On the morning of Memorial Day, I found myself soaked in sweat, laying flat on my stomach, head-pounding, arms shaking as I closed in on finishing the prescribed 200 push-ups. I was not alone. Surrounding me in the austere and sweltering warehouse-like gym were a few dozen people, all battling the heat to labor through hundreds of push-ups, pull-ups and air squats, bookended by mile-long runs.
