Former Manchester United assistant manager Rui Faria has spoken on the topic of GPS vests to track player data.
Faria, who is now 47, was Jose Mourinho's assistant at Manchester United and at other clubs.
Newspaper reports stated that at time Mourinho was in charge at United, they were the only club to not use GPS vests to track player numbers in training.
Faria, speaking on the TGG Podcast, said: "First of all, I have nothing against GPS, but you cannot reduce performance to GPS. Today, GPS is a good tool, especially if you don't understand anything about the physiology of the game.
"There is a huge tendency to have GPS controlling the sessions. You have sessions where sport scientists go on the pitch and stop the coach from coaching, because the numbers are going over the numbers they have as a reference. This is so ridiculous that everyone is losing the logic of coaching. At that moment we felt it was good for us not to use it.
"We knew things that had happened in the club in the past, so the decision came from that. Also, it was a tool we felt we didn't need to use because of our experience and knowledge of the game."