Start Slow, Stay Athletic
The start of a new training cycle, particularly after a period of at least two weeks of no running, should include almost exclusively slow, easy running. The aerobic adaptations from doing this, and from running slow and easy as a predominant activity throughout training, are well-known:
This first phase of training can take several weeks and months to fully benefit from, but despite having so much slow and easy running there is no reason to neglect your athleticism. In fact, by keeping your athleticism intact throughout the base-building phase you may find your stride regains and retains efficiency much quicker and much easier.
Athleticism for runners can be defined as the ability to quickly and powerfully apply and absorb force in a specific and efficient direction relative to the goal of the movement. To keep this aspect of your fitness we are talking running drills, plyometrics, and short fast strides.
So, if building back up from a recent race and subsequent time off, start slow, but be able to snap fast.