He feels John's work since coming to the club at Glenn's behest has been excellent and explains:
"I believe the players are very fit at the moment, certainly if you look at how strongly we have finished in the last two games.
"We were able to carry the game to Manchester United right until the 86th minute when we got that equaliser.
"John has been working hard now for over a year in terms of getting the players' levels of fitness up, getting a bank of physical fitness and making the legs strong.
"We felt we had to increase the depth of fitness that the players had to make sure they have good reserves to call upon."
He stresses it has been a long term project and adds:
"It can't be done overnight, only over a period of time of at least 12 months and we would like to think we are very modern in our physical conditioning techniques.
"You can't bring a sports scientist in and expect them to be 100% fit and him knowing what is going on with each individual's body after three sessions.
"We hope we are up there with the very best in terms of conditioning the players and no one can have any complaints that we don't finish games strongly in the last 15 or 20 minutes - that is due to John's work.
"We call John our fitness coach but we are undercooking him there; he is a fully fledged sports scientist."
The title is an apt one and Glenn reveals that a technological approach is needed:
"Everything we do in terms of fitness goes on the laptop; we record everything they do physically in their running sessions on to it, and I can go to John and we can look at the fitness levels of any player.
"He can draw that up on the laptop and show me exactly where they are compared to last year.
"Now he has got the data and I can look at any player; let's say I thought their form had dipped a little bit my first port of call would be to check their fitness; John can show me that fitness may not be the reason and there are probably other factors involved.
"And similarly if he thought any of the players' fitness was dipping he would come and see me and we would take an individual fitness programme for him.
"We have proved that the levels of fitness have improved; we know we have strengthened their legs and their upper bodies."
Glenn says that John has a good personal relationship with the players and adds:
"The good thing is now he has got to know the players and their different characteristics - and he gets on very well with them, which is a bonus.
"I think they like this sort of scientific approach now, and you have got to remember a lot of the younger players have grown up with computers themselves, so it is natural for them to look at a laptop screen and see what the picture is.
"Some are more interested than others but you get someone like Christian Dailly and he literally wants to know exactly what is going on in his body, what his fitness levels are, and what he can do to improve.
"There are others like him who are minded like that, and it is why players can easily continue into their mid-30s if they look after their bodies now."
Glenn is satisfied that the players who were at the England get together did not waste their time in the week and adds:
"Both David and Trevor enjoyed the three days and the practice game that they had at Aylesbury and felt it was a very useful time - it is about team building, team bonding.
"They went to Buckingham Palace to meet the Queen which I have been very fortunate to have done myself after France '98 - let's be fair, it is a big honour to be invited there.
"And they certainly did enough in the session on Thursday when they returned - it was plenty physical."