I have not been on the forum lately been crazy busy last few weks but I saw this post and thought I would add to it. My old trainer Scott Abel explains some of this in an article. I think it is good reading!
[SIZE=+2]Muscle Growth/Blood Volume
By Scott Abel[/SIZE]
People often ask me at gyms or at my seminars what is the real key to muscle growth. My answer often perplexes them. Most expect to hear some “opinion” over sets reps and workout frequency. But I am a man of science and my gains have come in large part to my knowledge base. In order to make real world gains it is imperative to have some understanding of the basic science of what is involved in growing massive muscles. Only the genetically gifted get by without any kind of knowledge base in the area of muscle and muscle development. I’m going to walk you through some important facts and information on the science of building muscle.
Without addressing the training side of the equation for now, my answer to the question, what is the key to building muscle growth is two fold. Simply put, the answer is blood volume and cell hydration. But one of these seldom occurs without the other. Nature’s responses to training stimuli not only give us the answers to how muscles grow, but nature also gives us hints on we can expound on nature to produce even more muscle growth. Before we can get into the nitty gritty of that science, lets back track a moment to review just what a muscle looks like and what structures it is composed of; and as I mentioned, this is scientific in nature but important for general and specific understanding of muscles, and muscle growth.
A muscle consists of several components important to understanding growth. The first two main factors of a muscle cell are the sarcoplasm and the myofibril components. The sarcoplasm consists of a nucleus of many proteins, enzymes and hormones, and also the mitochondria, also known as the ATP factory, where muscle energy is made and stored. The sarcoplasm is considered to be a bath of proteins within which is contained the rest of the components of the muscle cell. The other main component of the muscle cell is the myofibril component. Myofibrils house the fast twitch 2a and 2b fibers you’ve all read so much about. It is the myofibrillar component of a muscle cell we are most concerned with when looking at training and the muscle’s cells adaptation to training. The major contractile proteins of the myofibril are the actin and myosin proteins, which through an action called “cross bridging” slide across each other to produce contraction. However it is important to note also that there are more than a dozen other accessory proteins that exist to participate in muscle action. Ok, so now we know a little about the major players of the structure of a muscle cell, the sarcoplasm, and the sarcoplasmic reticulum, the mitochondria, the myofibril, and its main protein components, actin and myosin. Also surrounding any muscle cell is a proliferation of other cells known as satellite cells. Satellite cells exist to protect the cell in question. In times of trauma, like that of intense training, satellite cells respond quite specifically to the stimulus, and that is what produces muscle growth, or what is scientifically known as hypertrophy.
Hypertrophy
The most basic and clinical definition of muscle hypertrophy is, simply an increase in the individual cross section of a muscle fiber, either the sarcoplasm, or the myofibril, or both. As strength athletes concerned with understanding muscle growth our focus is mostly on the myofibril. But the whole scenario of hypertrophy is important to understand to really know what the process is in muscle growth. When we train intensely for muscle gain, something in the muscle cell occurs called myofibrillar splitting. This splitting creates a tiny whole in the muscle cell. Out of that whole leaks key proteins and amino acids, one known as hydroxyproline. When that happens a whole cascade of biochemical and endocrine activity occurs. I will cover the endocrine side of this in greater detail below, when discussing the “pump”. Hormones such as FGF (follicle growth factor), IGF1, and IGF2, also leak out of the cell. The IGF hormones send a direct message to the satellite cells, which as you recall surround the cell to protect it. The satellite cells then fuse with the myofibril creating a larger cell, with an increased cross section, and this is what is defined as hypertrophy, or muscle growth, as you would have it. Now you know exactly what is muscle growth, which is muscle cell hypertrophy and now you have a working understanding of how that process takes place. It always amazes me how many people confuse hypertrophy with other things like a pump (exercise induced hyperaemia) which I will get into below, or confuse hypertrophy with a term called protein synthesis. While all these items are correlated in the matter of muscle growth there are also entirely distinct functionally even though as we will see, one activity definitely has
