I am from rural Alaska, and what sent chills up MY spine was her running on a mountainside. We've all done it, but it's a really, really bad idea.

What's a bit lost in translation is that what she calls a "mountain rush" (山駆け) actually refers to an ascetic practice by Yamabushi monks.

The typical ascetic practice of Yamabushi is mountain running, which involves walking for several days through steep mountain paths while reciting sutras.

In the old days, the training was so severe that dropping out of the training meant death.

It doesn't mean she's running all the way up the mountain. She's just climbing (walking up) the mountain twice a day, which is already impressive.

That was the cultural note of the day.

Thanks! I also did a lot of running up and down large stairs, again, like they did in Love Live!, something I wouldn't recommend people do, but mountains are very dangerous. I lived not all that far from Denali Park, where there is a broad range of mountains, some of which have snow on them year 'round.

I've done quite a bit of trail running in the alps, and while it does take some getting used to, it does feel quite safe to me (of course it depends on the path etc.).