Exercise and sport tests
Chapter 1 : The athlete's physical aptitude tests
The purpose of the stress tests is to assess the quality of the training or the cardiological non-indication against exercise. They are numerous, more or less sophisticated and difficult to interpret. They are only useful if they can be interpreted directly on the field by the coach and the athlete.
The purpose of this file is to briefly present , at first, the most used tests. The interpretation of some of them will be developed in a later issue of Médecins du sport.
I - General
At the start of the sports season, which coincides with the resumption of the school year, the doctor is asked by the athlete (or his parents) to obtain a medical certificate of no contraindication to the practice of a sport - incorrectly called a certificate of fitness.
More and more often, this request is accompanied by a federal circular imposing certain examinations in addition to the clinical examination, in particular the performance of a stress test.
In addition, the doctor who ensures the follow-up of a team is called upon by the trainer to carry out stress tests intended to estimate the more or less good form of the athletes.
Until recently (1970), doctors performed their own tests - Ruffier, Chignon, Astrand, Margaria tests, VO2 max measurement - and trainers used others - Cooper tests, vertical relaxation, use of pulses in recovery - without always being able to compare them. The technological evolution of the last quarter of a century and the better knowledge of the effects of training and its programming have been at the origin of a multiplication of stress tests by medical teams or coaching teams. Today, it is sometimes difficult to navigate. We will therefore try to make a critical analysis of some of the most requested tests, in view of our dual experience as a doctor for Insep and national teams.
The main stress tests
M anaerobic étabolisme : Test relaxing ve rticale / Margaria Testing / Test load / speed test Wingate Metabolism Aerobic : VO2 max / Aerobic Capacity
II - Why stress tests ?
A stress test is intended to assess or measure the physical ability of an athlete from the study of physical performance or cardio-respiratory and muscular functions.
Some are more of an interest to the doctor, and others to the trainer. But, whether they are simple or sophisticated, it is necessary to always keep in mind that they must be able to be immediately understandable and usable by the athlete and his trainer. Thus, the expression in watts or in joules of an exercise power is not always "meaningful" in the field.
Finally, we must not forget that any stress test is preceded by an interrogation and a clinical examination of which we will say a few words.
III - The general aptitude test
The simplest of the tests requires little material and can be done in the office. This is what any "aptitude" visit should be at a minimum. It begins with an interrogation thanks to which it is possible to know sometimes more than with all the functional tests, starting from questions as simple as : How do you feel ? Are you taking any medication at the moment ? Do you sleep well ? Are you eating normally now ? Do you have gynecological problems ?
At the end of the clinical examination, it is useful to record the resting electrocardiogram and to measure the blood pressure. Then, with the athlete still connected, the Ruffier test is performed : 30 flexions in 45 seconds, and the ECG and BP are recorded again at the end of the exercise and then one minute after stopping the exercise. . The calculation of one of the three Ruffier indices - modified or not by Dickson - is of no interest. It has long been shown that there is no correlation between this index and physical performance.
On the other hand, the interest of this test lies in the presence or absence of abnormalities of the ECG and the BP at rest, during exertion or during recovery. Whether it is a question of elevated heart rate or blood pressure figures, or even of electrical tracing disorders, the question must be asked : “Why these anomalies ?” Which of course refers to the analysis of the training and any specialist consultations.
Maximum values Maximum
values reached by athletes from national teams seen at INSEP during stress tests (averages)
Finally, the analysis of the disturbances of the ECG tracing, as they have been described by Plas, Chignon and Leclercq, and in particular the qualitative analysis of the training which was made of them, must be interpreted with great caution, to not to say abandoned.
A - Tests aimed at evaluating anaerobic power
1 - Vertical expansion test (Sargent test, 1921)
The height of the jump with feet together - assessed from the movement of the head - and the weight of the subject's body give an idea of the maximum anaerobic power. This test is easy to perform, but is there any point in not associating it with a force platform ? Power (Watts) = 0.002 x weight (kg) x Ah (cm).
2 - Margaria Test (1966)
The test consisting in measuring the time taken to climb a staircase of ten steps between two photoelectric cells was used at one time. Is it really relevant ? Its realization is not without danger when you miss a step. Power (Watts) = 0.01 x weight (kg) x speed (m.sec-1)
3 - Speed load test (1979)
It requires an ergocycle suitable for measuring the speed of rotation as a function of the increasing load which brakes the wheel. Anaerobic power is expressed from values extrapolated to zero speed and maximum force. This test certainly depends on the subject's maximum anaerobic power, but also on his motivation.
4 - Wingate test (1980)
That's 30 seconds of pedaling at maximum speed against a constant load set according to the subject's weight - typically 75g per kilogram of body weight. The maximum anaerobic power is obtained by multiplying the peak speed by the braking load. You can also use the average power over 30 seconds or the area under the curve. The successful completion of this test depends a lot on the motivation of the subject.
5 - In summary
The equipment used and the production protocols being variable, it is difficult to establish reference standards. The only interest of the tests is to compare the individual in relation to himself.
Even easily reproducible, these tests have three drawbacks.
- Being maximum, they strongly depend on the motivation of the subject.
- They are far from the usual gestures.
- More annoying : they are difficult to decipher by the athlete and the trainer.
Therefore, it seems to me much easier to use field tests such as the following ones.
- Maximum speed run over 20 or 30 m , the stopwatch being triggered when the rear foot leaves the ground. This test is more precise if photocells are available, but the first version with the trainer's stopwatch is often sufficient. This test can be adapted to other sports (cycling, swimming ...).
- Muscle strength test at maximum load. To be carried out by progressive loads on one or more movements known to the athlete. The advantage of these two examples is that they are easily achievable with unsophisticated equipment on sports fields. The interpretation of these tests is particularly simple.
B - Tests exploring the aerobic metabolism (maximum aerobic power and anaerobic threshold)
These tests are designed to measure or assess VO2 max (maximum oxygen uptake). The success of VO2 max is due to the long thought that its value was linked to the physical condition of the individual. On the other hand, the direct measurement of VO2 max has always been - and still remains today - limited by the cost of the analyzers. This is why indirect methods of evaluating VO2 max from other measurements (heart rate, exercise power) are still used.
Post a Comment