Add more calf exercises to lower-body workouts

Even Arnold had to work very hard on developing his calves. Truly a great leg day is simple: Quads, Hamstrings, and calves.

[Note from Carl: On the split program, the lower body B workout already has an exercise for calves. Calves are trained indirectly on other workouts days. Chris would like to see more direct calf work on those days.]