One of the main causes of medial tibial stress syndrome (the proper name for shin splints) is doing too much, too soon. And, being injured is the biggest running-motivation buzzkill. In fact, among the 203 participants that kept track of post-injury motivation, 22 reported that they were less or not at all motivated to start back up again. So, even when you’re mentally ready to turn your 5K, 10K, or half-marathon dreams into a reality, being overly ambitious with your mileage can leave you spending more time on your couch than speeding to the finish line.