In response to resistance training, muscles typically increase in size.
One of the most commonly accepted and supported ways that this occurs is via an increase in the size of their individual muscle fibers. This whole process is called muscle hypertrophy.
However, another plausible way muscle could increase in size is through something called muscle hyperplasia.
Muscle hyperplasia refers to an increase in the number of muscles fibers within a muscle.
In the fitness world, sarcoplasmic hypertrophy seems to be quite controversial.
However, as we saw in a previous article (and as we’ll review in a moment), sarcoplasmic hypertrophy does indeed seem to be real, there are studies supporting the existence of it.
As we’ve explored in a previous article, it seems one of the primary ways muscles seem to grow is via an increase in the cross-sectional area of their muscle fibers.
There are 3 underlying ways a muscle fiber can increase in cross-sectional area: myofibrillar hypertrophy, sarcoplasmic hypertrophy, and myofibrillar packing.