Once I rode my coach's bike (80s aluminum Vitus with Modolo plastic downtube shifters) and that bike had a neat auto-shift feature. When you stood and pedaled hard enough with poor pedaling form (which I had in spades as a teenager), the small-diameter aluminum tubes (which were glued to the lugs) would flex so much, it would pull on the shift cable, which would cause an upshift, and even shift the lever for you. That bike was light as a fart, but flexy as all get-out.
My coach was a pretty smart guy (with impeccable pedaling form) so in criteriums, he would simply stomp on the pedals briefly while accelerating and the bike would automatically upshift. Gave him a leg-iup while everyone else is seated and reaching for their downtubes.
He'd simply snug down the tension on the shift lever if it was a hilly race, and of course engage his flawless pedaling form.
He is Mark Fletcher of Esprit Velo Club. A remarkable guy.
