I have had experience with a weak calf. My non dominant calf was weaker than my dominant, I eventually found it was from lack of flexibility in my ankle, which I blew out about 6 years ago.
I used compound movements (squats, box jumps, etc) along with a lot of ankle mobility to even out my calves.
My question is does anyone have experience with directly isolating the weak muscle or group to bring it back to par with the other? how did it work?