Most running injuries don’t erupt from nowhere and blindside you. They produce signals—aches, soreness, and persistent pain—but it’s up to you to listen to them and take appropriate action. Plain and simple: If something hurts, do not run. As soon as you start to feel an injury coming on, stop running and rest for a few days. Once the pain is completely gone, you can slowly resume running.
At the first sign of an atypical pain (discomfort that worsens during a run or causes you to alter your gait), take three days off. Substitute light walking, bicycling, or another cross-training activity if you want. On the fourth day, run half your normal easy-day amount at a much slower pace than usual. If your run is pain-free, you can try running a little farther the next day. If you are still pain-free, continue easing back into your normal routine. If not, take another three days off, then repeat the process to see if it works the second time around. If not, you’ve got two options: Take more time off, and/or schedule an appointment with a physio therapist.