The article is very interesting because it provides several information about some of the main devices used in gathering biomechanical and wellness data, giving some reflections and recommendations too! The advent of these instruments has changed the way players train and has granted coaches some measures in order to monitor players during training sessions. Since they are technological systems and are related to health and well being, the responsible use is involved into the discussion. They are useful if they are accompanied by opinions and guidelines from experts and specialists in the sector. Their presence could help people to understand more easily data, which is produced and stored by the devices. In second instance, they have to be controlled and classified as reliable instruments: some data are very sensible and extremely important such as heart rate or heart rate variability (HRV). A false reading of these information could bring further health issues for consumers who can't understand the type of data. So, as the article advises, a consumer should verify whether such technologies are useful or not, even asking advises to an expert. In addition, in many cases these instruments are very expensive and not accessible for all. However, wearables in sport are in continuous evolution and, for me, it will face these challenges in the future: 1. More precise algorithms in order to track in a better way the information; 2. New deep learning systems that will be able to recognize some physical and wellness issues with an high level of reliability and confidence; 3. An higher quality of products offered to the consumers thank to the competitiveness of market; 4. The rising of the number of companies that are interested in research for implementing new tools not the wearable; 5. Introduction of short language models in some devices, also considering the trade-off between model complexity and computational resources owned by the wearable.

This paper is a good starter reading for introducing the topic of data analysis in sports since it has interesting hints that make possible to generate several discussions. One of the crucial points that interested me a lot is the use of wearables in order to track several informations about training performances, player's behavior and so on. For me, thanks to the improvement of IT, maybe in the future we can see advanced wearables with a certain type of display that can give live data on training sessions and game performances, revolutionizing not only the decision making before the matches but also the it can be useful when deciding a new strategy during the game, giving also the possibility to coaches and his staff to organize the matches in a better and a more informed way. Another point I have interested on is the ways of collecting these data. I am a huge tennis fan and I follow the main matches of Italian tennis players and all the matches of the biggest tournaments, such as Masters 1000, Grand Slams and also some 500 ATP Tour tournaments. I tried to make some studies and analysis on players like Federer, Nadal, Tsitsipas and so on. The biggest threat I have encountered when I was doing it is the difficulty of collecting good data. I wanted to make a descriptive analysis and some performance's indicators on different players but there were some problems: firstly the quality of data is good but not enough, secondly free data can only display numer of wins, defeats, aces etc..., which are a bit inconsistent when we are moving into the calculation of an overall index, finally it is impossible to make predictions and to study the player's game style and main attitudes during a game. I hope I will see more statistics applied in the tennis world because, like the football and basketball, tennis player's coaches can receive support in decision making thanks to statistics, even if the overall condition of the player usually depends mostly for the mental condition and mental strength while for the physical condition.