Stop looking at the watch during your easy runs and start thinking about whether you are running slow enough. An easy run should be conversational and a pace you feel like you could run forever at.
While reading Matt Fitzergerald's new book, "80/20 Running: Run Stronger and Race Faster by Trainig Slower" to review on Diets and Review's website I was reminded that most of us run our easy runs wayyyyyyyy too fast. During training, when a workout calls for an Easy Run or a Recovery Run embrace the slow, comfortable pace and stop trying to push the pace boundary. SLOW runs are just as important, if not more, than your speed work.
It might be hard at first to break the habit of pushing it a little more than you should on easy days, but with a little bit of dedication and focus, easier, easy runs might be just what you need to get that spring back in your legs.