Why Marathon Runners Hit the Wall
The gist
Marathon runners hit the wall because their bodies run out of glycogen stores, which are the main source of energy during long-distance running.
Explain like I'm 5
It's like a car running out of gas; when runners use up their stored energy, they get really tired and slow down a lot.
Big picture
Understanding why runners hit the wall helps athletes plan their nutrition and pacing to avoid sudden exhaustion and improve endurance during marathons.