Here’s an excellent body weight exercise that mimics the seated machine calf raise. Squatting calf raises work the soleus muscle, which is primarily slow-twitch, so super high reps are best.
For more secret muscle building exercises, check out STRENGTH AND PHYSIQUE: HIGH TENSION EXERCISES FOR MUSCULAR GROWTH:
http://www.amazon.com/Strength-Physique-Tension-Exercises-Muscular/dp/148027058X/ref=sr_1_1?s=books&ie=UTF8&qid=1352582069&sr=1-1&keywords=strength+and+physique%3A+high+tension+exercises+for+muscular+growth
Also check out http://strengthandphysique.blogspot.com/
