Delayed-onset muscle soreness usually occurs 24 to 36 hours after a workout. The exact cause of muscle soreness isn't clear. It may be due to the build up of energy waste products in the muscle. It may also be due to microscopic tears in muscle fibers.

If your discomfort is mild, you can continue your exercise program. However, if you have substantial pain with exertion, stop exercising immediately and consult your doctor.

Muscle soreness is most likely to occur after trying a new exercise or activity or with an increase in intensity, frequency or duration of exercise � for example, if you've been running a mile a day and you increase to 3 miles a day.

Also, certain types of strength training � such as those which emphasize lengthening muscles � are more likely to result in muscle soreness. Soreness usually decreases after a couple of weeks of consistent exercise. To reduce this soreness, avoid working the same muscle groups on consecutive days and add low-intensity exercise, such as walking, to your workout.

Treatment of mild muscle soreness may include:

• Icing the affected area
• Using over-the-counter anti-inflammatory drugs, such as ibuprofen or naproxen