[ojbyrne]

High altitude has been well known as a training aid for decades, e.g. Kenyan marathoners: https://www.cnn.com/2019/11/06/africa/kenya-runners-win-mara...

[latchkey]

The US Olympic Training Center is in Colorado Springs, Colorado.

Elevation: 6k ft and next to Peaks Pike at 14k feet.

I used to go there in the late 80's as a cyclist to train.

They'd follow you in a car as you rode up PP, honking at you to go faster.