unless the session went on for hours and hours and hours, which is unlikely. This is because a person who trains very light and steady is training aerobically (with oxygen.) This means there is always an abundance of oxygen available to replace the carbon dioxide in the muscles.
As bodybuilders, we work out in an anaerobic manner. That means, without oxygen (or very little oxygen.) It therefore follows that, because we take in very little oxygen whilst working out, our carbon dioxide levels build and build, until we are quickly overwhelmed – and one such side effect of a lack of oxygen in the muscles is lactic acid.
It’s commonly thought that our muscles fail because of lactic acid, which is untrue. In fact, the lactic acid acts as a kind of anaesthetic which prolongs our efforts somewhat.
While you may feel the burn of lactic acid during training, you’ll notice it quickly subsides and you feel good. But, you’ll also likely notice that within the next few days you could be left with a very severe pain – sometimes incredibly painful – which can make your muscles feel stiff and feel like they have cramp.
You can minimize lactic acid build up by doing some stretching between sets and after your workout, and doing several warm down sets of extremely light weight – which helps to get the blood flowing in and out of the muscle again, getting rid of the lactic acid deposits. Also important is keeping hydrated before, during, and after training.