change of behaviour

[dawnraider 2]

as you know my new pup broke his leg 2 weeks ago,he is doing well and has addapted really well to his cumbersome cast,but i have noticed a change in hi behaviour,when i got him he was the typical puppy bouncing around into everything a proper little lunatic,but after having to keep him confined and no proper playing he has become a very calm quiet dog who will sit,lay,come and stay on command.all well and good but do you think this could have a negative affect on him as he grows mentally,if so what would be the best course of action he has 4 weeks left with his cast and i would imagine another couple of weeks taking it easy any help much appreciated atb dawnraider