My experience as an instructor is that, by far, the most of injuries happen to people who did not manage to equalize.
I evaluate the risk that a diver "over equalizes" doing a Valsalva with excessive pressure is quite smaller than the risk of not equalizing.
The point is that 2/3 of my students who were struggling to equalize were attempting to do it using Valsalva. And for most of them the problem was solved teaching them another method (different for each of them).
So yes, Valsalva does well for a large number of beginners. But it also fails for a significant number of them (more specifically for those on the low end of the bell curve, those with problematic tubes). So a good instructor needs to manage other equalizing methods, and to be able to train the students to use them, when Valsalva fails. Or, better, even when Valsalva works, but something else works better.
We are all different, and it is better to know various methods, and to use the one working better.
I evaluate the risk that a diver "over equalizes" doing a Valsalva with excessive pressure is quite smaller than the risk of not equalizing.
The point is that 2/3 of my students who were struggling to equalize were attempting to do it using Valsalva. And for most of them the problem was solved teaching them another method (different for each of them).
So yes, Valsalva does well for a large number of beginners. But it also fails for a significant number of them (more specifically for those on the low end of the bell curve, those with problematic tubes). So a good instructor needs to manage other equalizing methods, and to be able to train the students to use them, when Valsalva fails. Or, better, even when Valsalva works, but something else works better.
We are all different, and it is better to know various methods, and to use the one working better.