I know this sounds crazy, but we used to jump rope. Man talk about a calf pump afterwards (not to mention good aerobics). If done right, you can isolate one calf from the other. Do you play sports? Basketball or something like that that require you to jump? Me being in the Martial Arts and Volleyball addict, my calves always get a workout runnin in sand and jumping all the time. I do calf raises on my days off, just to get my jump higher and build my calves. But nothing like jumping rope (the correct way).