Variability in vastus lateralis fiber type distribution, fiber size, and myonuclear content along and between the legs

This study provides a comprehensive analysis of the variability of key human skeletal muscle fiber characteristics in multiple sites along and between the musculus vastus lateralis of healthy and active individuals. We found a notable but nonsystematic variability in fiber type and size, whereas myonuclear content was distinctively less variable, and the prevalence of type IIX fibers was random and very low. These data are important to consider when designing and interpreting studies including musculus vastus lateralis biopsies.