The First Two Weeks of Cross Country Practice: What I'm Actually Watching For

Losing just 2% of body weight through sweat is enough to measurably hurt performance, and that's an easy number to hit on a hot practice day, often before a runner even feels thirsty.

Most of the fueling advice aimed at teenage runners is either too complicated or borrowed from adult elite athletes. Here's what I actually tell the parents of the high schoolers I coach.