Former Manchester City fitness coach Raymond Verheijen has blasted the fitness training of Premier League clubs.
Verheijen, 39, said: "They called Robben the man of glass when he was at Chelsea. Last year he played with Bayern Munich. What they did was reduce his training volume. He played the best football of his career. They won the title because of him.
"All of a sudden he was not injured anymore. The question is, 'Was he a player of glass or was he trained by coaches of glass?' Arjen Robben and all the other explosive players, like Robin van Persie, when they make an action they use more energy than other players.
"If they train the same volume as the other players their energy expenditure is twice as high as the other players. So you have to reduce the training volume by 50 per cent, which is what Bayern Munich did with his programme."