Sounds like Aden was encouraging David Torrence to get vitamin B injections. Folic acid, a B vitamin, is needed to make red blood cells. It can be depleted under conditions of high stress, causing anemia. Injecting folic acid during periods of intense training would correct a deficiency more efficiently than taking it orally. Also, being the more dramatic route of administration, injecting might cause a greater placebo effect, giving the athlete a psychological boost.
I'm not saying that the injections work or that they were being used judiciously, in fact, I believe Torrence was wise to refuse them. I'm just saying that there's a plausible, legal (?) explanation for Aden encouraging his athletes to receive injections.