Different types of Muscle Fibers and how to Train Them
Muscle fibers; without them we would be unable to lift, move or train. The fibers that make up our muscles are made up of several filaments all of which contain actin and myosin cross bridges, with the help of ATP these fibers allow our muscles to contract and relax. Over the course of this blog we will look into how different muscle fibers influence training, what certain fibers are capable of and how we can manipulate our training to target these specific fiber types.
Type 1 Fibers
Type 1 muscle fibers , are known as slow oxidative fibers. These fibers are primarily used for long distance endurance style work. Type 1 fibers do not fatigue quickly, they are able to go through a ton of low low intensity work before fatiguing which makes them a favorable fiber type for those who are looking to compete in endurance events. Type 1 fibers have extremely high mitochondrial density as well as high capillary density. Which allow them to utilize oxygen extremely efficiently. Most activities we engage in on a day to day basis utilize these fibers.
Type 2 Fibers
Type 2 muscle fibers, are known as fast glycolytic fibers. These fibers are primarily used for short intense work. These fibers are broken down into type IIa and type IIx fibers. Type IIx fibers are used for extremely short bursts of work which produce high force, power, and speed production. Type IIa fibers on the other hand are a blend between type 1 and type 2 fibers.
How To Train Certain Fiber Types
Most of our fiber type is determined by our genetics. Unfortunately for us we cannot train to fully change our fiber types. Most people have a 50-50 split between type 1 and type 2 fibers. Those of us that excel in endurance exercise usually have a fiber split of 60-40 where as those of us who excel in sports such as power-lifting, sprinting, and anything that is explosive in nature have a fast twitch fiber make up of around 60-40. Through training you cannot change type 1 fibers into type 2 fibers but you can change type 2a fibers into type 2x fibers. Aka you can train to become more explosive and powerful. Researchers at Harvard medical school have also found that when people increase their type 2a to type 2x ratio they have a decrease in fat mass.