How can you find out your ratio of fast and slow twitch muscle fibers?

Question

How can you find out your ratio of fast and slow twitch muscle fibers?

Answer 1

-I found this in an article and thought it might be able to help you out. The original areticle can be found at the link below. I hope this helps.

"Muscle fibers that respond quickly are called fast twitch muscles. The ones that respond more slowly are called slow twitch. Fast twitch muscles are used for explosive, high power motions, but fatigue easily. Fast twitch muscle is best suited for delivering rapid intense movements for short periods of time (e.g., jumps, and fast footwork).   Slow twitch muscles have slower reaction times and develop lesser tension than fast twitch but are more fatigue resistant and are important for activities which require high endurance.  (In a chicken, white meat is primarily fast twitch muscle, dark meat is primarily slow twitch!)

The average person has muscles with an even mix of fast and slow twitch muscle fibers. Endurance athletes such as long distance runners and marathon runners have a high percentage of slow twitch muscle, as much as 80% in marathon runners. Sprinters, football linebackers, and the like have a large percentage of fast twitch muscle, as much as 60 to 70%.  To a large extent the ratio of fast twitch to slow twitch muscle in a person is genetically determined. In track and field, it is said, great sprinters are born and not made. Recent studies, however, indicate that some muscle fibers can be trained to respond as either fast twitch or slow twitch muscle. Thus, through proper training, it appears the fast to slow twitch ratio can be altered to a limited extent. Skaters who are sluggish in their jumps and spins, and lack explosive power in their skating might consider taking this into account in developing their off-ice training.

Because a muscle twitch occurs so rapidly, less than 1/6 to 1/10 second, repeated stimulation of the motor groups is required to maintain muscle tension for extended periods of time. In order to provide a sustained exertion each motor group is fired by its motor neuron repeatedly. The frequency with which the motor group is fired is variable up to the point where the contraction of the motor group is continuously sustained. This condition can be maintained until muscle fatigue sets in (up to a few seconds for some muscles). In addition to repeatedly firing individual motor groups, muscles activity is controlled by the number of motor groups involved in the contraction.

We will spare you the details of the chemical and electrical reactions that take place in muscles when they contract, but one practical aspect of that which is important to athletic activity is worth mentioning.  The force developed by a muscle turns out to be related to its temperature. For a given stimulus, a muscle develops lower tension when its temperature is lower, and produces a higher tension when it is warmed up. The purpose of the warm-up period preceding athletic activity is not only to stretch and get limber, but also to increase the temperature of the muscles so they will produce greater forces during the subsequent athletic activity.  Skaters who warm up before their performance and then stand around in the cold shivering before they perform are penalizing themselves by making their muscles significantly less able to produce at the level they are capable of at the start of their program. Since most skaters put some of their most difficult jumps at the start of their programs, it is advantageous that muscles be fully warmed up at the start of the program.

During physical activity, most of the energy used by the muscles of the body goes into producing heat. Only 1/5 to 1/4 of the energy used in muscle contractions goes into actual work (i.e., jumping spinning, moving, etc.).   In addition to temperature, the force developed by a muscle is affected by its state prior to the contraction.  Specifically, a muscle that contracts from a pre-stretched condition will develop 5 to 10% greater force than a muscle that is contracted from its at rest condition. This characteristic of muscles appears in most forms of athletic activity in some form or another. In baseball, for example, the wind up prior to swinging a bat pre-stretches the muscles of the back used to actually swing the bat when the time comes. Similarly, stretching the arm back prior to throwing a ball increases the force with which the ball can be thrown. The greater the stretch, the greater the force that can be developed. "