Muscle Cramps

Exercise-associated muscle cramps have a variety of causes, with sodium loss and muscle fatigue topping the list. Since I've already covered muscle cramps from sodium loss in a previous post, I want to cover the muscle fatigue theory.

The muscle fatigue theory states that when a muscle is pushed beyond it's capacity during exercise, it will become over-stimulated, resulting in excessive muscle contraction. A cramp is sustained muscle contraction. I like this theory for a variety of reasons, with the first being that it is easy to train muscles that are fatiguing easily. Second, there are other problems that lead to muscle fatigue that are easily fixed.

Frquently, muscles fatigue when they are working harder than their neightboring muscle groups. Some of the culprits include the Anterior Tibialis in the front outside part of the calf, the calf muscles, gluteus medius and minimus (smaller butt muscles), and the muscles of the hands and feet. If you are getting any cramps and/or pain in these areas, you might be suffering from muscle fatigue.

These are hard working muscle groups. The anterior tibialis has been considered the culprit for shin splints for years. This muscle does double duty during running for both lifting the toes off the ground and slowing down the lower leg so that you can keep up with your legs. This slowing down, or deceleration, puts a lot of strain on the muscle and may be responsible for other problems as well.

The muscles in the hands and feet are small, yet important and are more likely to cramp during swimming.

The small hip muscles of the butt play a role in stabilizing the pelvis and can cramp during almost any sport.

The calf muscles are also likely to cramp when trying to keep up with the bigger muscle groups of the legs: the quads, the hamstrings and the gluteus maximus.

Smaller muscles fatigue not only from poor posture and core strength, but also from intense exercise. One of the most frequent symptoms for latent exercise asthma is also muscle cramps (the smaller muscle groups are the first to pay for decreased oxygen delivery).

Cramps are not just a fluid/electrolyte disorder and may have an underlying problem that, once diagnosed, is easily fixed.

Things Learned from the Philly Bike Race: Part I

For the past 12 years, I have been the race doctor for the Philadelphia Intenational Cycling Classic. The sports medicine that I have learned from watching professional cyclists ride 156 miles is way beyond what I can find in textbooks. Some of the things I have learned have become topics of great interest to me, leading to writing of my books and directing the practice of sports medicine for cyclists at the Performance Lab p/b Rothman Institute.

The next few posts will share some ot the endurance sport specific problems that affect even the most seasoned of athletes.

First, a favorite topic of mine: core strength in endurance athletes.

The medical car follows closely behind the main pack of riders. At the back, I can see who is suffering and why. Although it sometimes has to do with fitness, more often than not, it is easy to tell what else is preventing someone from keeping the pace, especailly going up hills.

The "core" is a group of muscles that stabilize the trunk while the arms and legs are moving. Core weakness is especially noticeable when standing out of the saddle. As I tell most of my patients with overuse injuries, "Overuse injuries occur when the exercise demands exceed core strength or endurance capacity."

The same is true for exercise fatigue. A stable core will allow for more efficient power transfer to the pedals, especially when standing out of the saddle.

The medical car passed a group of riders, all of whom had been dropped. As they stood out of the saddle, their hips were wobbling back and forth. Instead of pushing on the pedals, the pedals were seemingly pushing back at them!

Core fatigue occurs even faster with improper bike fit. Most often, the bike fit isn't matched to the core strength. Although low back pain can occur, it is usually weakness and decreased power that results in poor fit.

First Lesson from Philly: Focus on core strength in the off season and make sure that your bike fit matches your core strength. Bike fit for comfort is one thing, but bike fit for power is another and needs to be adjusted accordingly.