I have said many times we all have the same number of fibres in a given muscle. Muscles are composed of thousands of fibres which do not multiply. They only thicken by exercise (induced capillaries). So what makes the muscle stronger?
Strength is the simultaneous contraction of muscle fibres. Exercise trains the muscle to simultaneously contract more muscle fibres in a given effort. If a muscle is flabby and untrained as little as ten percent of the muscle fibres contract simultaneously.
Whereas ninety percent of the muscle fibres contract (coordinate) in a trained muscle. This is why a muscle gets stronger from routine workouts.
Also, as I have stated many times, the number of capillaries multiply, and this is what makes a muscle larger.
As I have said before, a muscle continually exercises until it is depleted of sugar (fuel) tends to store more when it refuels at the next meal. This is why I recommend aminos and liver tabs every three hours.
Genetic superiors simply have more ability to coordinate muscle fibres than the rest of us. However, do not dismay this ability can be developed by anyone.
(IronMan, March 1984)