Actually, I remember reading a case study with four groups of participants, 2 on Roids, 2 natural.
With all diets being the same varying on body weight.
Group 1 - Natural, not working out.
Group 2 - Weekly injections of 600 mg of testosterone enanthate and Not working out
Group 3 - Natural following a regular gym routine
Group 4 - Weekly injections of 600 mg of testosterone enanthate and following the regular gym routine.
If I remember rightly The results were as expected for group 1, no changes, though group 2 who took steroids and did nothing still gained 7lbs of muscle!!, group 3 gained 4lbs which is about right (Pretty good!) For 10 weeks training and Group 4 I think put on about 12lbs
Literally just got home from work so will have to find a link to the study and get back to you...