CARING FOR ATHLETES
QUESTION: Why are my muscles sore 24—48 hours after a workout?
SPORTS MEDICINE HOTLINE:
There are two types of muscle soreness. The first is experienced during the workout and is acute. Insufficient blood circulating to the working muscles is usually the cause of pain during a workout. This type soreness goes away soon. The delayed muscle soreness you are experiencing occurs 24-48 hours after a workout and is of more concern.
Until recently, exercise scientists believed muscle soreness was due to one of three major factors. The most popular theory was that accumulation of lactic acid in muscle tissue caused the soreness. Today, however, evidence shows that pain caused by lactic acid occurs only during exercise-not 24-48 hours later. Another theory, the “spasm theory”, was common in the 1960”s. According to this theory a lack of blood supplying the muscles being exercised triggered the release of certain chemicals that stimulated the nerve endings. In turn this stimulation produced muscle spasms and from this came soreness. The third theory, known as the “torn tissue theory”, assumed that tears in the muscle tissues occurred during intense workouts. These tears released myoglobin and other chemical substances, which later produced pain. Recent studies have proven; that these tears are not the major reason for the onset of delayed soreness.
The actual cause of muscle soreness appears to be related to eccentric contractions (the opposite of concentric). This type of lengthening (instead of concentric shortening) contraction produces the greatest amount of tension because the outside force is frequently greater than the force the muscle can generate. The muscle lengthens as it yields to the outside force of weight and gravity. This tremendous tension microscopically tears the connective tissue in and around the muscle, including the ligaments and tendons.
What does this information mean to you? How can you avoid muscle soreness? The answer is relatively simple: to avoid muscle soreness, you must avoid doing too many high-intensity eccentric “negative” repetitions. Eccentric-contraction training does have its place in increasing muscular bulk and strength. Muscle soreness from eccentric contractions is not a major concern unless the soreness affects competition. For this reason, I recommend that this type training be stopped several days prior to competition.