The exciting aspect to this idea is something that I have suspected all along - that the limit to human physical performance is not in the mechanical/physiological processes of the body,but in the nervous system and the mind.
Well.... I'm not exactly sure my father would have agreed with that. Remember, though, that he was a physiologist.
He was one of the first to show the clear difference between fast- and slow-twitch muscle fibers. He developed the chemical tests still used to identify them. He identified the sub-classes of fiber types. He also did extensive research showing that it is not possible to change a muscle fiber's type. In fact, his research combined with those of several others show that it is not possible to change a fiber's type by diet, training, environment, or drugs. While the human genome hasn't been decoded enough to know for sure, experts in the field today believe that your fast/slow-twitch makeup is genetically defined. This means that there are people who, no matter how they train, diet, medicate themselves, whatever, will never run a marathon. Some of those people might have been Olympic sprinters had they not fixed their goal on the marathon.
Dad also showed that muscle fibers do not split or replicate or otherwise increase in number in response to training. This research I remember well. Tables and tables of graduate slaves... I mean students, of course... hunched for hours and hours over microscopes dissecting muscles to the individual fiber so that they could count the number of fibers exactly. They first established that symetric skeletal muscles have the same number of fibers. Uninjured, your left bicep has the same number of fibers as your right. They did this first in rats, by the way, and later in chickens. (It's since been confirmed in humans too.) Next, they exercised the animals such that they only exercised one side, left or right. They did this to the point of getting a dramatic increase in muscle size and mass. But when they then removed both the left and the right muscle and dissected each to the individual fiber and counted the fibers, what they found was the exact same number of fibers in each side. No new fibers were created as a result of exercise.
Another common myth is that of "microtears." This holds that when you exercise, your muscles are sore because you tore some of the fibers and that the two torn ends will then heal and develope into two new, separate, and functional fibers. Not true. Experimentally disproven.
What this tells us is that the number of fibers in your body is also not something you can change with diet, exercise, or drugs. Again, the theory is that it's genetically-determined.
So, the conclusion of all of this is that your unchangable, genetically-determined body does limit your athletic potential.
For many years, WSU had an outstanding track team in the area of distance running. The stars came from Kenya. And the brightest of them all was Henry Rono. He would come and run on the big treadmill in Dad's lab for hours while reading his textbooks (pre-law as I recall, something quite weighty anyway). The running was absolutely nothing to him. He could study while running. Then, he'd gather up his things and head down for track practice. Dad did biopsies on him and typed his muscles and determined that all of the skeletal muscle in his body was 100% one fiber type, the exact perfect type for distance runners. This was not the result of any diet or training or drugs. He was born this way. He was also a very pleasant man, by the way.
