by Stuart McRobert Iron Man Magazine
Q: If I double my strength in all my exercises, will I double my muscle mass?
A: Probably not. Your question reminds me of something that Arthur Jones wrote, accompanied by photos of the flexed arms of his son, Gary, of average genetics, and longtime professional Boyer Coe, of freaky genetics. Arthur noted that while the strength of a muscle is related to its cross section, “it does not follow that increasing the cross section of a muscle by 100 percent will produce an equal [percentage] increase in strength. A larger muscle will be stronger than it was when smaller, but you might have to increase the muscle’s size by more than 200 percent in order to increase the strength by 100 percent.”
Arm girth is made up of more than muscle tissue, but an increase in the girth of your arms of “just” a few inches due purely to muscle growth produces a dramatic improvement in appearance. For example, the difference between a 15-inch arm and a muscular 17-incher is considerable, and the difference between a 15-incher and a 19-incher is enormous.
Gary’s arm measured 14 3/8 inches cold, and Boyer’s measured 18 7/16 inches. While Boyer’s arm was about 28 percent larger than Gary’s in circumference, the width of Boyer’s was 43 percent larger. The total cross section of Boyer’s arm was almost exactly twice as large as Gary’s, but the muscular cross section of Boyer’s arm was three times as large as Gary’s. While Gary could barbell-curl 120 pounds in good form at the time, there was no way Boyer could curl three times that.
When you compare strength in a given exercise over a period of time, you must use the same style of performance for the same number of reps. If your best effort now in the bench press is 175 pounds for six reps, to double your strength you’d have to be able to bench-press 350 pounds for six reps in identical exercise form and rep speed. (When you’re initially adapting to a new exercise, there’s more than just muscular strength involved. There’s a skill factor, at least to begin with.)
The relationship between strength increase and muscle size increase varies among individuals and is affected by the type of training performed.