How do we think about failure?
I was watching some content on getting to or close to failure, and I am trying to understand how or if this even correlates to overcoming isometrics.
Failure is not being able to move a fixed weight, but with isometrics we are never moving any weight. What is the equivalent of isotonic failure in the isometric world? Are we always reaching failure as long as we are theoretically producing the most force possible for as long as possible?
I am interested in being able to pin this down because it can be difficult to know when enough is enough, for a certain workout/exercise, without simply tracking weights over time.
Edit: I did the research I should have done before I posted. I guess RDR, Repetition duration reserve, is the CNS equivalent of muscular failure... so from 3-10 sec, one has basically used up 100% RDR.