Eric Heiden (sp?) the speed skater said he did heavy leg presses, I can't remember the weight now but I think it was 5 or 600 lbs, for 5 sets of 100.
I was close friends with a guy that won the Mr Arizona a number of years ago and he had some of the freakiest legs I have ever seen. He hardly weight trained them. He would crank the stationary bike up so high you could barely turn the pedals and he would ride it for 30-45 minutes. That was his entire leg workout most of the time. He had good development from weight training them already, but when he started that, they blew up.
There is no doubt in my mind that high repetitions with heavy resistance builds huge legs.
Here was a quote directly from him:
"Before the 1980 Olympics it wasn't uncommon for us to do the following:
Find an old truck tire intertube and cut out about one third of the tire (where the valve is). Seal one end by tying and taping with duct tape.
Fill intertube with either lead shot or pennies until alomost full. Seal off other end. I made several sizes but the biggest ones I figured weighed about 150lbs.
Swing the anaconda on your lower back and assume the speed skating position. Do 1 x 100 squats with each leg. Do that 5 x. Then repeat with both legs. Going down to slightly below 90 degrees.
Right after these we would drop the tube then do 15 - 20 squat jumps as high as you can bringing your legs up to your chest a the peak.
Usually the last one you would fall down because you could not support your weight anymore.
Dang, those were the days...and that was only workout number 1. usually we did 3 workouts a day. "
He was also known to do high rep squats and leg presses with heavy weights for high reps , as you mentioned. As with most things, you can't pidgeion hole the training of these guys, it's periodization in all these elite sports.