There must be a SIGNAL sent, consistently, for your brain to think it’s necessary to grow a muscle (training)
A signal that makes your brain go:
“Hm, I’m not worried about survival, but life would definitely be easier if we had more muscle on Eric’s arms… he keeps bending his elbow against resistance on Tuesdays and Fridays (bicep curl)… “
I notice he’s giving me adequate protein, and he won’t stop bending his elbow… Like he’s actually doing more elbow bends every week and this could cause us some problems down the line if we don’t adapt… I want this elbow bending to be easier… let’s allocate some resources to his elbow bending muscles.”
The ONLY reason your brain would deem building muscle necessary is if our surviving and thriving depended on it. The body only ever makes adaptations if it will increase our chances of doing those two things in our environment. If it is doesn’t aid in surviving or thriving, you won’t adapt.
So, to grow our arms… what must we do to make our brain think we will thrive better in this world with more muscle?
Progressively overload a given exercise for 6-8 weeks.
3×10 the first week, 3×10-12 the next session that week, maybe more weight
4×8 the second week, 4×8-10 next session week two, maybe more weight
4×10 third week, 4×10-12 next session, maybe more weight…
Do this for long enough, and your brain will deem adding muscle necessary for surviving and thriving.
When in doubt, training pretty hard works. Your goal each session, or each week, is to give your body slightly more volume (sets x reps x weight).