When you get right down to it, running is not about being comfortable; it's about pushing limits. And tempo runs are designed to do just that and in the process make you a stronger, faster runner. In a tempo run, you aim to run faster than your usual pace for an extended period of time, unlike intervals, where shortish periods of pushing yourself hard are followed by periods of slow running for recovery. But tempo runs are typically short, with only 20 minutes of running "comfortably hard," as ultramarathoner Dean Karnazes puts it, with a solid running warmup prior to pushing yourself and a easy-pace cooldown after. Ready to try one? Here are tips on how to find your pace and a structure to follow for your first run. Spoiler: for your first tempo run, aim to run at speed for only 10 minutes and increase the time as you get stronger.