At birth we are given a miraculous and amazing body to serve us through this lifetime. Unfortunately, it does not come with an owner's manual and frequently we do not understand how and why our body works the way it does. However, if we look at environmental survival adaptation theory, the functioning of our bodies can be understood.
Genetically encoded for survival
Let us go back many thousands of years to mankind's hunter-gatherer days. The leading cause of death was starvation. Refrigeration, preservatives and large food storage capacity were not available to early man. Therefore, in order to survive, the body had to develop a highly efficient fat storage capability. This enabled man to carry his excess food with him on his body in the form of fat. In addition, the body had to have a way to access this fat and turn it into energy, so that the individual could do things necessary to maintain life.
Man needed muscle to engage in life-sustaining activities like hunting, gathering, fighting, running, jumping, and climbing. To survive times of shortage man needed fat. The proportion of fat to muscle depended on his activity level. The dilemma - the more muscle he possessed, the quicker he burned through his fat storage; the less muscle, the more difficulty he had coping with the demands of life.
Our bodies reasoned that muscle is the most expensive cellular structure to maintain, thus, no more would be built than was required. All excess nutrition would be stored in the form of fat.
Slow and fast twitch muscle fibers
The process by which a body creates muscle is fairly straightforward. If you pick a berry from a bush, your brain sends an electrical impulse to the slow twitch muscle fibers of your hand and arm, causing your muscles to contract, thereby, pulling on your ligaments which are attached to the bones of your arm and hand - voila, you pick the berry! The entire activity is so organized and controlled that it seems to occur automatically. The slow twitch muscle fiber wasn't very strong. It was easy to use, and it recovered quickly.
Now let us pretend that you wish to pull large weeds from the ground. Your mind sends the message to your body, and slow twitch muscle fibers are activated. However, they are not strong enough to do the work, so more muscle fibers are recruited and now faster twitching muscle fibers are enlisted because they are much stronger. You strain and pull until enough faster twitching muscle fibers are recruited to pull up the weed. These faster twitch muscle fibers will require more time and rest to recover.
Now let's make believe that a 400 pound tree falls on your foot. Immediately, your brain sends the message to your very fastest fast twitch muscles to lift the tree. With extreme intensity, lasting no more than a few seconds, you lift the tree from your foot. It will take at least a week for your fast twitch muscles to recover from this exertion.
Catabolic, anabolic, and metabolic efficiency
All muscle building is basically a two-part process consisting of a catabolic phase followed by an anabolic phase. In the catabolic phase there is a stimulus which causes muscle fibers to contract. In the anabolic phase the muscles recover from that contraction.
The body will build the minimum amount of muscle required. In the berry picking scenario, because the muscle fibers recover very quickly, no new muscle is required, so none is built. However, pulling those weeds was quite a strain; and therefore, the body builds more muscle in order for this feat to be performed more efficiently in the future. In the “tree falling on your foot scenario" almost all available fast twitch muscle fibers were used, as a result, the body gets busy building more of the strongest muscle fiber that you have. This is a big job; it will take proper nutrients and at least a week of rest. It should be noted that if you begin another catabolic (breakdown) cycle before the recovery (anabolic) and rebuilding occurs, the fibers will be too depleted to rebuild, and muscle will be lost.
In conclusion, the berry picking activity could have taken hours with little to no muscle rebuilding. The weed pulling might have taken minutes, and a moderate amount of new muscle fibers may have been built. In the tree scenario, the activity lasted only a few seconds, but if sufficient recovery time and adequate nutrition is added to the formula, optimal amounts of muscle will be built.
Sources:
Charles Darwin, Origin of the Species, New York, Gramercy Books, 1979
Doug McGuff, M.D., John Little, Body by Science, New York, McGraw Hill, 2009
Lance Morton - Lance Morton is a writer, hypnotists, personal fitness trainer, and the author of Mentally Create your Ideal Weight.
