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The muscular engine can use multiple fuels.

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The muscular engine can use multiple fuels.

To improve the functioning of your muscles,
choose well your diet!

During exercise, muscle burns sugar as well as fat and sometimes proteins.

Sugar consumed by motor muscle is glucose. Glucose links are grouped into huge chains called glycogen. This large structure is the sugar storage form in the liver and especially in muscle.

Fat burned in muscle is comprised of fatty acids. They are grouped by three and hook onto a small molecule, the glycerol to form the "triglycerides". These are a little in reserve in muscle. But most of the stock is at a distance, in fat cells in fatty tissue.

The proteins used by the muscle masses are amino acids. They are grouped together in large molecules: proteins. These structures are chemical plants from the cell or form the muscle fibers. Each protein fulfilled a function in the muscle and it does not really exist in the form of storage.

Take stock of inventory!

The glycogen contained in muscles is limited. In athletes of leisure, they are exhausted after about 60 to 90 minutes of running. After a hard training and appropriate eating behavior, they allow for an entire marathon at a good pace. Conversely, grease stocks are inexhaustible. Indeed, even among the most slender of athletes, its thin layer of grease bring energy to run about 700 kilometers!

Exhausting his stock of sugar is hit the "wall"!

The failure on endurance events most often comes from the depletion of glycogen stores. Indeed, fats are burned in the presence of sugar as a glucose derivative involved in the burning of fatty acids. So when the muscle sugar reserves are empty, the engine stops: the "marathon of the wall." This mishap often occurs in the neophyte and the experienced runner trap sometimes. As during a petrol car, all is well until the tank is empty. In a few meters, the wake becomes chaotic. The muscles stiffen and suffer pain or cramps. This sudden failure glue runner bitumen. After the 30th or the 35th kilometer, you can see those who have not enough stored glycogen. They walk on the roadside or trot painfully. They try to stretch or drink energy drinks. Nothing worked ... They look at their watch and stopwatch are in suffering, mourning this performance as expected! Yet they have much ingested a little starchy but they have not read a good book explaining how to optimize their supply before the test!

How to train to avoid the depletion of reserves?

Beyond nutrition, amply developed in the heart of this book, there are some simple rules to limit the depletion of glycogen stock and reduce the risk of default on long trials.

- In trotting, walking or pedaling at a moderate intensity, without being out of breath, muscle learns to use more fat. The mixture used contains more fatty acids and less glucose. That spares glycogen stores.

- When running or pedaling to medium, perceiving a slight increase in respiratory rate, body gradually empty glycogen stores. In response, he learns to increase its stock.

- Running or more pedaling at higher intensity, ultimately shortness of breath, the body learns to less lactic acid. Thus, each glucose is burned more completely and combustion provides 19 times more energy! Again, this chemical adaptation saves glycogen.

Each session is aimed at soliciting one of the limiting factors of performance. Again, this is a varied workout that is useful.

Sugar liver and muscle sugar: to each his mission!

Glucose from the liver to the blood and brain!

liver glycogen reserves only serve to maintain a constant level of glucose in the blood and avoid hypoglycemia. Indeed, the brain is known to use as sugar and its operation requires continuous availability of this precious substance in the blood. Also, to optimize the functioning of the nervous system, glucose he penetrates very easily and freely in neurons. However, it hardly goes into the muscles because it must cross the cell membrane by slipping into channels that limit the speed of passage. Clearly, the glucose in the liver but also that provided by energy drinks during the event, does not bring a lot of energy to the muscles, it can not compensate for the depletion of intramuscular glycogen reserves, it does comes not treat the "marathon of the wall." The glucose in the liver and drinks you can avoid hypoglycemia but it contributes only moderately to muscle contraction.

Glucose muscle for muscle contraction!

The specialization of sugar storekeepers organs finally has a few advantages. You understood, through this regulation, physical activity rarely causes hypoglycemia and brain defects. But you also discover that the intramuscular glycogen does not help regulate sugar levels in the blood. In contrast to liver cells, muscle fibers lack the enzyme for the glucose output. Thus, the sugar stored in the muscles is reserved for the sport! It accumulates quietly until the next effort. By ingesting carbs right after training or in the days preceding a competition, you actively store glycogen and you keep it for your next exercise. So do not hesitate, you can eat copiously "sugars" for the 3 days prior your marathon, time spent at rest will cause reduction of reserves!

Use protein for energy,
it is heat the house by burning the furniture!

Proteins are made available to the body to make energy that near exhaustion. Wait until the discharge body, corticosteroids, potent stress hormone capable of stimulating the destruction of proteins. Indeed, as you know, there are no storage protein shape and use of amino acids for energy means start a carnage in muscle cells! We must break down the muscle fibers! It must burn enzymes for chemical reactions! It is understood that the body can program this possibility last resort. This process begins if you insist especially after hitting the "wall of the marathon." In these circumstances, chemical aggression is associated to mechanical attacks every stride to cause unbearable aches tomorrow. Cell damage is major because all amino acids can not be transformed into glucose and provide energy. It is sometimes necessary to crush a protein to get some amino acids able to burn easily! To limit the "proteolysis" or "protein destruction" during exercise, you need to put enough sugar available in muscle glycogen stores up and making a glucose drink throughout the test. A protein intake during the previous meal the start, especially in the form of reduced dairy, would also be effective. Some scientists believe it may be beneficial to propose, during the year long-term, small proteins containing amino acids called "branched" easily converted into glucose.

Glucose is the "super" fat is the "diesel".

A glucose molecule contains six carbon atoms, 12 carbon hydrogens and 6 oxygen atoms. The presence of the latter that makes you understand that this sugar is already slightly oxidized! A fatty acid substantially contains only carbon and hydrogen. So it takes a lot less oxygen to burn glucose as fatty acids! Thus for the same work the heart and lungs, for the same consumption of oxygen, glucose provides 1.5 times more energy than fat.

You understand why, on high, when the body begins to lack oxygen, muscles preferentially consume glucose. However, when the activity is more moderate, cardiovascular system provides enough oxygen and muscle can consume more fat. Clearly, when you run the 10,000 meters you type only in glycogen stores. However, during a walking tour, you consume a maximum of fat. Half way, if you want to do a good time on marathon, you consume a mixture of sugar and fat whose proportions depend on your talent for endurance, your training, your diet and the status of your reservations!

Your ability to use fat is very dependent on your genetic makeup. Indeed, if nature has given to the muscles of a person enough specialized enzymes in burning fat, he manages to save his glycogen. You know also an endurance athlete able to run for hours without stopping while never consume starchy. Go think ... This is the dog sled or Yuschi! These marathoners ice do not enjoy any cereal crop on the ice and just eats oily fish!

Fat is well worth!

You know, the glucose has a higher yield fat. By consuming much oxygen, more energy is obtained by burning sugar in concommant fat. At the same heart rate, it runs faster if the mixture used is rich in glucose. However, this fuel has two drawbacks. First, the tank is limited: to roll back "wall", the body is forced to use a mixture of sugar and fat. Second, store glycogen significantly increases the athlete's body.

Sugar is a "hydrophilic" substance, "loves water" and dissolves easily. Your sugar dissolves completely in your coffee, each glucose molecule creates electric links with many water molecules that allow it to remain suspended in the liquid. The same happens in your muscles. Thousands of glucose links interconnected as glycogen are bonded to a plurality of water molecules. Finally set aside for 1 gram of sugar, it is necessary to store water and 3 grams heavier body than 4 grams. As 1 gram of sugar provides 4 kilocalories, carbohydrate transported each kilocalorie weighs 1 gram.
Conversely, the fat substance is a "hydrophobic". She "does not like water." Water and grease do not mix and whipped cream floats on irish-coffe. Fatty acids are stored in fat cells in the form of droplets substantially free of water. As one gram of fat provides 9 kilocalories, each kilocalorie transported lipid weighs 1/9 of a gram or 0.11 grams. Sugar is 9 times heavier than fat. So take a race with solid reserves to the brim makes you take 3 to 4 kilos. And even if they disappear gradually throughout the test, you will carry them. If you do not totally deplete your stock you conveyed unnecessary kilos!
Your athletic body is comparable to a Formula 1. Do not overload the meteor with an excess of gasoline. Do not cross the line with gallons of unused fuel. Better manage pit stops and finish the race dry tank. Ideally, the marathon runner must hit the "wall" passing under the banner "arrival".

How to increase the use of fat?

You understand, do not abuse the glycogen stock! Therefore, it is necessary to learn how to burn fat. The long trips to moderate intensity, including cycling, found here an excellent indication.

You know the "sugars" tend to turn into fat. At the diligent athlete, it seems that the triglycerides from the "sugars" preferentially store in the muscles in the form of micro-droplets. These fatty acids reserves would be more easily mobilized for muscle contraction that located far away fat in fat cells. Also, can the regular sports enjoy a little indulgence deal with sweets. Even turned into fat, sugary products appear to contribute to endurance performance.

In contrast, a high-fat diet has not proved effective in increasing the proportion of fat consumed with exercise. Eating too much fat can not save glycogen, or back the "Wall of the marathon." A study in Alpine Hunters attempted to assess the interest of a fat intake during exercise to save the sugar reserves. These soldiers were to reach the top of a mountain. Half of the workforce enjoyed a drink of traditional sweet effort. The other group was fed with "TCM" or "medium chain triglycerides" fat supposedly digestible. Obviously the "sweet group" won the event! The other hit the "wall" and have experienced nausea! Indeed, the ability to consume fat does not depend on the amount of fatty acids available but the equipment in "Enzymes fat burners" present in the muscle cell.

Being overweight does not appear to increase the use of fat. If you are the victim of excess weight if you exercise to lose weight, you can not deny yourself completely starchy if you want to lose weight through physical activity ...

Doctor St├ęphane CASCUA. - 18 f├ęvrier 2010.

Conflicts of interest: the author or authors have no conflicts of interest concerning the data published in this article.


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The Iroman lack of iron, the other sports too!

Doctor St├ęphane CASCUA.

Iron is essential to your health and performance. It is a central component of hemoglobin. The latter is contained in red blood cells and gives it color. It is the iron that captures oxygen when blood passes through the lungs. It carries the precious gas to muscles. When they arrived, it drops its cargo which then allows the burning of energy substances and muscle contraction.

When you run or when you jump, your heels hit the ground and the fat pad of the foot of the plant is crushed. It is through many blood vessels. These red blood cells burst and release their hemoglobin. Iron is released into the blood and pass into urine.

Muscle contains a twin sister of hemoglobin, myoglobin. The latter also contains a lot of iron which sets some oxygen. This small local reserve allows starting the contraction before the blood vessels do not provide the necessary complement. When you experience aches, your muscle membranes are victims of micro-fissures. Myoglobin and iron leaves the muscle and gaining the blood. The precious metal is eliminated in the urine.

When you make an effort, the majority of blood flow is directed towards your muscles. There remains very little to the digestive tract and the bladder wall. These organs suffer from lack of oxygen and are shaken with every stride. Small areas are damaged and start to bleed. Red blood cells and iron are lost in the feces and in urine.

You enter the assiduous why athletes often lack iron, especially if they do not take care to concoct "menus and recipes" adapted. Sports are even more concerned since all these iron losses are added the massive elimination of blood during menstruation!

That is why it is good to occasionally perform a blood test to assess the stock in body iron. This levy is necessary when it comes to review a state of fatigue. It unnecessary to dose iron in the blood because the body is able to keep within the limits of normal while the reserves are at their lowest! It is necessary to measure levels of "serum ferritin" because this structure is the storage form of iron.

The bone is strengthened or crack in contact sports

Doctor St├ęphane CASCUA.

Each sports movement constitutes a solicitation for the bone structure. At each reception process, the tibia runner undergoes vibratory impacts. Unrolling not, the hiker twists slightly small bone in his foot. Even the body-builders, powerfully contracting its muscles, pulls on his bone.

Each strain injures a little bone of sports. Fortunately, during the rest period, the bone trying to rebuild. If time allows, if they bring him the necessary food, it is repaired! It reconstructs even louder than before as if to prepare for new mechanical attacks. This phenomenon is called by coaches cycle decompensation / overcompensation. This process has been described in many body organs and functions: muscle, stock energy, hormones, etc. It is a key driver of growth.

Thus, it was shown that the well-trained marathoner had stronger bones than sedentary. Indeed, its more dense bone structure, higher in fiber and calcium. In addition, the microscopic architecture of the bone is perfectly oriented along the axis of mechanical stresses.

Indeed, the chemical structure of the bone is comparable to reinforced concrete. The protein network is the steel rods. Calcium is comparable to concrete mired these metal axes. At the hip and pelvis direction of the bone structure is very characteristic. On a radiograph, it is found that the fibers leave the femur, the thigh bone, tilt in, come from hip to withstand the weight of the body resting on the hips. The lines of force from the right leg and left leg meet in the middle of the basin and support each other in the manner of the nave of a church.

Physical activity associated with a sufficiently high protein diet, vitamin D and calcium is a great engine of bone construction. This cocktail is particularly useful to hinge periods of life. During growth, it is necessary to eat 4-5 dairy products every day to build strong bones. It should also move: it is essential to practice a sport requiring the running and jumping at least 3 times a week for 30 minutes. In the absence of impact, bones harden less. It has been shown that a young competitive swimmer had lower bone density than sedentary because he was deprived of gravity during those long hours of pool training. In addition, bone densification stops 25 years. At this age you have made up your bone capital for life!

In adulthood, sport reinforces very hard bone and the amount of calcium necessary for the maintenance of bone is still debated. In case of fracture, the rest of the broken area needed a few weeks to allow to "ensnare" the broken area. In addition, gradually increasing mechanical stress are indispensable to "mechanize" the callus. Again, they help to guide the fabric of the bone in the center of the constraints to prepare him for his mission. An increase in calcium intake in consolidation period is proposed by some doctors without that interest has been really shown.

After menopause, the bone structure is gradually degraded to make the brittle bones is osteoporosis. Ladies, remember, your resistance to hip fracture depends on your diet and your sport for 25 years! If physical activity after menopause can no longer denser bones, reduces the loss of bone tissue. So it is advisable to go see jumping around or jog. It is also good to make the soft gym to maintain bone strength to strength. To make the most of this stimulation, it is again necessary to take 4-5 dairy products daily. It should also go out every day to enjoy the sun and make the vitamin D essential for the absorption and calcium binding. Fresh coordinating sports such as Thai Chi or "balance workshops" have proven effective in reducing the risk of falls and fractures.

If the sporting activity is excessive, the micro-cracks caused by impacts on the bones fail to consolidate over the rest. Rather, these lesions worsen in the next workout. Finally the splits right through bone, it breaks without any violent trauma. It is the stress fracture. In a postmenopausal woman, it was demonstrated that 6 hours of sport load per week may be sufficient to break insidiously bones. Among younger adults, this type of injury is favored by dietary deficiencies and hormonal disorders. Lack of calcium, vitamin D and protein alters the rebuild bone victim of microcracks in the exercise. Insufficiency sex hormones reduces the stimulation microscopic chemical plants be responsible for the synthesis of bone tissue. Functional changes occur when the deep depletion of the body. That kind of burnout is most often diagnosed in women because it causes menstrual irregularities and a cessation of menses. The victim is found in a state of "early menopause". In humans this hormone suffering is more insidious but it exists and its effects on bone density are comparable. The sports overwork cocktail, dietary deficiencies and disappearance of rules typically found in young women anorexic. Faced with a stress fracture, the sports physician must remain vigilant. It should not simply treat a "bone". It has an obligation to support a whole person, he is responsible for seeking overtraining or behavioral disorders.

Technical cruciate ligament

By Dr. Nicolas Lefevre

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