écor·chéey-kawr-shey - noun
an anatomical model of part or all of the human body with the skin removed, to allow study of the underlying musculature.
Anatomy....If you plan on sculpting the human figure then make no bones about it (....*groan*...pun intended ;-) you really need to know and understand anatomy.
It's a good idea to to try your hand at sculpting individual muscles in order to truly gain an understanding of what is happening under the skin. This exercise pays huge dividends when you sculpt because as you make the forms, you'll begin to understand how these bones, muscles and tendons give life, emotion and expression to your art.
This will infuse your work with greater authority and sculpting from life, or your imagination will become easier.
You can take workshops or classes if you have the time and availability, but if that isn't feasible, roll up your sleeves and get to work on your own.
Some books that I find useful for anatomy:
The Human Figure (David K. Rubins)
Classic Human Anatomy* (Valerie Winslow)
Anatomy for the Artist (Sarah Simblet)
*I especially like how this book is broken down and the phonetic help.