In a lactate test, the so-called lactate level in the blood is determined in order to determine a person's fitness level.
Lactate is produced directly in the muscles and is a salt of lactic acid. A person's lactate level at rest is one milli mol (mmol) of lactate per liter of blood. This value can rise to 25 mmol of lactate per liter of blood during exercise.
This metabolic product is produced during intense endurance exercise, at the beginning of heavy static muscle work and during high-speed strength stress (longer sprint distances).
The energy required for this is mainly produced by splitting ATP. ATP is adenosine triphosphate, to put it simply, a very high-energy molecule.
It is important that when energy is provided by ATP, a hydrogen ion (proton) is split off and remains in the muscle. A certain number of this proton (H +) can lower the pH value.
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The pH of the muscles is usually neutral (7). If the value falls below seven, then one speaks of an acidic pH value. Lowering the pH value can lead to cell damage. Because of this, the body has developed a defense mechanism. In order to bind the protons, the body produces more lactate.
Read more on the topic: PH value
During the formation, protons are bound and the over-acidification of the muscles is counteracted. This protective mechanism will eventually reach its limits. If the pH value in the muscle cell continues to drop while the number of protons continues to rise, then the protons ultimately block the splitting of ATP and the muscle cramps (colloquially: closes).
The lactate ensures that a highly intense exercise can be continued for a certain time before the muscle cramps. The more lactate there is in the blood, the higher the number of protons in the muscle and the higher the stress on the body. The level of stress can be determined on the basis of the lactate in the blood and the body's ability to maintain intense stress for a certain period of time.
$config[ads_text2] not foundAt physical stress a distinction is made two metabolic pathways.
For one thing aerobic energy metabolismwhere the Energy supply for the muscles on the basis of oxygen expires.
Aerobic means that oxygen is sufficiently involved in the supply of energy. If the intensity of a training or competition increases, the muscles need more oxygen in order to be able to meet the higher energy requirements.
From a certain intensity the body is no longer capable add even more oxygen, the maximum oxygen uptake has been reached. When this point is reached, the body is at the aerobic-anaerobic threshold (4 mmol threshold).
From this threshold the body begins slowly but steadily using more oxygen than is being supplied to him. The muscle cell is flooded more and more with protons and there are even more Lactate educated. Around individual threshold will determine a Lactate test carried out.
Of the Lactate test belongs to the performance diagnostic procedures to determine endurance of an athlete. The longer a load increases, or can be held upright, the better the endurance of the athlete. Such a performance diagnosis to determine endurance is usually in the form of a Level tests.
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Usually such a step test takes place on the Treadmill instead of. Optionally, a Respiratory gas analysis be carried out in order to collect further parameters. Classically only one Lactate test carried out.
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At a Step test will the Load increased gradually. Before, during and after the level test, the athlete will Blood drawn. A needle is inserted into the ear and then a few drops of blood are taken. This blood is then examined and the existing lactate value is determined. The test will to absolute exhaustion of the athlete performed to next to the aerobic-anaerobic threshold also the maximum lactate concentration detectable in the blood.
A Step test requires certain guidelines that should be adhered to. The Length of test plays an important role. If the individual steps are too long, the Athlete exhausted before his maximum load has reached.
At too short steps it is possible to reach the top speed of the athlete without being exhausted beforehand. A lactate test should therefore always have steps of the same length and these steps should be an appropriate length.
Besides, it can Treadmill can be set with or without a gradient, which in turn has an effect on the step and test length. Next to the treadmill can be a Step test also on one Exercise bike or one Rowing ergometer occur. This depends on the original sport of the athlete.
As a rule, such performance diagnostic level tests can be found in competitive sports. They rarely occur in recreational and popular sports because the effort involved is correspondingly great and trained specialists are required to ensure controlled implementation.
For such a Step test there are several models.
A model includes, for example. 5% incline of the treadmill and starts at 8 km / h. This speed is maintained for three minutes and then every three minutes increased by two km / h. The blood is taken during and after the exercise.
It is similar with the following Standard test. Each stage will five minutes on the treadmill completed and there this time no incline of the treadmill. After each stage will a minute break inserted and blood drawn from the test person to determine the lactate value. The test starts with 3.25 m / s (Meters per second). The increase at each level 0.25 m / s.
A step test should always be included Affinity for the sport be performed. As already described, this can be done by choosing the device, or by the length of the step and the slope. However, it is particularly important to always take a lactate test same conditions and to be carried out with the same settings in order to be able to compare the various individual tests with one another.
The described method of implementation relates to a laboratory. In a laboratory, the conditions can be reproduced at any time, so that the results are perfectly comparable. Often, however, this is too far removed from reality, so that so-called Field tests be performed. These are step tests in the usual environment of the sport (career, rowing boat, etc.).
The evaluation one Lactate tests mainly focuses on that aerobic-anaerobic threshold. It is for them Control of endurance training the most important value, because it shows whether the lactate value is on a Lactate steady state levels off or continues to rise. Lactate steady state means that after each Increased stress to a new level of Lactate value levels in the blood at one level and at this one Level with constant intensity persists.
Will the aerobic-anaerobic threshold reached the lactate steady state disappears and the Blood lactate value rises steadilywithout leveling off at one level. This aerobic-anaerobic threshold is at approx. 4-mmol lactate per liter of blood. This value is not one hundred percent accurate, but it can be used as a guide. You should always note that this threshold is highly individual and can be different for each athlete, depending on the type of sport and training level.
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Has been with one classic step test now the threshold of 4-mmol lactate per liter of blood at 14 km / h one can determine one after a certain training time Repeat test to check whether the training has improved endurance. Reaching the aerobic-anaerobic threshold at 14 km / h is a very good value for a recreational athlete and, in this example, no major improvements can be expected through training.
In a lactate test, the so-called lactate level in the blood is determined in order to determine a person's fitness level. Lactate is produced directly in the muscles and is a salt of lactic acid. The lactate value of a person at rest is one mill mole (mmol) of lactate per liter of blood (1 mmol / l). This value can rise to 25 mmol lactate per liter of blood (25 mmol / l) during exercise. This metabolic product is produced during intense endurance exercise, at the beginning of heavy static muscle work and during high-speed strength stress (longer sprint distances).
The energy required for this is mainly due to the splitting of ATP produced. What exactly ATP is would take up too much space here. It is important, however, that when energy is provided by ATP Hydrogen ion (Proton) is split off and remains in the muscle. A certain number of this proton (H +) can den PH value humiliate. The pH of the muscles is usually neutral (7). If the value falls below seven, then one speaks of one acidic PH value. Lowering the pH value can lead to cell damage. Because of this, the body has developed a defense mechanism. In order to bind the protons, the body produces more Lactate. During the formation, protons are bound and the over-acidification of the muscles is counteracted. This protective mechanism will eventually reach its limits. If the pH value in the muscle cell continues to drop while the number of protons continues to rise, then the protons ultimately block the splitting of ATP and the muscle cramps (colloquially: closes).
The lactate ensures that a highly intense exercise can be continued for a certain time before the muscle cramps. The more lactate there is in the blood, the higher the number of protons in the muscle and the higher it is burden for the body. The level of stress and the ability of the body to maintain intense stress for a certain period of time can be determined from the lactate in the blood.
A distinction is made between two metabolic pathways during physical exertion. For one thing aerobic Energy metabolism, in which the provision of energy for the muscles is based on oxygen expires. Aerobic means that oxygen is sufficiently involved in the supply of energy. If the intensity of a training or competition increases, the muscles need more oxygen in order to be able to meet the higher energy requirements. Above a certain intensity, the body is no longer able to supply more oxygen and maximum oxygen uptake is reached.
When this point is reached, the body is at the aerobic-anaerobic threshold (4 mmol threshold). From this threshold, the body slowly but steadily begins to consume more oxygen than is supplied to it. The muscle cell is increasingly flooded with protons and even more lactate is formed. To determine this individual threshold, a Lactate test carried out. The lactate test is one of the performance diagnostic procedures for determining the endurance of an athlete. The longer a load can be increased or maintained, the better the endurance of the athlete. Such a performance diagnosis to determine endurance is usually in the form of a Level tests. Such a step test usually takes place on the treadmill. A breathing gas analysis can optionally be carried out in order to collect further parameters. Typically, only a lactate test is carried out.
In a step test, the load is increased step by step. Before, during and after the step test, blood is drawn from the athlete. A needle is used to make a small stitch into the ear and then a few drops of blood were taken. This blood is then examined and the lactate value in it is determined. The test is carried out until the athlete is completely exhausted, in addition to the aerobic-anaerobic threshold also the maximum lactate concentration detectable in the blood.
A step test requires certain guidelines that should be adhered to. The length of the test plays an important role. If the individual steps are too long, the athlete can become exhausted before he has reached his maximum load. If the steps are too short, it is possible to reach the athlete's maximum speed without being exhausted beforehand. A lactate test should therefore always have steps of the same length and these steps should be an appropriate length. In addition, the treadmill can be set with or without an incline, which in turn affects the step and test length.
In addition to the treadmill, a step test can also take place on a bicycle ergometer or a rowing ergometer. This depends on the original sport of the athlete. As a rule, such performance diagnostic level tests can be found in competitive sports. They rarely occur in recreational and popular sports, as the effort is correspondingly large and trained specialists are required to ensure a controlled implementation.
There are several models for such a step test. A model includes, for example. 5% incline of the treadmill and starts at a speed of 8 km / h. This speed will three minutes followed and then every three minutes around 2 km / h increased. The blood is taken during and after the exercise.
The situation is similar with the following standard test. Each stage will five minutes Graduated on the treadmill and there this time no incline of the treadmill. After each stage will a minute break inserted and blood drawn from the test person to determine the lactate value. The test starts with 3.25 m / s (Meters per second). The increase at each level is 0.25 m / s.
A level test should always be carried out with an affinity for the sport. As already described, this can be done by choosing the device, or by the length of the step and the slope. However, it is particularly important to always carry out a lactate test under the same conditions and with the same settings in order to be able to compare the various individual tests with one another.
The described method of implementation relates to a laboratory. In a laboratory, the conditions can be reproduced at any time, so that the results are perfectly comparable. Often, however, this is too far removed from reality, so that so-called field tests are also carried out. These are step tests in the usual environment of the sport (career, rowing boat, etc.).
The evaluation of a lactate test mainly focuses on the aerobic-anaerobic threshold. It is the most important value for controlling endurance training, because it shows whether the lactate value is on a Lactate steady state levels off or continues to rise. Lactate steady state means that the lactate level in the blood increases to a new level after each increase in exercise one level levels off and remains at this level with the same intensity.
If the aerobic-anaerobic threshold is reached, the lactate steady state falls away and the blood lactate level increases steadily without leveling off at one level. This aerobic-anaerobic threshold is approx. 4 mmol of lactate per liter of blood. This value is not one hundred percent accurate, but it can be used as a guide. You should always note that this threshold is highly individual and can be different for each athlete, depending on the type of sport and training level.
If the threshold value of 4 mmol lactate per liter of blood at 14 km / h was determined in a classic step test, you can carry out a repetition test after a certain training time to check whether the training has brought an improvement in endurance performance. Reaching the aerobic-anaerobic threshold at 14 km / h is a very good value for a recreational athlete and, in this example, no major improvements can be expected through training.
The lactate value in the blood is displayed in mmol on the y-axis and the stress values of the step test in km / h on the x-axis. The individual threshold is marked with a red dot and is just under four mmol of lactate per liter of blood at just over twelve km / h. The graphic also shows that lactate production increases the longer the test runs and the higher the exercise speed.
The lactate test is one of the standard means for determining endurance performance and must no longer be missing from any performance diagnosis in professional sport.
