By: Juan Rodriguez
Did you ever wonder why some people can last a long time while exercising? Or why high intensity exercisers have the power they need for their challenging exercises? Our body is composed of a variety muscle fibers that work differently based on the activity that is being performed.
Slow Twitch Muscle Fibers
Lets start with the slow twitch muscle fibers, also known as slow oxidative (SO) muscle fibers or type 1 muscle fibers. These fibers are highly used for endurance exercises and may provide up to hours of energy . Something to keep in mind is that these muscle fibers contact very slowly and cannot generate energy for fast performance. This means exercises that are mainly long in duration or high repetition in low weight-bearing exercises. Now you may wonder how people that run long periods of time are able to maintain that energy needed to keep going? Our bodies are composed of cells called Mitochondria that produce the energy needed by breaking down sugar, fat and other chemicals with the assistance of oxygen. The more an endurance athlete trains, the more Mitochondria they have and therefore, they may exercise for a longer time.
Fast Twitch Muscle Fibers
Fast twitch muscle fibers on the other hand are larger and more powerful muscles that work for less amount of time. These muscle fibers work primarily with creatine and sugar to produce the amount of energy needed for the exercise. Since these muscle fibers generate more power, they are found in individuals who perform high intensity and power exercises that require high amounts of energy and fast muscular contraction. Those activities may include sprinting, power lifting, and soccer for example. How long will the energy last with these muscle fibers? There are a few fast twitch muscle fibers that last different amounts of time, but depending on the amount of mitochondria (as mentioned above) each muscle fiber contains, the time may vary. However overall, the duration is about 30 seconds to 1 minute for a fast twitch muscle fiber. To sum it all up, if you are someone that performs more fast and high intensity power exercises, you will have a greater density of fast twitch muscle fibers. On the other hand, if you perform more endurance exercises, you will have a greater density of slow twitch muscle fibers and higher amounts of Mitochondria!
If you have any questions about this blog, feel free to comment below !
Julie is the program director and head personal trainer at Ageless Fitness. She focuses on wellness and health education with her clients and encourages the process of creating programs to be individual and informative