Asked 7th Oct, 2017

How does muscle volume increase?

Muscle volume can increase for some reasons. What exactly happens when the muscle volume increases?Does the number of the muscle fibers increase or their volume?

Most recent answer

14th Jan, 2021
Kuzey Turk
Skeletal muscles are made up of a large number of muscle fibers. Satellite cells are skeletal muscle-specific stem cells located between the sarcolemma and the endomysium. Satellite cells become active when muscles are damaged due to exercise and form myoblasts, the cells that will proliferate and form the muscle fiber. Myoblasts form myotubes by first proliferation, then differentiation and fusion. Thus, the myotubes formed provide the formation of new fibers or the growth and development of muscle fibers by combining with existing muscle fibers.

All Answers (7)

9th Oct, 2017
Gordon L Warren
Georgia State University
Under most physiological perturbations, muscle volume increases because of increases in muscle fiber volume. Muscle fiber number usually does not change. Fiber number may increase somewhat following extreme overloading, at least in animals.
Deleted profile
Muscle fiber increase in volume through larger myofilaments, or connective tissue that enlarges. However, volume can also change through sarcoplasmatic hypertrophy. This is not directly strength related, because the contractile elements don't enlarge. The sarcoplasmatic volume is related to certain fluids. For instance creatine will hold more water in the muscle, so that is an increase in volume of the muscle fiber. In case of muscle volume, seen as outside the muscle fiber, there can be more blood vessels, that can contain more blood, and might increase the volume. Another optinion might be increase of fat storage inside the muscle. However, it is also depended on what you see as "volume" or muscle volume. If it is lean mass, or fat free mass it would be different.
4th Feb, 2018
Thomas McCullough
Lone Star College System
I am very interested in the concept of myofibril and sarcoplasmic hypertrophy. I know there are two researchers here that have shown some evidence that sarcoplasmic hypertrophy may exists. There is also a 3rd theory that another of our members espouses and that is hyperplasia. I have observed in my time around bodybuilders and powerlifters that there is a generally completely different training protocols and the visual aspects of both athletes are completely different. High volume, 8-12 reps seem to create a much fuller muscle, while low volume 1-5 rep training seem to create a much denser muscle, I am excited to see some work has been done in discovering how this happens and looking forward to seeing more. I can tell you that the most dense/muscular man I have ever seen was Ronnie Coleman. I sat and talked with he and his trainer for a little while a few years back. Ronnie trains like both a powerlifter and a bodybuilder. Could account for the tremendous size and density of his muscle.
Deleted profile
Thomas. The problem with sarcoplasmic hypertrophy is that it has to do with fluids and concentration. For instance, more creatine inside the muscle would attract more water, so there will be a volume increase. When for instance more enzyms or other molecules will be added I don't know if this will mean a change of volume. [water in, water out, electrolytes in and out]
That is why sometimes athletes have problems with volume and muscle, hardness and softness during competition. The management of electrolytes can alter water inside the muscle, but it is very debatable [and dangerous].
For instance, you can take creatine, CHO and drink a lot of water, to add muscle volume=sarcoplasmatic hypertrophy, but at the same time the muscle will get "bloated" or big but not defined. You want water out of the skin, and really into the muscle fibers. This is hard to achieve.
Normally 1-5 would train type IIX MF, but also to some extend the neural system. There will be more neural synchronization, increase in rate coding, it is not just muscle itself that get trained. A lot of mechanical stress also. With 6-12, there is less neural, and besides mechanical damage (less intenstive but more extensive, more time under tension), there is also more chemical stress, from substrates that are used to give energy.
In case of 1-5, you see powerlifters or weight lifters, also want low body weight because of competition element. Bodybuilders really focus on volume, in stead of strength (allthough they are really strong also). So 1-5 would store more energy for fast action, while 6-12, stores more energy substrates such as glycogen.
Best is of course to mix 1-5 and 6-12, because normally you have a wide variery of MF, so both is best to use.
When I found articles I will post them, I am interested also in the subject.
Regards Peter

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