5. Run a PR.
A PR doesn’t always have to happen at a goal race that you put down on your calendar months ago. And that potentially means that, even without too much specific fine-tuning, you might find yourself in the best running shape of your life at some point this summer and pop off a personal best when you least expect it.
By running a 5K to half marathon midway through your training cycle, you not only get a great all-out workout that stokes your competitive fire, you also get a huge confidence boost (especially if you approach or set a PR). You might consider tapering a bit before a key race to ensure maximum results, but you could always use your non-key races to kick off a weekend of high-intensity training.