Calorie Surplus, Hypertrophy and Hyperplasia

IronPlayground

I've been thinking about this lately and I may have only confused myself. I figured I'd see what you guys think. I'll try to keep the question short. I hope I get enough info in my question to make it sound logical.

Given normal circumstances aside from newbies and morbidly obese, most people are not going to "gain" muscle eating at a deficit. Going to the surplus side is the way to do this. However, hypertrophy is possible while eating at a deficit, yes? Hyperplasia isn't possible for humans. Eating at a surplus will not cause one to create new muscle fibers.

So, my question is, what are we actually "gaining" while eating at a surplus?

Chief_Rocka

We're looking to increase the *size* of our existing muscle tissue, which is done in two different ways.

Myofibrillar Hypertrophy - Your muscle fibers contain a chain of "myofibrils." You can increase the amount of myofibrils within your muscle tissue through progressive overload. This is generally accomplished in the low to moderate rep ranges.

Sarcoplasmic Hypertrophy - This is an increase in sarcoplasm, a fluid that lies within your muscle cells. This is generally accomplished at the higher rep ranges.

Hyperplasia, the addition of *new* muscle tissue, doesn't occur much it humans, as you mentioned.

Sarauk2sf

Sarcoplasmic hypertrophy creates increases in the size of the existing muscle fibers. It is basically the cells within the muscle fibers that increase, not the number of fibers themselves.

IronPlayground

Right, I knew we couldn't create new fibers.

Does it take a surplus for both myofibrillar hypertrophy and sarcoplasmic hypertrophy to occur?

Chief_Rocka

Right, I knew we couldn't create new fibers.

Does it take a surplus for both myofibrillar hypertrophy and sarcoplasmic hypertrophy to occur?

It does.

Increasing the size of muscle tissue is metabolically "expensive" and not really necessary for survival. Your body isn't going to do it (save a few limited circumstances), unless it has a surplus of energy available. Consider this chart by Lyle McDonald

IronPlayground

Thanks for the info and the chart. Interesting that growth hormone is still up in underfeeding.

Chief_Rocka

Thanks for the info and the chart. Interesting that growth hormone is still up in underfeeding.

My guess is that it's because exercise-induced GH release will happen regardless of caloric intake.