Which measuring methods are available?
Pulse, blood pressure and lactate measurement: To test the endurance and resilience of the cardiovascular function, easy to determine parameters such as pulse rate, breathing and blood pressure are suitable. As the oxygen demand in the musculature increases during exercise, the respiratory rate, the heartbeat volume and the pulse increase. In addition, the vessels dilate so that metabolic waste such as lactic acid (lactate) can be removed. Optimal endurance training takes place at the so-called threshold pulse, which is also referred to as steady state or aerobic-anaerobic threshold (ANS). This is the point at which the pulse and lactate level settle to a certain equilibrium, where just enough oxygen is available to the musculature to burn and therefore produce energy from carbohydrates and fat ("aerobic" = with air).
Threshold pulse and lactic acid concentration
If the load increases, the muscle cells no longer receive sufficient oxygen and must change their metabolism to anaerobic energy production ("anaerobic" = without air); lactate is increasingly produced and exhaustion quickly results.
- The threshold pulse, and thus the level of exertion, is individually different and depends primarily on age and resting heart rate (which is higher in children, women and the untrained), the frequency with which it is exercised and, within limits, the type of sport. Rest and pulse changes also vary depending on the form of the day, stress, weather, illness and medication. The pulse measurement can be carried out by the layman without effort and automatically with measuring devices that z. B. be strapped to the wrist.
- Characteristics of a good state of training and performance are a low resting heart rate, a high threshold pulse and that the pulse quickly returns to its normal level after completion of training.
- The rough guideline for the optimal pulse rate during endurance training is 180 minus age.
- The concentration of lactic acid in the blood before, during and after exercise provides information about the current metabolic status. For measurement, blood is taken from the earlobe. The lactate value is related to the respective pulse and plotted on a graph (lactate power curve). The assessment remains for professionals such. B. in sports clinics, which can determine the performance based on the diagram and develop specific training proposals.
In addition to measurements of pulse, blood pressure and lactate, ergometry (stress ECG) is used as a direct functional measurement. Under stress (eg on a bicycle, treadmill or stepper) the work performed, the individual maximum performance and physical reactions are measured by means of blood pressure, pulse and cardiac current curve. The load that is started and its increase up to a defined maximum value ("workload") depends on the gender, the ability to lead and possibly the type of sport being practiced. However, if complaints or fatigue or dangerous ECG changes occur subjectively (indicating, for example, heart problems), the examination is terminated before the exercise is exhausted. Ergometry is also used for aftercare in heart attack patients.
Thus, the individual exertion can be determined. The subject rated on a scale of 6 to 20 how hard he currently feels - depending on his subjective breathlessness. This sensation correlates well with the objective measured variables such as pulse (about Borg value times 10), oxygen uptake and lactate values and thus offers a good possibility to estimate the own training state without measuring devices.
There are also specific procedures that primarily analyze how the cardiovascular system and respiration interact. This includes z. As the lung function measurement, in which the respiratory rate, the respiratory minute and tidal volume and the oxygen uptake are determined. It is coupled as spiroergometry with ergometry. Because they require more sophisticated equipment, they are reserved for specific issues.
In the performance diagnostics for endurance athletes there are a number of other procedures that are used in addition to or instead of the established lactate performance test and are usually an evolution of ergometry or spiroergometry, which therefore no blood sampling is needed. These include, for example, the Conconi test, PWC test, ramp test, Polar OwnZone test or the isokinetic maximum force test.