In my last post I briefly outlined what hypertophy is, and explained that in order to maximize the benefits you get from such a training regimen, you need to design it so that it is tailored towards the nature of your sport. There a number of factors that go into this, and in this post, I’ll talk about muscle fiber and type.
There are two types of hypertrophy: sarcoplasmic and myofibrillar. The easiest way to picture these two is by labeling sarcoplasmic “bodybuilding” and myofibrillar “powerlifting/weightlifting”. Here’s why.
Sarcoplasmic hypertrophy is an increase in muscle cell fluid, called sarcoplasm, which accounts for about a quarter of the muscle’s size. But although the increase in fluid causes the muscle’s area to increase, the density of the muscle does NOT increase, meaning there is no increase in strength.
So if there’s a minimal increase in strength, why utilize this type of training? It may not make the muscles super strong, but it does make them bigger. Thus, bodybuilders use this type of training to bulk up, since they only have to look good, and not necessarily be strong.
How do you go about training like this? High reps, low volume. Generally, greater than 12 reps per set hits the Type I muscle fibers, which causes an increase in the non-contractile parts of the muscle. So if you’re an athlete, this is really not for you.
Myofibrillar hypertrophy is an enlargement of the type II muscle fibers and an increase in density of the contractile parts of the muscle (the part of the muscle that generates strength). There are two subdivisions of type II fibers: type IIA and type IIB. Type IIA fibers are generally utilized in muscular endurance, whereas type IIB fibers are the more powerful of the two.
Both of these types of fibers are important to athletes, but some moreso than others. Smaller athletes will tend to need more endurance fibers, as they have to work harder to keep up with the bigger, stronger athletes. Type IIB fibers are stressed with sets of 1 to 5 reps, and type IIA fibers are hit with sets of 6 to 12 reps.
So that pretty much covers it as far as muscle type goes. Next post I’ll delve into another component of functional hypertrophy. Until then, stay thirsty (for knowledge!) my friends.