some kind soul bent the ground adjustable trim tab on a Cessna 150 of all things.
a mate was PIC and we went out for a fly to a local restorer of Tiger Moths.
on the flight back my mate asked me to put my foot on the right rudder so that he could give his leg a rest.
at my questioning it eventuated that he had lost muscle control of his right leg and had quietly poked his left foot on the right rudder. when this eventually also gave out he had both feet on the right rudder and both his legs had lost muscle control.
my right leg lasted a few minutes then I had both legs on the right rudder and finally we flew the aircraft with both of us with both legs pressed on the right rudder.
all because the little ground adjustable trim tab on the rudder had been bent to about twice its angle.
so Vmca is one thing. the elephant here is the question of just how long you could actually push hard on the rudder. the need doesnt diminish but the ability of human muscles to push sure diminishes.
...I'll go back to sleep....