[The following is a guest blog by Vanessa Williams. Vanessa is an Athletic Lab intern from ECU] There are three muscle types and every person has them in varying degrees. They are Slow Oxidative (SO), Fast Oxidative Glycolytic (FOG, and Fast Glycolytic (FG). The best way to determine your fiber type ratios are by muscle biopsy. This is an inconvenient and painful procedure though which most people don’t have access to. Here is some helpful information that will help give you a better understanding of the three muscle types and perhaps allow you to take a guess as to your own fiber type ratio:

  • The ratio of both types of muscle fiber varies in each individual and each muscle.
  • Ratio is thought to be genetically determined.
  • Both types of fibers can improve their metabolic capabilities through specific strength and endurance training.
  • Athletes like sprinters and weight lifters have a large percentage of fast-twitch fibers.
  • Endurance athletes like marathon runners generally have a higher percentage of slow twitch fibers.
  • Muscles that primarily maintain posture against gravity require more endurance and generally have a higher percentage of slow-twitch fibers.
  • Muscles that produce powerful, rapid, explosive strength movements tend to have a greater percentage of fast-twitch fibers.