Cramping my style?
Added by Mike Bradley 23 September 2010

What Causes Muscle Cramps
The exact cause of muscle cramps is still unknown, but the theories most commonly cited include:

• Altered neuromuscular control
• Dehydration
• Electrolyte depletion
• Poor conditioning
• Muscle fatigue
• Doing a new activity

Other factors that have been associated with muscle cramps include exercising More...in extreme heat. The belief is that muscle cramps are more common during exercise in the heat because sweat contains fluids as well as electrolyte (salt, potassium, magnesium and calcium). When these nutrients fall to certain levels, the incidence of muscle spasms increases. Because athletes are more likely to get cramps in the preseason, near the end of (or the night after) intense or prolonged exercise, some feel that a lack of conditioning results in cramps.
Research Supports Altered Neuromuscular Control as the Cause of Cramps
While all these theories are being studied, researchers are finding more evidence that the "altered neuromuscular control" hypothesis is the principal pathophysiological mechanism the leads to exercise-associated muscle cramping (EAMC). Altered neuromuscular control is often related to muscle fatigue and results in a disruption of muscle coordination and control.
According to a review of the literature conducted by Martin Schwellnus from the University of Cape Town, the evidence supporting both the "electrolyte depletion" and "dehydration" hypotheses as the cause of muscle cramps is not convincing. He reviewed the available literature supporting these theories and found mostly anecdotal clinical observations and one small case–control study with only 10 subjects. He also found another four clinical prospective cohort studies that clearly did not support the "electrolyte depletion" and "dehydration" hypotheses as the cause of muscle cramps. In his review, Schwellnus concludes that the "electrolyte depletion" and "dehydration" hypotheses do not offer plausible pathophysiological mechanisms with supporting scientific evidence that could adequately explain the clinical presentation and management of exercise-associated muscle cramping.
He goes on to write:
"Scientific evidence for the "altered neuromuscular control" hypothesis is based on evidence from research studies in human models of muscle cramping, epidemiological studies in cramping athletes, and animal experimental data. Whilst it is clear that further evidence to support the "altered neuromuscular control" hypothesis is also required, research data are accumulating that support this as the principal pathophysiological mechanism for the aetiology of exercise-associated muscle cramping (EAMC)."
Carol E. Torgan, Ph.D., FACSM (National Heart, Lung and Blood Institute):
Cramps are miserable. I'm an exercise physiologist who specializes in skeletal muscle, so let me give everyone a little background about cramp causes and prevention.
A cramp is an intense, involuntary contraction of a muscle that usually occurs during or immediately after exercise. Cramps were traditionally thought to stem from fluid or electrolyte imbalances, but they are not always the reason. Cramps may occur following chronic muscle use by individuals, such as musicians, who are not sweating.
 Cramps have also been attributed to extreme environmental conditions or metabolic abnormalities, but again there are examples where this doesn't hold. Cramps typically occur in situations that cause muscle fatigue, such as toward the end of long, strenuous or intense rides.

A current theory suggests muscle cramps result from fatigue that triggers abnormal neural activity. There's an increase in neural input telling the muscle to contract, and a decrease in signals telling the muscle to relax. The result is a vigorous contraction of part or all of the muscle.
The presence of dehydration is thought to accentuate muscle fatigue, adding insult to injury.
Cramps are most common in muscles that span two joints. The hamstrings are a great example. Other two-joint muscles include part of the quadriceps (thigh muscle) and the gastrocnemius (calf muscle). 
The pain is brought on by an intense, active contraction of the muscle cells themselves. Although cramps may occasionally be the result of 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.
 Here’s a checklist for every cramp-afflicted person to think about.

• People most prone to cramps are older, have a family history of cramping and have poor stretching habits.
   
• Do you get cramps in muscles that are not working very hard during cycling (such as the biceps)? If you do, this suggests a systemic factor is the main culprit (e.g., an electrolyte imbalance or dehydration). However, if cramps only occur in the muscles doing all the work, then fatigue is probably to blame.
• Do cramps occur only in hot conditions, or do you get them if you ride hard on mild days? Review your training diary and look for patterns. Check weather conditions, type/length of ride, eating/drinking patterns the day before, during and after the ride, location(s) of the cramps, etc.  For example, if your cramps always occur in the same muscle when you ride a certain bike in a certain position (i.e. aero), then you can pinpoint it to local muscle fatigue and train accordingly.
  

Preventing Muscle Cramps
Until we learn the exact cause of muscle cramps, it will be difficult to say with any confidence how to prevent them. However, these tips are most recommended by experts and athletes alike:
There are 4 issues to be considered in the prevention of muscle cramps:

• Training - as with the two other forms of activity related muscle pain, training to the level of the anticipated activity will decrease the possibility of cramps. (Improve fitness and avoid muscle fatigue):

• Strengthen the muscles. Muscles that are not worked hard are unlikely to cramp. Carry out a long term strengthening programme which should also include plyometric type exercises.Stretch muscles thoroughly on a daily basis.
• Stretch regularly after exercise
• Train consistently. Your body will build up a resistance to muscle cramps if it is used to the exercises that it is doing. It’s when you push too hard or try something that you haven’t trained on that leads to muscle cramps;
• Another cause of muscle cramps can be the build up of lactic acid in the muscles. If you’re pushing yourself too hard during a workout, your body isn’t able to burn off all of the lactate that it is producing and lactic acid forms, causing that burning sensation in your legs. And that sensation can sometimes lead to a feeling of muscle cramps after a workout.

• Hydration - dehydration is believed to be the second most common cause of muscle cramps after exerting beyond your training.

• Ensure you take on enough carbohydrate prior to training or competition. Have a high carbohydrate meal 2-3 hours before training or competition. If you take part in long endurance events then make sure you take on board enough carbohydrate during the event. A drink may not be enough - you may need to eat as well!
• Keep hydrated. Drink regularly throughout the day prior to training and competition. Make sure you drink enough during the event itself.
• When the muscle is dehydrated, it will cramp from having too many electrolytes in it; while the muscle that has too much water in it will also cramp because of the lack of electrolytes. Muscle cramps are some of the warning signs for dehydration as well as for hyponatremia (too little salt/electrolytes).

• Electrolyte replacement - sweat contains approximately 2 grams sodium/liter, 1 gram chloride/liter,0.2 gram potssium /liter, and 0.1 gram magnesium/liter - and if you are acclimated, these concentrations are even lower. Except in extreme circumstances, dietary intake will replace these losses, but if you are going to be exercising in excessively hot or humid conditions, most trainers would suggest paying close attention to salt intake and even adding 1/2 tsp of salt (1150 mg of sodium) per day to your food. Don't worry about elevating your blood pressure as we are talking about a short term supplement and the sodium effect on blood pressure happens over months to years. A sports drink might help, but it is likely that maintaining adequate hydration is more important than the small amount of electrolytes they contain - and water is still a lot less expensive. The role of other micronutients and vitamins are completely unproven.

So what's the answer?

Most muscle cramps are not serious. If your muscle cramps are severe, frequent, constant or of concern, see your doctor.
Everyone's physiology is different, and thus the answer to preventing cramps almost certainly varies from person to person as well. Maintaining adequate fluid replacement and nutrition is essential for optimal physical performance above and beyond the benefits in preventing muscle cramps. From there it becomes a trial and error approach to see what might help you. If you suffer from muscle cramps, try manipulating supplements - potassium, magnesium, calcium.
If cramps do occur, gently stretching the affected muscle will give relief, and some authorities feel that stretching used prophyllactically will prevent cramps. Calf cramps 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.
Recommendations for those suffering from frequent muscle cramps?

• #1 is an adequate training program designed for the event being considered
• a close second is maintaining good hydration
• a sports drink containing electrolytes for severe conditions of heat and humidity
• a regular program of stetching before, during, and after exercise.
• Pushing beyond your training is a sure fire way to get them. Remember to " train to the ride" i.e. push yourself to the level of your competitive ride once a week.
• Warm up before exercise

• Stretch the calf muscle: In a standing lunge with both feet pointed forward, straighten the rear leg.
• Stretch the hamstring muscle: Sit with one leg folded in and the other straight out, foot upright and toes and ankle relaxed. Lean forward slightly, touch foot of straightened leg. (Repeat with opposite leg.)
• Stretch the quadriceps muscle: While standing, hold top of foot with opposite hand and gently pull heel toward buttocks. (Repeat with opposite leg.)