• soreness during or immediately after exercise
• delayed onset muscle pain
• muscle cramps (which can occur during or post exercise)

Exercise requiring significant effort, either high energy demands (low resistance, rapid contraction rate) or substantial muscle effort (high resistance, low contraction rate) is often associated with muscle pain or discomfort. No study has identified a single cause for this discomfort, although the fact that it occurs more quickly in a muscles with a limited blood supply suggests that the culprit is a byproduct of muscle metabolism. In addition, as the ingestion of sodium bicarbonate will delay the onset of pain, it is thought that the metabolite is acidic in character.

Lactic acid is the likeliest candidate although other metabolites such as pyruvic acid and ammonia have also been mentioned. Based on the differing findings in various studies in the literature, it is more likely that pain in the actively contracting muscle is multifactorial related to a combination of acidic intermediate metabolites, ionic shifts at the cell membrane level (K, magnesium), and actual changes in the muscle cell proteins themselves. As training will increase the level of activity at which discomfort occurs indicates that the muscle cell can adapt to these factors.

It is interesting to note that the body has a mechanism to deal with this discomfort. Endorphins, opiate like substances produced internally, are secreted into the central nervous system during endurance exercise and alter the perception of pain during prolonged high intensity exercise. Thus we have a mechanism to warn of muscle overuse (pain) as well as an intrinsic process to help us deal with that pain if we opt to continue.

Although the conventional wisdom is that taking aspirin before a ride will cut down on muscle pain during exercise, a study at the University of Georgia recently concluded that even at large doses (20 mg per kg - or 4 standard aspirin for the average rider), aspirin did not delay the onset of muscle pain during exercise or reduce the perceived intensity at which it occurred.

DELAYED ONSET MUSCLE SORENESS (DOMS)

Delayed soreness (or stiffness) begins 24 to 48 hours after exercise and peaks at 48 to 72 hours. It is most evident after "eccentric" muscle activity (actively resisting lengthening of the muscle such as occurs in raising or lowering a weight) which indicates it is due to high tension on muscle fibers and connective tissues and is less common in isometric or static tension activity. The soreness is accompanied by a decrease in muscle strength, a reduced range of motion, and leakage of muscle cell proteins (creatine kinase, myoglobin) into the blood where these enzyme and protein levels can be measured. These three findings indicate that actual muscle damage is the culprit (most likely minute tears) rather than a buildup of metabolic byproducts during exercise. Muscle biopsies confirm that it indeed associated with muscle fiber damage with an inflammatory response.

Generally DOMS occurs after above normal eccentric exercise. It does not appear that soreness from previous exercise increases the chance of further muscle damage. In fact the adaptive process of healing, even from microscopic injury with minimal pain, appears to have a protective effect against the development of additional muscle damage and soreness from subsequent exercise. Theoretically small doses of damage over time will provide cumulative protection - thus the rationale for a gradually progressive exercise training program.

In 1997, a small group of elite athletes with a combination of chronic fatigue and delayed onset muscle soreness were studied. Muscle biopsies were abnormal and the authors speculated that cumulative, low level, chronic injury might interfere with performance. Whether chronic injury is involved in the symptoms we call overtraining is still considered speculative. But it does lend support to the idea that adequate rest in a training program is as important as the actual physical training itself.

MUSCLE CRAMPS (CRAMPING)

It's not unusual to hear the following story:

"I entered my first mountain bike race (18 miles) and at mile 14, my thighs and right calf cramped up. This has happened before on long rides. I thought I trained enough, hydrated enough, and ate enough bananas, but I still cramped up and had to go real slow for the last 4 miles. It was sooooo frustrating. I have another race coming up next month but its only 12 miles but has steeper hills. What should I do? Do tights help reduce cramps? When I get them (cramps) should I massage the cramped area? Should I train the amount of miles of the race?"

A cramp is an intense, active contraction of the muscle. Cramps are much more common when you use your muscles beyond their accustomed limit either for a longer than normal duration or at a higher than normal level of activity. This explains why cramps are more common at the end of a long or particularly strenuous ride or after a particularly vigorous sprint. Cramps are among the most frequent complaint in marathon participants (18% in one study). In another study of cyclists competing in a 100 mile race, 70% of male participants experienced cramps (women, interestingly, had a rate less than half as frequent at 30%). Cramps can occur during activity, in the hours afterwards, or the night after a particularly long ride or competitive event. They become more common with age.

Although cramps may occasionally be exacerbated by a fluid and electrolyte (sodium) imbalance from sweating, that is not universally the case as individuals involved in activities requiring chronic use of a muscle without sweating (musicians for example) will also experience cramps. In one study of marathon runners, there were no differences in sodium or hydration levels between the 15 participants who developed cramps and the 67 who didn't. This was confirmed in another study in ultradistance runners. And although a low magnesium level can cause severe muscle cramping, another study of magnesium supplements in triathletes failed to show any benefits in preventing cramping.

As is often the case when there is no consensus on etiology, you will find many conflicting opinions on treatment options. A review of the literature indicates that it cramps are more likely in the setting of the triad of salt loss, fluid loss and muscle fatigue. The following comments provide some thoughts as to treatment options to consider if you are suffering from frequent muscle cramps:

• training - Exercising beyond your usual level of training (as you push yourself to improve - intervals, long rides) increases the odds of muscle cramping. Thus muscle cramps are to some degree an expected side effect of heavy training. Just as with the two other forms of activity related muscle pain referred to above, increasing your training to better approximate the level of exertion to match the anticipated activity or event will decrease the possibility of incapacitating cramps during the event itself.

• hydration - Dehydration can aggravate muscle cramping, so pay close attention to maintain adequate hydration - both during training and when competing.

• electrolyte replacement - Electrolyte imbalance (as well as magnesium deficiency) is unproven (in physiologic experiments) as a reproducible cause of muscle cramping. None the less, there is significant anecdotal experience that indicates that salt loss (especially in heavy sweaters) is a culprit in muscle cramps in hot conditions. That said, it seems to me it does no harm to make sure you maintain hydration (and to a reasonable degree) electrolyte replacement while exercising.

  Sweat contains approximately 2 grams of sodium/liter, 1 gram chloride/liter, 0.2 gram potassium /liter, and 0.1 gram magnesium/liter (and if you are acclimated to the level of exertion and environmental conditions, these concentrations are even lower). Except in extreme circumstances, dietary intake easily replaces these losses.

  If you will be exercising in excessively hot or humid conditions, most trainers will stress paying close attention to salt intake - and perhaps adding 1/2 tsp of salt (1150 mg of sodium) per day to your food (heavy slating of your meal is probably just as effective). Don't worry about elevating your blood pressure as we are talking about a short term supplement while the sodium effect on blood pressure happens over months to years. A sports drink, with its electrolyte content) will help but it is more likely that maintaining adequate hydration is their most important benefit rather than the small amount of electrolytes they contain. And plain water is still a lot less expensive to keep up the hydration level. But remember that with water "more is not necessarily better" and hyponatremia is always a small risk if you aren't paying close attention to the balance of your intake and losses. The role of other micronutrients and vitamins in preventing cramps is generally unproven - and anecdotal experience with the benefits of home remedies (except for pickle juice - one study and this was via a neural reflex mechanism, not an effect on body fluid composition) is unproven.

  • "I read about a study of cramping during the Hotter'n Hell Hundred in Texas. They took blood samples of riders that cramped and riders that didn't. The most common deficiency wasn't calcium or potassium like many would guess, but magnesium. They suggested using Rolaids as Rolaids have both calcium and magnesium, whereas Tums only contains calcium. I like the fact that Rolaids covers you both ways."
  • "I have been plagued with leg cramps until a friend suggested standard calcium with magnesium supplements. I would take them prior to bed with a large glass of water. Amazingly, no more cramps. I also suffered during long rides and was concerned during a cross-country tour with my wife last summer. I would take one tablet in the morning and afternoon and of course stay hydrated. Not once during even the most arduous days or while sleeping did I suffer any cramps."

  As magnesium is lost in sweat, the idea of a magnesium deficiency is physiologically more attractive than speculation that calcium (unproven as a culprit, probably as you have so much calcium available in your bones to draw upon) is at fault. I could find only a single study in the literature that suggested that relative magnesium deficiency may play a role.

• muscle glycogen stores - replenishment of ATP is necessary for proper muscle cell functioning, thus adequate Caloric intake is necessary for optimal physical performance. Whether inadequate glycogen reserves are also a reason for muscle cramping is speculative.

If cramps do occur, gently stretching the affected muscle will give relief, and preventive stretching can prevent cramps. Calf cramps while riding can be relieved by standing on the bike and dropping your heel, while anterior thigh cramps can be stretched out by unclipping and moving your thigh backwards towards your buttocks. Although a number of medications have been suggested as treatments for muscle cramps (vitamin E, verapamil, and nifedipine to name a few) only quinine has been shown to be effective in scientifically controlled studies. But its high incidence of side effects limits its usefulness as a routine treatment. So what would I recommend for those suffering from frequent muscle cramps?

• Most importantly an adequate training program designed in both intensity and duration for the event or riding being considered
• A close second, maintaining good hydration. Weigh yourself before and after training rides, and if your weight drops, your fluid intake needs to be increased.
• Use a sports drink (containing electrolytes) for severe conditions of heat and humidity. If you are using an electrolyte free replacement, use a reasonable amount of salt in your diet to minimize the small risk of hyponatremia.
• A regular program of stretching before, during, and after exercise.
• Magnesium replacement may have some benefit, but that is speculative.
• Consider a trial of pickle juice in those suffering from debilitating cramps.

The first 2 readers' questions below highlight the role training can play in the prevention of cramps - even though it relates to the question of cramps in a non cycling event. (The answer was provided by an associate at my clinic.)

Q: I started cycling about 6 months ago and trained really hard this summer for a double century. In all the training and the race itself I rarely suffer from any muscle spasms. However since I started cycling I (may just be coincidence) get EXTREME spasms when I hike down hill. Hiking uphill doesn't bother me, but my quads and calves literally freeze up after only 5-10 minutes of down hill hiking. It becomes so painful I can barely bend my leg. Last time I only hiked 1/2 mile and I thought they were going to have to carry me out. I've tried stretching before and it doesn't help. Within hours the spasms are nearly gone and by morning I feel fine. This probably sounds crazy, but I can't figure out how I can bike 200 miles and can't hike 1/2 mile.

A: Here's the somewhat technical answer: The ankle plantar flexors and quads act concentrically in cycling - that is they generate tension (fire) while shortening. Through the down stroke the ankle plantar flexes and the knee extends under the influence of the gastrocs, soleus and quads. At the bottom of the stroke and through the up stroke, the hamstrings are shortening too.

In walking down hill the opposite is true. Your friend is repeatedly letting himself down hill under the eccentric firing of the quads, plantar flexors and hamstrings. To keep from falling forward the hamstrings fire to keep the pelvis from rotating forwards. During stance phase the ankle dorsiflexes over the planted foot lengthening the plantar flexors and the knee flexes lengthening the quadriceps muscles. A pack will change the equation in that it will greatly amplify the intramuscular tension and therefore the work performed by the muscle. Work that these muscles are not trained (training meaning the physiologic and anatomic adaptations to repeated work) to do.

And the short version: In terms of improving the situation the answer is really cross training - his muscles are well equipped for steady state aerobic concentric work at 90 to 110 rpm but not the greater intensity, near anaerobic threshold eccentric work of hiking down hill. I would bet that eight weeks of running including 20% speed/interval work will turn the problem around.

Q: I am 42 years old and I have been cycling for 19 years. I have one real problem that I can't seem to shake. CRAMPING. I have trained longer, harder, faster, further and taken every conceivable >concoction used, special supplements and the thing I have found that works the best although it does not work 100% is drinking Indian tonic water for the week leading up to the race. Am I right in saying that I am just one of those people prone to cramping or can I really do something about it. I must add that I have developed a strange ability to endure these cramps and ride through them only for them to reappear and literally bite me so hard I have nearly fallen off my bike. Kind regards. James.

A: Muscle cramps are probably multifactorial in origin - exercise beyond your limits (distance ridden or maximum levels of exertion), dehydration, electrolyte imbalance, etc. And age is a factor as well. I never cramped until I got into my 40s, and leg cramps are a common complaint of older patients of mine. Once you have corrected all the variables which you can control (except age of course) it then becomes a matter of learning your triggers and riding within your limits (usually defined by trial and error) and understanding that these triggers may vary depending on how well you are trained at the time.

Q: I recently got back on my bike about 6 months ago about the same time I started a low calorie diet. Thus, far I’ve lost about 55 lbs or about 2 lbs per week. I eat a lot of protein (fish, steak, fruits, etc.) except for lunch (salads mostly) and not too much carbs. I consume about 1800 calories per day and burn about 800 per day exercising that mostly consist of bike riding and when the weather does not permit the ride, I’ll hop on the (moderate walking) treadmill for about 30-35 min each time. On the weekends, I’ll ride 20 miles (AM) and another 10 miles (PM) sometimes. This was my regular routine for about 5 months. I am usually riding about the same distance (except for the weekends) and intensity. The past month after a 40 mile ride, I noticed that I am experiencing muscle fatigue and soreness on my entire leg. My legs feel like jelly. The soreness comes almost immediately after the ride after a short rest on the couch. I also notice that I use to ride on the highest gear and now that’s getting too difficult for me and I now have to reduce to lower gears. It just seems that after 6 months of riding my leg muscles should improve, so why am I experiencing muscle fatigue and soreness? - EL

A: A few thoughts on your question.

• My guess is that the muscle weakness is a side effect of what is basically a South Beach diet (high protein, low carbohydrate) with total Calories eaten being less than those expended (which is why you are losing weight). With this scenario, you never really replete muscle glycogen and thus the muscle cells are working on fat metabolism resulting in feeling as if you "have bonked" early on in your rides.

• The soreness is a interesting question. The original theory on next-day muscle soreness is caused by a buildup of lactic acid in muscles, but now we know that lactic acid has little to do it. Next-day muscle soreness is generally attributed to physical damage to the muscle fibers themselves. Muscle biopsies taken on the day after hard exercise reveal bleeding and disruption of the z-band filaments which hold the muscle fibers together as they slide over each other during a contraction.

  Cooling down speeds up the removal of lactic acid from muscles, but as a buildup of lactic acid does not cause delayed muscle soreness, cooling down will not help to prevent this physical injury and muscle soreness. Stretching does not prevent soreness either - although pre ride stretching may help to prevent the physical micro-tears.

  Performing certain exercises beyond your training will almost guarantee delayed soreness: running, hiking or skiing downhill, for example, and lowering weights - what weight lifters refer to as "negatives." In these downhill or downward motions, called eccentric muscle actions, the muscle fibers have to lengthen and then contract, and it's that lengthening-contraction that puts the most strain on the fiber and does the most damage. Cycling is NOT one of the exercises frequently associated with muscle injury and soreness.

  So the question - why your soreness? As it started with your low carbohydrate diet (and weight loss) - and there was no increase in exercise intensity or duration - the low carbohydrate diet is at the top of my list of potential culprits. Other possibilities would be associated dietary deficiencies, such as magnesium, associated with your high protein diet - magnesium deficiency can cause increased muscle cramps for example. As muscles require energy in the form of ATP to work effectively, it is possible that low energy levels are leading to muscle weakness and as a result a greater tendency to actual physical damage to the muscle fibers.

  What would I suggest? For 1 week, eat as many Calories as you use - and make sure 50% of them are from carbohydrate. If you improve, then you have the answer. (a followup email confirmed that a change in diet had helped).