Nicky Butt has revealed that Manchester United have used a circus performer and parkour trainer to help develop players at their academy.
The former United midfielder, who was named the club's academy head in February, says the current restrictions as a result of "health and safety" concerns have limited the natural development of today's players.
Butt told The Times: "I see players in our academy and they can't move. Our lads don't know how to fall, roll and you should see the amount of injuries we get from popped shoulders or their arms."
He added: "I probably fell out of a tree 15 times and never hurt myself. I don't think my son has ever climbed a tree. Body mechanics lose so much when you're not climbing trees, not playing basketball, cricket and rugby.
"This might sound bizarre but we've had a guy come in from the circus, telling the kids how to do spinning plates, jumping through hoops, circus tricks to get their biomechanics working.
"We had a free runner, the 'parkour' lads who jump over buildings, set up a course."