K seems very very slow to build muscle, despite the huge number of hours spent training. If the "problem" is chemical/genetic, then perhaps additional chemicals could help "solve" the problem.
blood loading — it's clearly risky, requiring professional nursing skills to make sure the blood remains hygenic while it's stored elsewhere and then reinjected
EPO — the easy version of blood loading, doesn't require re-injection
"Why is EPO dangerous?" — on the other hand, most of these apply to traditional blood loading, so the fact that some militaries consider blood loading to be "safe enough" probably also applies to EPO