A little rough and tumble

Play as a boy is very important and goes beyond merely the physical exhaustion of 'rough and tumble' but is an important part in their bonding letting out and asserting their masculinity in front of their peers while it is affirmed.
Timid boys need to helped into 'play fighting' to form good bonds learning to control their strength and handle aggression so they feel confident socially as males with a stake in society.
 While the 'fear factor' and the tendency to see boys as 'a problem' because they don't confirm in the main to female stereotypes has lead to more restrictions in the playground it simply needs to be recognized boys ARE different, they ARE a gender apart and it's better to direct that than in effect de-gender them.