Not that this revolutionary or anything, but I've always had a hard time loading heavy on the seated calf raises. I'm doing Chad W's 25 Method, which calls for seated calf raises and I've chosen the 4 x 6 rep scheme for that day. I can load over 300 lbs, almost all of my home gym weight and easily push out 20 reps.
For some reason today, i had the brilliant idea of doing these 1 leg at a time. I don't have to put as much weight, and struggle with getting the bar into position. Just pad the bar and set it on the working leg. After 6 reps switch over to the other leg while using your arms to help balance the weight.
It definately was harder and more stimulating, like many other 1 limb exercises. Just thought I would share my epiphany, try it out. I don't know why I didn't think of this years ago, sometimes movements just come to you about the gym at the oddest times.