Pump set question

[Dahmkooler]

Before I forget - do you have a link the article / post Helms wrote on this topic?...

So, there's the topic of locus of fatigue here - central (brain) vs. muscular vs. various subtleties in between (reflexive inhibition, excitation-contraction failure e.g. at the neuromuscular junction, etc., etc. etc.).

The bottom line falls back on progress and choosing a Volume Tier which permits this (i.e., that you can recover from).

Back to the topic: The idea of true mechanical failure would be supported by the notion that if you were to superimpose e-stim upon a contraction at the point of failure, that you'd not have an increase in force output. There are some major issues with using this approach (you can look into twitch interpolation and central activation ratio if interested), b/c you'll find, for instance that you can come up with conclusion that untrained subjects (during a maximal effort - not at the end of a set per se) can supposedly fully activate a muscle voluntarily, but we know that if you take those folks and train them for a few months, strenght goes up substantially, in a way that simply is not possible solely due to an increase in muscle mass - it's a neurological phenomenon.

The point of the above it that there's likely a wide range to the extent to which subjects and trainees can push through pain and put the locus of fatigue on the muscle vs. a psychological reason, so the presuming there's a kind of state that can be reached where failure is purely mechanical (in the muscle) is likely an oversimplication.

Instead, there is probably varying degrees to which pain influences performance as well as the inhibitory influences, e.g., via Type III and IV sensory receptors (see link below) are inhibiting and changing motor output in a way that least to fatigue.

ALSO, the idea with Pump Sets is to create metabolic stress so if you're carrying that out (it sound like you are) and not bringing those sets to some sort of mechanical failure, that's probably not a huge issue b/c the mechanical tension does'nt seem to be the stimulus that's vital to high rep sets. (Take occlusion training, for instance). The other Set Types of FT are more so set up to create a mechanical (tensile) overload stimulus.

And I do agree with you on the topic of untrained folks pushing harder (even with in-the-lab encouragement) gym rats, but there's a lot of overlap there, too.

Last thing is that your you muscle fatiguabilty might he higher (more type II fiber, for instance) such that you're getting a very substantial metabolic stress from the Pump sets (and rapid onset of fatigue), which *could* mean that you're getting a great stimulus for growth from Pump Sets for your legs. OTOH, it could be just be a central (CNS) issue in that you're not quite able to create the neural drive for the larger musculature of the lower body (compared to the upper body work), or even that there is some cardiorespiratory influence here (you're gassing out).

ALl of the above really still comes down to VOlume Tier and exercise selection, order in particular).

I'm not sure which Tier(s) you're using, but you might find that you can shift the locus of fatigue towards the muscle and away from any cardiorepiratory / central loci by doing isolation exercise (e.g., knee ext. and ham curls) before doing compound thigh movements.

-S


https://www.ncbi.nlm.nih.gov/pubmed/3730936

I know it gets said a lot, but it's really hard to believe how incredible a resource this forum is - thanks for taking the time to reply Scott!

Here is the article by Helms:
https://www.strongerbyscience.com/low-load-training/

I think you answered all of my questions and gave me plenty to chew on . I am using Basic Tier II, and have always done compound thigh exercises first for pump sets. I will try adjusting exercise order next time and put quad/hamstring Iso's first. I also think the cardiorespiratory factor could be present, because I'm currently at the heaviest weight I've ever carried, and I do get gassed out pretty easily (my shirt is completely drenched usually ~1/4 through my workout!).