Sorry for the noob question...

If I'm only training each muscle group once per week, how many sets should I be doing ?

(until now I was working each muscle group twice per week, 20 sets on large muscle groups (10 sets per workout session) and 16 sets on small muscle groups (8 sets per workout session).

A general guideline is 9-12 sets for big body parts (legs, chest, back), and 6-9 for smaller ones (tris, bis). So, IMO, what you were doing during your twice-a-week sessions seems right on. Of course, like everything, set numbers are highly variable. So many individual factors come into play (experience, goals, split, intensity/load, rest between sets, etc) that these numbers could be way off.

I'd recommend doing some research on this. Here are some links to get you started:

Lots of different splits (with set info) -- scroll down to find yours (http://forum.bodybuilding.com/showthread.php?threadid=143006)

Sets and Reps (http://www.bodybuilding.com/fun/ice2.htm)

Beginner's Guide to Weight Training (http://www.elitefitness.com/forum/showthread.php?s=&threadid=273138)

Hope it helps. :gl:

:confused: Now I have too many options ...