As for the arms. Lets not start, because the arm contribution is from a natural swing and carriage that is reactionary to running. We can’t increase the force contribution with active arm movements but we can dampen it. I guess this is a chicken and egg one but go ahead start a new thread. I may or may not participate. I almost hate the subject as messing with arms will dampen vertical force production and not enhance it.
Can you please provide some evidence to support this claim that all that can be done is dampen it? Conversely couldn’t we also say the same about lower body force contribution (that there’s a maximum achieved when mechanics are efficient but that it’s ‘dampened’ when they are not?).