I'd be hugely surprised if it's not commonplace in football sadly. Some of the statistics you see through the PL season are mind-boggling if you think about the consistency with which they're taking place regarding high intensity sprints, distance covered and diminishing (not increasing) injuries.
What I always found odd was the idea that we as fans have accepted that there's a hug gap in fitness between some teams and others when, realistically, it's far more likely that all PL teams would be extremely close together if measured purely for fitness given how advanced sports science is and how much money is in the PL. You can argue that facilities make a difference but to what point - all PL teams will have world class gyms, nutritionists, trainers and all the paraphernalia that comes with it. I'm sure Carrington has more saunas and masseuses than the Colney Training Centre (Norwich FYI) but you only need to look at Brighton's new setup to see how every team is now 'state-of-the-art' if there is a difference it will be minuscule.
Of course it would be a disaster if this came out but I just see it as an arms race now - I'm certain Pep is up to his eyeballs with PEDs, Klopp and Poch for sure and now Ole is starting to look at this style of constant pressing, very high intensity football I guess we'll be looking for every edge we can find. It's well documented how difficult it is to test for and there's so much money in football, finding every advantage possible is literally worth millions of pounds that it would be weird if it was not rife.