At least once a week, I push myself hard in my workout (by increasing weights, doing something new, or upping the resistance or speed on a cardio machine). Predictably, I am sore the day (and sometimes two days) after the hard workout. It is what I consider the "good" kind of sore, when you know you worked hard and there is a lactic-acid buildup in your muscles. I've always wondered, though, how much is too much soreness? Is once a week okay, or is it too much? If it lasts two days, does that mean I've REALLY overdone it?

Your once-a-week "push" is an effective way of making improvements. You seem to have an accurate awareness of muscle ("good") soreness and joint ("bad") soreness. That's important. Pushing yourself to the point of muscle soreness is an inescapable result of working out hard. Pushing yourself to the point of soreness in your joints is not inevitable or necessary and can lead to unnecessary injuries.

Any results-oriented workout program is based on the overload principle. This means that to increase strength, flexibility, or aerobic power you have to push your body to work harder than it typically works. Your body responds and prepares for the next workout by making your muscle fibers stronger, bigger and more resilient. When you think about it, your body is really an amazing work of science. It likes -- welcomes, even -- the exercise challenges you throw at it and is always thinking up ways to meet those challenges.

But, since you asked, let's talk about lactic acid buildup. It is true, you do build up lactic acid with high-intensity exercise. But there are two common kinds of exercise-related muscle soreness. One is acute soreness, the kind that occurs during or immediately after exercise. This is the type of soreness cased by excess lactic acid flooding into your muscles. The discomfort usually subsides after a minute or two of rest. Once the soreness goes away, you can usually continue exercising without any residual effects.

The other type of soreness is known as delayed-onset muscle soreness (DOMS). It develops 12 hours or longer after exercise. DOMS is thought to be a result of microscopic tearing of the muscle fibers. The soreness you feel reaches its peak within two days after the activity and subsides over the next few days. A certain amount of DOMS is a reasonable and expected consequence of getting in shape; but if you are so sore that your legs buckle when you walk down stairs or you can barely lift a pencil, you have overdone it.

If you are prone to soreness (and some of us are more so than others), you might consider massage. This is an effective way of reducing soreness and may allow you to return to the top of your game a bit more quickly.

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