Thanks hub… I think. @Slowwithouttwitch it’s actually not driven by substrate oxidation, it’s about maintenance of energy state. While lactate is used as a marker for FTP, in metabolic reality there’s no causal link with it. As for your flippant stating of “progressive overload” you’re going to have to define the substance of what you mean since there are a few potential ways to apply overload, and we can clear this up instead of watching all of you talk past each other.