The concept of muscle loss is something that I've never really been able to consolidate into a 'functional' understanding. I have some idea of the theory -- but I figured it would be great to cast my questions out to the Tnation community and get some answers from experience, not research papers.
Might also make for an interesting discussion...
As far as I know, muscle loss should take place in one of two situations:
1) Severe caloric deficit (so the body cannibalizes muscle tissue)
2) Long periods of disuse (muscles atrophy when not trained...)
My question pertains to no.2 -- I'm interested in the extent to which disuse has to take place, in order for atrophy to occur.
Suppose a lifter had three lagging body parts -- shoulders, biceps and calves. This lifter trained using a typical bodybuilding split, focused around the key movements -- squats, deads, OHPs, pull-ups, rows, etc. -- but this lifter seldom had time for isolation movements (hence the lagging body parts). In order to address the first of the deficits, the lifter then decided to add bicep isolation movements to two of his weekly sessions. After 10 weeks (or whatever) the lifter found that his biceps had developed sufficiently and wanted to use the time previously dedicated to the bicep isolation movements for calf isolation movements. He then ceased all bicep isolation movements to free up the time. This lifter's biceps would still be trained every week -- in pull-ups, rows, upright rows on shoulder day, etc.
Is it likely that this lifter's increased bicep size would remain, due to the stimulation from the compound movements? Or is it likely that this lifter would lose some (not all) of the added bicep size, due to the 'relatively' decreased usage?
I'm sure that all experienced members here have had periods where they prioritized a particular body part and can shed some light on this issue.
I appreciate any input. Thanks.
Oh, and before someone asks -- yes, the hypothetical situation does somewhat pertain to my real situation, and yes, I will be using the input from this discussion when planning the path forward.