Popular devices for monitoring physical activity, such as smart watches and sports wristbands, often base their predictions on maximum values, which are not measured directly, but predicted based on various formulas. Polish research has shown that these models do not always accurately reflect actual values, especially in the population of more physically active people. Their results suggest that the tools can both underestimate and overestimate the intensity of effort, which leads to imprecise training planning, body fatigue or lack of effects.

'Such devices cannot replace exercise tests and you should not be plan your training based on them. For example, it is not uncommon for a watch to define your activity as very demanding, while in reality it is moderately tiring and ineffective or, on the contrary, practically maximum', says Przemysław Kasiak, a doctoral candidate at the Medical University of Warsaw and one of the authors of the NOODLE study.

As part of the NOODLE (predictioN mOdels fOr enDurance athLetEs) research cycle, scientists analysed the precision of current predictive methods used in sports equipment. Their work resulted in four scientific publications in the following journals: BMC Sports Science, Medicine and Rehabilitation, Journal of Clinical Medicine, Frontiers in Physiology and Scientific Reports.

The research was conducted on a group of physically active people and endurance athletes. Key parameters analysed in the project included: minute ventilation/carbon dioxide production ratio (VE/VCO2-slope), peak oxygen pulse (O2Ppeak), oxygen uptake efficiency slope (OUES) and oxygen uptake efficiency plateau (OUEP). Each of these indicators plays an important role in assessing the physical performance of the body and can be used in both sports and clinical medicine.

After summarizing the results of all four studies, it turned out that popular predictive models used in physical effort monitoring devices are often inaccurate, especially in the case of professional athletes. 'Wristbands and watches do not measure our performance parameters directly, they only predict them. They determine the maximum values ​​based on various formulas and estimated equations, which in many cases turn out not to reflect the actual capabilities of the body', Przemysław Kasiak emphasises.

He points out that the greatest deviations between actual and predicted values ​​occur in people with a high level of training. For people who train amateurishly, not very intensively and occasionally, sports watches and wristbands can often be sufficient.

'Our previous studies showed that a sports watch is much more misleading in the case of a trained person than a person who is less trained. In the latter case, all the values ​​are simply much lower and easier to predict', Kasiak says.

One of the interesting conclusions from the NOODLE project was that the oxygen uptake efficiency plateau (OUEP) indicator - unlike other exercise parameters - is quite stable in all people, regardless of the level of training. This suggests that it can be used as one of the more objective elements of performance assessment.

'OUEP is a very interesting variable. Because, for example, in the case of VO2max, the more trained a person is, the higher the value of this indicator. This means that people who do not exercise and are sick have low VO2max, athletes - high. It is different with OUEP, which remains at a stable level in everyone, regardless of fitness. It only drops during illness. It can therefore be a very interesting addition to the more well-known parameters that are taken into account in athletes', Kasiak says.

The results of the NOODLE study also provided new information on the possibility of correcting existing predictive models to better reflect the individual characteristics of athletes. In one of the papers, the researcher presents a method for calibrating the FRIEND model, which allows for more precise prediction adjustment to different populations. 'As we described in Scientific Reports, this method can be used in all training groups', he emphasises. 'This opens up new possibilities for monitoring training in both professional athletes and amateurs', he adds.

The researcher explains that such monitoring is important because learning and appropriately regulating physiological parameters is crucial in sports. 'It is essential for optimal training planning. Performance analysis allows to not only track the pace of progress, but also minimise the risk of injury and health problems related to excessive strain on the body. And although in the NOODLE project we focused mainly on endurance athletes, the conclusions from these studies may also be important for people who practice sports as amateurs', he says.

In his opinion, every person should do an exercise test with oxygen uptake analysis at least once in their life. People who train as amateurs but regularly should do it once a year or every two years.

'If you do not know when training is too hard for you, and you repeat it regularly, you will overtrain, which is associated with an increased risk of injury, fatigue, decreased motivation, lack of effects and withdrawal from physical activity. In extreme cases, this may even end in serious cardiological events', he points out.

According to the expert, further development of research on physical performance will be important for the future of sports and medicine. Measuring devices will become increasingly personalised and based on advanced solutions. In order for them to be created, it is necessary to understand the mechanisms regulating the body's performance, including precise analysis of physiological parameters and improvement of predictive algorithms.

Katarzyna Czechowicz (PAP)

PAP - Science in Poland

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