When is too much too much?
I think most are aware of the soft, fleshy, central part of a muscle, the jellylike mass called the belly of muscle compartments. Towards the ends of the muscle, the contractile cells disappear, but their investment of connective tissue continues in order to attach the muscles to the bones.
Have you ever slowed down enough to check out the steak you are getting ready to grill? Compartments are groupings of muscles, nerves, and blood vessels in your arms and legs. Covering these tissues is a tough membrane called a fascia. The role of the fascia is to keep the tissues in place, and, therefore, the fascia does not stretch or expand easily.
What many are not aware, is pain and swelling of chronic compartment syndrome is caused by exercise. Athletes who participate in activities with repetitive motions, such as xc skiing, running, biking, or swimming, are more likely to develop chronic compartment syndrome. This is usually relieved by discontinuing the exercise, and is usually not dangerous. It's hard to get people to stop once they get hooked on the exercise, even if they have pain or not. Many just think they are getting stronger. After all more is better? Not always!
What you might not know is, nor the bike fitter who just uses a plumb line, teaches a heel down style, if muscle were a relatively simple mechanism like a spring, and some investigators have modeled it that way (KOPS) a direct relationship would exist between the tension it could develop at different lengths and the amount of work it could accomplish.
Now comes a something shocking. We are are very different, given that strains result from motion that exceeds "YOUR" limits of both joint & muscles, you have many of both. For example, each pedal stroke causes the femur to seat itself more closely into the menisci. A too low saddle causes more stress. This happens because the foot, at the ankle has less movement due to the cleat, so the lower leg rotates less than the upper leg that rotates inward at knee and hip. Many think you should not any rotation? I guess they don't know that muscles run on an angle that allows you to rotate about an axis? We don't know what A&P class they took, perhaps they missed that week? We know that a heel down pedal style causes even more compression to the joint and also to the muscle, down into the tendons.
Does "compression, shearing, tension" ring a bell? Too much of any of them will cost you!
Perhaps you have heard of Q-angle, its the deviation between the line of pull of the quadriceps femoris and the patellar ligament. A Q-angle of 10-degress is considered normal, but look around and note how many different shapes you see (wide pelvis, knock knees, etc...), but what about the unseen (flat lateral femoral condyle, meniscus injury) susceptible to overuse injury.
I recall a good friend from Norway at school on a full 4 year ride for xc skiing for the University of Utah Ski team. He was Norway's National XC Champion, a big deal! Yes he had a full 4 year ride to school, but they dropped him, he lost his schooling and was sent back to Norway. What happened?
His styles of running, skiing, cycling was leading towards too much compartmental pressure to his lower legs, along with vascular compromise due to a too "heel down" style. It is well known to use the whole foot as the base to skate from, but perhaps for that sport. He was super fast, he had the cross-section of muscle, he had a very fast pace, but his style took him out. Next!!! That's how it works, if you are out of the game, you are out and in his case back to Norway. He became very sick and who knows what damage he has many years later.
Compartment syndrome is the compression of nerves, blood vessels, and muscle inside a closed space (compartment) within the body. This leads to tissue death from lack of oxygenation; the blood vessels being compressed by the raised pressure within the compartment. Compartment syndrome most often involves the forearm and lower leg. It can be divided into acute, subacute, and chronic compartment syndrome.
The team would ride their mtb bikes for preseason training, and this guy even used his mtb bike and oh yes, would ride too heel down because he learned to use more leg flexion. It didn't help him that the xc team would run up steep hills behind the shcool and I mean full speed ahead and he was always the king of the hill.
This was somewhat a epidemic with the team. The reason, strenuous exercise and they wanted to be top dog in NCAA and that means you push beyond the limits and they did often.
This is important to know, as you get ready for the 2011. High tissue pressure impedes blood flow and causes muscle ischemia during repetitive exercise. That means you need to get it right the first time.
Compartment syndrome can be either acute or chronic.
Acute compartment syndrome is a medical emergency. It is usually caused by a severe injury. Without treatment, it can lead to permanent muscle damage.
Chronic compartment syndrome, also known as exertional compartment syndrome, is usually not a medical emergency. It is most often caused by athletic exertion as in the case of one of the fastest xc ski racers in the world.
Actually, muscle consist of three interdependent elements: 1) contractile component, 2) a series elastic component, and 3) a parallel elastic component.
- contractile component - actively develops tension and shortening, can lie in part in the tendinous filaments into which muscle fibers insert, its function to tension development in the whole muscle-tendon unit when the muscles shortens from a previously stretched position.
- parallel elastic component - comes into action only when the muscle is stretched, its mostly connective tissue and is responsible for the resting tension. The physical arrangement has practical consequences. During standing or at low-speed locomotion, the contractile component is responsible for the mechanical work and power output. But at higher speed, shortening contractions (positive work) are immediately preceded by a lengthening contraction (negative work) which the active muscles are stretched and mechanical energy is stored in the muscle's elastic and viscoelastic components.
This energy is then released during the shortening contraction that immediately follows and results in
"enhanced work and power output." The "stretch-shorten" cycle in skeletal muscle is seen in moderate and high-speed movements results in a very efficient use of muscle resources and enhanced work output.
It's these extensions of the cordlike tendon, being braided with one another, so that tension in any part of a muscle is usually distributed more or less equally to all parts of the attachment to the bone.
Because a tendon collects and transmits forces from many different muscle fibers onto a very small area of bone, the site of the tendinous attachment is normally marked by a rough tubercle on the bone.
The structure of the insertion of the tendon onto the bone and the tendon's behavior under mechanical loading is very similar to that of a ligament (the structure that holds bones together).
The size and shape of a tendon and the speed of loading on it are the two main factors that determine its strength. The tendon is very important link between muscle and bone, the stress on it increasing as its muscle contracts.
Large muscles usually have large tendons. During normal activity a tendon usually experiences only 25% of the maximal stress it can withstand; very rapid, unexpected stretches of a tendon are common conditions for tendon rupture.
For example, having your heel unexpectedly drop into a hole in the ground could cause rupture of the Achilles tendon.
Note: The fact that the relative amounts of connective and contractile tissue vary greatly from muscle to muscle has at times been disregarded and has led to great discrepancies when experimental physiologist have reported the physical properties of muscle.
The tetanic force, the rate of chemical energy disipation, or both proportionate to the number of interactions between the cross bridges and the actin filaments.
If the muscle goes into a state of rigor, forcibl attempts to stretch it will result in a tearing of the filaments, usually in the I bands.
Compartment syndrome develops when swelling or bleeding occurs within a compartment. Because the fascia "does not stretch," this can cause increased pressure on the capillaries, nerves, and muscles in the compartment. Blood flow to muscle and nerve cells is disrupted. Without a steady supply of oxygen and nutrients, nerve and muscle cells can be damaged.
In acute compartment syndrome, unless the pressure is relieved quickly, permanent disability and tissue death may result. This does not usually happen in chronic (exertional) compartment syndrome.
Compartment syndrome most often occurs in the anterior (front) compartment of the lower leg (calf). It can also occur in other compartments in the leg, as well as in the arms, hands, feet, and buttocks and between your legs while on a saddle.
Chronic (Exertional) Compartment Syndrome
The pain and swelling of chronic compartment syndrome is caused by exercise. Athletes who participate in activities with repetitive motions, such as running, biking, or swimming, are more likely to develop chronic compartment syndrome. This is usually relieved by discontinuing the exercise, and is usually not dangerous.
What to do if you over did it?
Nonsurgical treatment. Physical therapy, orthotics (inserts for shoes), and anti-inflammatory medicines are sometimes suggested. They have had questionable results for relieving symptoms.
Your symptoms may subside if you avoid the activity that caused the condition. Cross-training with low-impact activities may be an option. Some athletes have symptoms that are worse on certain surfaces (concrete vs. running track, or artficial turf vs. grass, trails, etc...). Symptoms may be relieved by switching surfaces.
No comments:
Post a Comment