Originally Posted by
william_morris217
I think where this thread got misguided is the disconnect between theory and application. Is it possible to increase strength without increasing body mass? Yes, it is. But, is this adaptation something that can be appreciably programmed? Probably not. There are lots of things in the human body that are possible, so the argument that it CAN'T happen, may not be completely true, however, I believe Rip has already predigested this topic with a healthy dose of reality.
The generally accepted theories of increased strength are 1) increased cross sectional area of the muscle, 2) improved neuromuscular efficiency (timely recruitment of a necessary size and quantity of motor units), and 3) increased number of sarcomeres in series.
The literature is fairly clear that the neuromuscular efficiency piece happens immediately upon the beginning of a training program. The human body is capable of adapting to new stresses remarkably easy. The extent of which this improvement is measured is largely dependent on the person's genetics and the body part that is being forced to adapt to a stress. To the best of my knowledge, this improvement happens extremely rapidly, and further improvements take an extremely long time. I know of no textbook, research study, or anything else for that matter that states this adaptation occurs in an appreciable amount after the initial rapid improvements. If someone knows of such literature, please pass it along.
The addition of sarcomeres in series is another adaptation that occurs very slowly. Most of our knowledge of sarcomeres in series comes from case studies in which atrophied muscles are biopsied and it is found that they have a much lower number of sarcomeres in series, so the parallel is made that the converse would also happen....you stress the muscle and it must add sarcomeres in order to accomodate the stress.
That leaves us with an increase in cross sectional area, which is generally considered to occur through hypertrophy or hyperplasia. Granted, not many experts out there still buy into the hyperplasia theory, but it is still found in the literature from time to time. Compared to the other two mechanisms, hypertrophy occurs more readily than adding sarcomeres (theoretically) and begins to occur almost immediately upon the implementation of an adaptive stress.
The muscle tissue is damaged through training, there is an inflammatory response to repair the damage, and according to the myonuclear domain theory, skeletal satellite (stem) cells donate their nucleus to the adjacent muscle fiber and then the basement membrane dissolves, and the satellite cell blends into the muscle fiber. As a result, the number of nuclei increase, and the cross sectional area increases. Since muscle satellite cells are inhibited by contact with other satellite cells, so when this satellite cell blends with the muscle fiber, adjacent satellite cells divide to replace the lost satellite cell.
So the debate really is, what leads to the greatest increases in strength? If we argue this question, almost nobody can argue against hypertrophy. Are the other adaptations possible...yes, but does it make sense to rely on such adaptations when their overall effect is far less than what can be gained through hypertrophy?
TMPHBITEU
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