Steroids and Muscle Development

A well conducted study by Bhasin et.,al (1996) explored the effects of  supraphysiologic doses of testosterone on muscle strength and body composition. The study consisted of 43 males between 19-40 years of age who were assigned to one of four groups: placebo but no exercise; testosterone but no exercise; placebo plus exercise; testosterone plus exercise. They were given either 600mg of testosterone enanthate once a week or a placebo. The exercise subjects underwent supervised weight training three times a week.

Figure 3: Source (Bhasin et al.,1996. p6)

Changes from Base Line in Mean (±SE) Fat-free Mass, Triceps and Quadriceps Cross-Sectional Areas, and Muscle Strength in the Bench-Press and Squatting Exercises over the 10 Weeks of Treatment (Bhasin et al.,1996).
The P values shown are for the comparison between the change indicated and a change of zero. The asterisks indicate P<0.05 for the comparison between the change indicated and that in either no-exercise group; the daggers, P<0.05 for the comparison between the change indicated and that in the group assigned to placebo with no exercise; and the double daggers, P<0.05 for the comparison between the change indicated and the changes in all three other groups (Bhasin et al.,1996).

The graphs in figure 1 shows a significant increase in one rep max for the testosterone alone and placebo-plus-exercise groups for squatting. The graphs also show a significant increase (P<0.001) in one repetition maximum in the testosterone plus exercise group for both squat (38%) and bench-press (22%). Furthermore there is a significant increase in both Quadriceps area (1200mm2) and fat free mass (6.1kg) in the same group. Even though fat free mass increased this was attributed to an increase in lean mass and not a decrease in fat.  These important results indicate that supraphysiologic doses of testosterone coupled with strength training will significantly increase fat free mass, strength and muscle size. This is one of the few studies designed and conducted with sound scientific parameters that provide definitive conclusions.

The reasons for an increase in strength and muscle size are likely due to an increase in protein synthesis. Anabolism itself is defined as any state in which nitrogen is differentially retained in lean body mass, either through stimulation of protein synthesis and/or decreased in protein breakdown (Kuhn CM 2002). AAS binds to an androgen receptor in the cell which eventually leads to the cell nucleus increasing the rate of protein translation and then transcription. This is due to the nucleus producing ribonucleic acid (RNA) at a faster rate. The mechanism of this action is still not entirely known however as the anabolic effects of androgens on muscle is unclear and may involve mechanisms independent of the androgen receptor (Wu 1997).  What is known is that a dose-dependent increase in muscle protein synthesis leads to hypertrophy associated with an increase in the cross-sectional area of both type I and type II fibres and an increase in myonuclear number (Kam, P.C.A: Yarrow, M. 2005). An increase in type II fibre CSA is beneficial to sprinters and strength athletes in particular. An investigation by Hartgens et.,al (2002) on the effects of ASS misuse on deltoid muscle fibre characteristics found  an increase in mean muscle of type I fibres (+10.8%) and type II (+14.6%) muscle fibres after an 8 week cycle of supraphysiologic doses of ASS. The study also investigated AAS effects at therapeutic doses which showed no change in muscle fibre diameter.  These results suggest that ASS at supraphysiologic doses have a more profound effect on type II (fast twitch) muscle fibres. However the diameter of both the type I fibres (P<0.10) and type II fibres (P<0.07) fail to show a significant difference. This confirms that increases in muscle fibre size due to AAS are dose dependent and its still unclear wither type I or type II fibres are more profoundly affected.

For muscle fibre hypertrophy to occur there needs to be an enhanced recruitment of myonuclei from satellite cells. This occurs through satellite cell activation and proliferation in response to muscle damage occurred during strength training alone, but is enhanced by the use of anabolic steroids and is more prevalent in the trapezius than in the vastus lateralis according to F, Kadi (2000). This is due to increased Androgen-receptor (AR) containing myonuclei in the trapezius which insinuates training, and the anabolic affects are muscle dependent. An additional study by Kadi et.,al (2000) on androgen receptors in human neck and limb muscles found that androgen-receptor containing myonuclei in the trapezius was higher after long term strength training combined with ASS rather than in strength training alone or in untrained subjects (P<0.05). In conjunction, there was no difference in AR content for all three groups in the vastus lateralis but there was an increase in myonuclear number for both the trapezius and vastus lateralis muscles. Therefore this further suggests that an increase in androgen receptor-containg myonuclei is muscle dependent.

An increase in muscle fibre hypertrophy in the upper body has mixed benefits for athletes. It improves body composition especially around the neck and shoulder area but has little sporting relevance. Some athletes in sports requiring exceptional shoulder and neck strength (wrestling, baseball, American football, rugby, mma etc) may see improved performance with increased muscle fibre recruitment through AAS use but further study is needed to reach any conclusions.

However, although AAS increases muscle fibre hypertrophy it may not necessarily result in increased strength. Even though the evidence in figure 1 shows and increase in strength though testosterone use, only 50% of the investigations show significant improvements in strength measurements with steroid treatment (Lamb Dr, 1984.) As previously mentioned studies on the effects AAS have shown that any results are likely to be dose dependent which may explain why some investigations report no strength improvements.

End of Steroid Research Introduction