Muscle Growth Part I: Why, And How, Does A Muscle Grow And Get Stronger?

[Admin]

In concept, weight training is a very simple practice. You lift weights, you wait a while, you do it again. You improve over time and eventually you are stronger and bigger than you were before. When you strip it down it's really quite simple isn't it? The problem is things don't always go as smoothly as the above description would imply.
The Size And Strength Relationship

In bodybuilding circles there is the common misconception that muscle mass increases and strength increases are not necessarily related. That is to say, that you can increase the size of a muscle without it getting stronger. This mistaken belief presents itself commonly in the old "Bodybuilders aren't as strong as Powerlifters" argument. If strength was related to muscle mass, wouldn't Powerlifters be bigger than Bodybuilders? The explanation is simple: Strong people usually have better mechanical advantages than weaker people. This includes more favorable joint lengths and connective tissue factors (including attachment placings and superior tendon and ligament strength). They may have more type II fibers than others and/or a more efficient nervous system (which can be trained for). A muscle can be trained to get stronger but not bigger - this depends on rep range, training voulme and frequency. However, if a muscle gets larger it must also get stronger in the rep range over which it was trained. Likewise, if a muscle gets stronger in a rep range conducive to producing growth then the muscle will also get larger. It is a scientifically verified physiological fact that muscle size and strength are directly related.
Let's take a look at what happens to a muscle when you train it. Taking a segment from the Neuromuscular System series on the 'Physiology Related Articles' page:

• "Muscle biopsies of experienced bodybuilders have shown that it was the size of the individual fibers within their muscles that was responsible for the abnormal muscle size and not the actual number of fibers present."

Although there is some evidence that extreme conditions may re


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[Admin]

Muscle Growth Part II: Why, And How, Does A Muscle Grow And Get Stronger?



In Part I of this series it was explained that sarcoplasmic hypertrophy produces only moderate increases in muscle size. It was also mentioned that there are were other important reasons why such adaptations are desirable. In this section we'll take a look at those reasons.
Metabolic processes within the cell require ATP to "fuel" them (ATP is the body's primary fuel source for all of its energy). If enough ATP isn't present then a host of cellular processes slow down (including protein synthesis), resulting in the operations of the cell being compromised. This means, among other things, slower removal of waste products, slower recovery from training and slower or less protein synthesis. Research done in the former Soviet Union by Zalessky and Burkhanov has shown that if the contractile components of the cell continue to grow (sarcomere hypertrophy) without a concurrent increase in the energy supplying systems of the cell (i.e. mitochondria, etc. - sarcoplasmic hypertrophy) then such a situation will develop. Essentially, the contractile machinery of the cell has grown too large for the energy systems to support it. In addition, fellow Soviet researchers, Nikituk and Samoilov have demonstrated that such a condition can be brought about through poorly planned resistance training.
Once such a situation is created, the full potential strength of the muscle cannot be exerted because the cell cannot produce and utilize enough momentary ATP to cycle actin-myosin cross-bridges sufficiently. Likewise, when hypertrophy and strengthening is stimulated, growth cannot be supported because the cell lacks the energy systems necessary to support the synthesis and maintenance of new proteins (muscle protein is constantly being broken down and rebuilt - a process of 'maintenance'). In Bodybuilder's terms, you hit a plateau. Because such a condition is unproductive from an adaptative standpoint, it is called irrational hypertrophy. The defining characteristic of this kind of growth is cells that contain significantly larger mitochondria than in the untrained state, but fewer of them per myofibril. The net result is an ATP shortage in the cell.
On the other hand, if training results in proportionate vascular improvements within the cell (mitochondrial density increases - the total number of mitochondria also increases as the existing mitochondria get bigger), such a plateau will not be encountered and training-invoked hypertrophy can proceed. This is called rational hypertrophy, for obvious reasons.


http://www.weightrainer.net/training/growth2.html

 

[Goosey]

Interesting and covered quite extensively in the 70's and overlooked.

And opinion varies, but I've always believed the strength of a muscle must first increase in size before anything is even possible.

But measuring strength of a muscle is tricky, showing strength is simple, but many other factors are involved in this, as stated.