^^

lots of discussion generated re quad lutz. Guys were obviously practicing the quad lutz during training sessions, but who knows exactly when certain guys actually began landing it in training sessions? Did Plushy, Joubert and Yags perform quad toes mostly? Quad-toe seems to be the first quad for many quadsters, and then the salchow first landed by Tim Goebel.
[Edit] According to Wiki, the first quad ever landed by Kurt Browning was a quad
toe loop. And interestingly, the first triple jump ever landed by Dick Button was a loop.
The first quad flip was landed by Shoma Uno in 2016. The lutz was outer limits until recently. In fact, when quads first began to be landed, there was not a lot of discussion as to what kind of jumps were being landed. When skaters performed the extra revolution it was mainly referred to as simply being a quad, as if that was some kind of new jump in and of itself. The quad is simply an extra revolution added to a basic jump. I spoke about that a few years back and then there were IN articles in which guys discussed some of the differences between the basic jumps and why that extra revolution is so challenging. Then commentators began to focus more on naming the type of quad that was being landed.
There doesn't seem to be any solid documentation of training sessions involving successful quad lutz efforts among senior competitive skaters over the years. That would be difficult to track, unless there was some kind of organized coordination re practice & training reports.
Of course Brandon Mroz was the first to land the quad lutz in competition, as I already noted in post #247 in this thread. Still, Adam Rippon as a popularly known skater, made a concerted effort to land the quad lutz (due to its point value and his facility with the triple lutz) before Boyang Jin moved up to seniors and slayed in the points with his fully rotated 4 lutz/triple. That was Jin's calling card and his ticket to the podium as a newbie senior (who still needed to work on other aspects of his skating). The message was sent to all the younger guys that mastering 4 lutz/triple is how to break through in a big way. Nathan Chen had the talent, great jumping technique and chutzpah to heed the message.
The below site lists some of the firsts regarding figure skating jumps, but it is not up-to-date re quad-lutz/triple (Jin Boyang) and the first man to land five clean quads in a single performance (Nathan Chen):
http://www.jacksonskates.com/html/jumphist.html
Wiki has updated more recent records re landing quadruple jumps in figure skating, but the list still fails to include the fact that Evan Lysacek landed a quad/triple at U.S. Nationals in 2007. Lysacek also landed quads in international competition, but he didn't need to land a quad jump to win 2010 Olympics, even though his winning without one was used by peeved Plushenko to set off a controversy that led to Patrick Chan mastering quad toe, and quads being overweighted in the scoring. The rest is quad-mania history.
https://en.wikipedia.org/wiki/Quad_(figure_skating)