We talk about data. Not even sure how we would be able to tell much from the data. How much natural variance would one get when it comes to muscular injuries? This one can tell with some certainty of course. I have seen some numbers, but I have not seen any statistical analysis of it. Then you got other factors that are not related to fatigue due to playing to much. How much of that increase is caused by the shortened pre-season? Just as an example. I would love to see that analysis - so this is not me being sarcastic.
The next would be an analysis of the value of 5 subs. I have had some muscle injuries myself and I cannot say I have ever gotten one which I knew was coming. So it is not like I felt a bit tired 60 mins into the game and therefore asked to be subbed to avoid an injury. That might happen of course, I wouldn't know, but I do not believe that is how these normally come about. If that is true (or partly true) then the 5 subs rule would be more to control long term fatigue. Which is also something you can control with squad rotation. I struggle to see why this is seemingly so important for Liverpool and Liverpool fans. Not because I am against the rule, but to me Klopp and Liverpool are making far too much out of this.