Studying human muscle fiber types is intricate and time-consuming due to invasive muscle biopsies and individual fiber analysis.

“take a muscle biopsy sample, that's hard enough, right? It's invasive, people have to volunteer. Sometimes it's a little painful, but you get your biopsy out. Now you have to separate these muscle fibers. So you literally have to individually identify whether muscle fibers are fast or slow, and then you separate them into pools, and you analyze the type ones and the type twos. Very intricate, time-consuming work.”