Well the Caps routinely demolish teams in the 3rd period, they have a bunch of 2 goal or more comebacks in the 3rd period, so I don't think they are out of shape, which means its not coaching or conditioning.
The concern is their lack of focus at the beginning of games, but that appears to have receded a bit in the last few, certainly last night. I'll say it again, the Caps appear to play hard only when they need to, which I am still holding out hope that its to save gas for the playoffs. The only way to know for sure is to see if they can play all 60 minutes in the first round. Or maybe a handful of games down the stretch.