Maximize Muscle Growth With Precise Timing of Supplementation

I have always been aware that there is a link between Insulin and muscle growth. But for those of us who are not scientists, it's hard to get a simple explanation. The following are excerpts from 2 articles found here:
http://www.ast-ss.com/research/cribb/insulin_and_muscle_growth.htm
http://www.ast-ss.com/research/cribb/precision_supplement_timing4.htm

I encourage you to visit that site if you want the full text.

Maximize Muscle Growth With Precise
Timing of Supplementation. - Part 4

By Paul Cribb B.H.Sci.HMS. Exercise Physiologist


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Research now demonstrates skeletal muscle is not some inert reservoir from which the building blocks of protein and enzymes are obtained. Skeletal muscle is dynamic, it is the central organ that actively collaborates and participates in all amino acid transport and exchange with other tissues throughout the body. This occurs via two amino acid "pools" in skeletal muscle, one bound in muscle proteins and the much smaller "free-form" amino acid pool.

However, the body views these two reservoirs as one single homogenous pool as they are constantly interacting. Large amounts of amino acids move through this small pool each day, although the size of this pool never alters. This is because it is the initial supply of amino acids that meet all metabolic demands. The impact of exercise draws enormous amounts of amino acids from this free pool to the active site (exercised muscle). However, as the size of the small free pool is never altered, it’s constant, continuous replenishment occurs via breakdown of the larger pool, muscle! This is the reason muscle is extremely difficult to build and why many do not achieve the results they desire from their training.

Rebuilding, replacing large amounts of muscle protein is not a major, significant pathway of amino acid metabolism in adults. Human physiology is not concerned with depositing net muscle increases unless it absolutely has to. To make matters worse, these muscle-building pathways diminish a little with each passing decade. Therefore the small amounts of amino acids in this free pool govern all metabolic influences within the body, the degree of their metabolism dictates how much muscle tissue is catabolised (broken down) or maintained throughout life.

Major and rapid changes occur in muscle amino acid pools during all exercise. It is now confirmed that muscle occupies a central place in the production of energy (ATP), especially during exercise. Not as a direct fuel competing with fatty acids, blood glucose and muscle glycogen, but as precursors for the synthesis of anaerobic and aerobic energy cycle intermediates.

The aerobic energy cycle is also known by many names. Many texts refer to it as the Krebs cycle, TCA cycle or the Citric Acid Cycle, confusing I know, however they all mean the same thing! While the anaerobic and aerobic pathways represent opposite ends of the energy production spectrum, during exercise constant ATP (energy) regeneration is maintained via interplay of all energy pathways.

The view that all energy systems integrate to regenerate ATP levels no matter what the exercise is revolutionary. Most experts think they can keep use of different energy systems separated nicely when designing training protocols. However, this is not the case. An impact on one energy system has an impact on every other energy pathway, either directly or indirectly via utilization of its precursors - the material needed to power these systems.

Because of this tremendous impact, certain amino acids are metabolized in far greater amounts than previously suspected. It has been demonstrated that the branch chain amino acids (leucine, valine and isoluecine), glutamine and glutamate play vital roles as precursors to virtually all energy pathways. This aspect has previously been greatly underestimated. Unfortunately, this is real bad news if you are trying to build muscle. These are also the same amino acids that appear to be absolutely critical to muscle growth. Or more precisely, the amount of these particular amino acids retained in muscle appears to determine net muscle loss and gains. Research clearly demonstrates that most forms of exercise utilize these amino acids at such a phenomenal rate, little or nothing is left to affect mechanisms of muscle growth! In fact, there is research that demonstrates without supplementation of the precise materials of muscle growth, training on a regular diet produces muscle loss!

Putting Science on Your Side.

Large protein intakes not immediately required for cell anabolism (growth) are predominantly oxidized (burnt), used for other metabolic processes within the body.

If an external source of amino acids does not get there at precisely the right time, the result is an enormous drain on the small free amino acid pool and a subsequent breakdown of neighboring muscle proteins, all to keep replenishing the free pool and provide amino acids for the tremendously accelerated transport rates.

If an abundance of certain amino acids get to the active site directly after weight training, the result is a dramatic increase in muscle protein synthesis and turnover (the prerequisite mechanisms of building muscle) that produce net gains in muscle.

Directly after training is the critical window of opportunity to dramatically manipulate muscle growth. Although the size of the smaller free-form amino acid pool held inside muscle cells is tightly controlled, a wide range in amino acid concentrations still exist. Directly after intense or prolonged training, intracellular concentrations of most amino acids are at their lowest and the presence of high concentrations of amino acids outside the cell, in the form of supplementation (hyperaminoacidemia), are shown to dramatically accelerate rates of amino acid transport into the muscle cell.

Investigations conclude that the most important amino acids for building muscle actually have their own, exclusive cellular transport systems attached to the muscle cell membrane. There is a lot of "room" for manipulation to stimulate these transporters to accelerate their uptake rates! Simply by increasing substrate (amino acid) availability to the muscle cell at the precise time can stimulate or turbo charge amino acid transport systems to drive amino acids into muscle cells to the upper limits of physiological concentrations.

Accelerated inward transport of amino acids is shown to switch muscle anabolism mechanisms on! Accelerated inward amino acid transport directly stimulates significant increases in protein synthesis. The higher physiological concentrations of amino acids inside the cell also dramatically stimulate protein synthesis rates. Increasing leucine and glutamine content within muscle stimulates protein synthesis profoundly. These factors combined, trigger dramatic increases in muscle cell volume (water content). This is the most potent muscle building mechanism there is! Increasing cell volume ensures a positive nitrogen balance and net muscle protein deposition.