What Eq. techniques had champions used before the invention of "mouthfill"?

I'm very surprised to learn that such an important technique "mouthfill" was just invented by Eric Fattah in the Y2K (published at Frenzel-Fattah Equalizing Workshop), just about a decade before!!! So my big question is that before the Y2K what equalization techniques had world champions used to reach great depths such as 101m (no limit) of Jaques Mayol as early as 1976???

Jaques Mayol had a normal lung (not an "oversize lung" like Pipin's or Umberto's). If as in normal cases, his lung reached Residual Volume at 30m - 40m and he could stretch his eardrum to bare further 50% pressure, he could only dive down to 60m - 70m. How did classic champions like Mayol deal with the last 30m - 40m? Can any one explain it to me?

Thank you, Simos, for the valuable information, esp. "The last equalisation".

Personally, my limit on Valsalva was 10m, then I moved to Frenzel which helped me another 10m, then I usually take my mouthfill at 20m for using at another 10m (I haven't had chance diving deeper than 30m yet). After much training on thoracic diaphragm and relaxation, now I get back to Valsalva for testing and it just extends a few more meters. My problem is <b><i>how to get air into the mouth-nose carvity</i> when your lung's air has got negative pressure (i.e. "empty", precisely <i>RV</i>)</b>. I've tried "empty-lung diving" (both FRC and RV), but after RV I can only use air left in my mouth (from previous mouthfill). My biggest problem is that <i>any attempt to "suck" more air after RV caused my trachea to squeeze!</i>

Someone may say "let's reverse-pack!" But I've tried it and the result is so frustrated: On land after exhaling to RV, I can easily get 5 more mouthfills with reverse-packing. But the point is that the negative pressure I feel after that 5 reverse-packings has nothing to compare with the negative pressure (mostly on my throat) I feel when diving below RV. So it's obvious that I cannot do any reverse-packing after passing RV (only simulated by empty-lung diving).

I have a fragile trachea (usually caugh), and my first squeeze was at only -4m (at the bottom of the swimming pool) when I practised empty-lung diving. But after that, as I paid attention to the pressure on my throat, not to stress it any more, I could dive down to -30m cleanly (of course with mouthfill). I don't know why, but after my first squeezes (nearly a year ago), my trachea's become more and more fragile... and recently I got some squeezes even... on dry land!!!

(Sorry! This forum seems not allow me to modify/delete my post, so I repost my key points here.)

... My problem is how to get air into the mouth-nose carvity when your lung's air has got negative pressure (i.e. "empty", precisely RV). I've tried "empty-lung diving" (both FRC and RV), but after RV I can only use air left in my mouth (from previous mouthfill). My biggest problem is that any attempt to "suck" more air after RV caused my trachea to squeeze!