In short, the researchers found that even with several years of anabolic steroid withdrawal and a lack of strength training, important characteristics of muscle were permanently altered.
Examining the muscles of former powerlifters who have used steroids in the past, but not for several years, their muscle fiber size remains elevated. And importantly the number of nuclei per muscle fiber remains comparable to the lifters currently training and using steroids, and significantly higher than lifters who are currently training and had never used steroids. While this higher number of nuclei per fiber is only one aspect controlling muscle adaptability to training, it is likely to be highly beneficial to an athlete who resumes training. Previous steroid use, even years earlier, will allow for more protein synthesis, faster protein deposition, and more rapid increases in muscle mass and strength.
Eriksson, A., Kadi, F., Malm, C. and Thornell, L. (2005). Skeletal
muscle morphology in power-lifters with and without anabolic steroids.
Histochemistry and Cell Biology, 124(2), pp.167-175.
According to the lead researcher, Dr. Eriksson, ”It is possible that the high number of nuclei we found in the muscle might be beneficial for an athlete who continues or resumes strength training because increased myonuclei opens up the possibility of increasing protein synthesis, which can lead to muscle mass.” He added, “Based on the characteristics between doped and non-doped power lifters, we conclude that a period of anabolic steroid usage is an advantage for a power lifter in competition, even several years after they stop taking a doping drug.”