Always thought this a bit of a made up nonsense, truth is when you fall you will automatically and naturally just let go of whatever you are holding. But yes charging around with the stabby bit first isn’t wise.
On the subject of things teachers say, my garden backs onto a High School playing field, and I work from home, hence it’s an endless source of intrigue listening to the various goings on.
One day a PE teacher on a particularly hot day was chastising a group of girls for complaining that they were too hot. They were actually fortunate, the teacher asserted, that their uniform was black, as this would help keep them cool. Hence why you see Black Hijabs.
Most amusing. But it did remind me of some of the duff info I received at school.