It means you can start chewing on your butt again. This is the pets/veterinary forum, right? No.... wait.... Oh.... nevermind.

Try not to put the cart before the horse, cross the river before you come to it, yadda, yadda.... As with being in a cast, your muscles are still making micro-adjustments, so any loss and time to regain will likely be less than you fear.
http://www.quora.com/Is-it-easier-to...uscle-mass-Why

Google: how long to regain muscle and similar keywords

Doc