Former Wales assistant manager Raymond Verheijen has labelled Manchester United manager David Moyes and his coaching staff 'dinosaurs' following an injury to striker Robin van Persie.
The Netherlands international suffered a thigh problem during United's 3-2 defeat to the Yokohama F. Marinos on Tuesday.
While Moyes has claimed that the blow is not serious, Verheijen believes that the Scotsman has pushed the 29-year-old too hard.
The Dutch coach wrote on Twitter: "In Sydney Moyes said, 'We've over-trained Robin this week to build up his fitness'. Then he picks up a muscle injury. What do you expect? Players like Van Persie should learn to protect themselves against 'overtraining' and 'punishing training'.
"You have to ask how these prehistoric training methods are still used at the highest level. The only way to solve this problem in Jurassic Park is to improve education of these dinosaur coaches, fitness clowns and scientific cowboys.
"As long as most dinosaurs are still in denialand ignore how things develop in other countries, nothing will change in Jurassic Park."
Meanwhile, United have claimed that unsettled striker Wayne Rooney, who has been linked with a move to Chelsea, will return to pre-season in Sweden on August 6.
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