Running does things to you. It builds stamina, increases confidence, improves mental health and has a profound effect on your overall fitness.

Or, in my case, it gives you one overweening ego. 

I don't know why I think being a runner makes my lower body invincible to the pain ordinary mortals may experience, but it does. It's why I continue to remain shocked at how horrible I am at spinning. It's also why I'm reluctant to admit--at midnight on a Friday--that my glutes, hamstrings, and thighs are KILLING me, compliments of Jillian Michaels.