If, on a random Tuesday at 5:30 a.m. as I tied my shoes and set my Garmin, someone said that she expected me to run a six-mile route at a pace one minute per mile faster than the speed at which I typically run—and for readers who aren't runners, that's no mean feat—I'd respond that expectations aren't reality.

Ouch. Yuck. Pain.

Yet that's exactly what happens on race days. I'm a speed demon. And it doesn't even feel that difficult.

What is it about a starting line, race bib, and a crowd that makes me run faster more easily than I could on a regular day?

In fact, a race atmosphere makes everyone run at a comparative clip. Some runners credit people cheering from the sideline and the adrenaline of competition. For me, it's an instinctual need to get away from the herd—being in a crowded field of runners makes me anxious. Though I won't deny that loudspeakers blasting music and people clapping help with motivation.

Could I do six miles on an average day at my typical 10K race pace? Probably, but it would feel a lot more miserable.

Further proof that, more than anything else, running is a mental game.

I've been running for a number of years now and I do at least a few races a year. Yet I still marvel at this phenomenon. And it makes me wonder: In what other areas am I psyching myself out of doing as much as I actually can?

How do we hold ourselves back? And how can we mend our ways?