Muscle Fibers & A Flash Back To My Past

My dear brother who works in the same industry inspired this week’s blog. We both are strong willed, value good health and live to help others improve their health. Our training styles can be different and our nutritional advice may or may not match. But one things for sure, we are teachers to the people we work with and the people we work with are in turn our teachers. Long story short, he and I were having an interesting discussion about muscle fibers and exercise this past weekend. So this week’s topic is regarding muscle fibers (fast twitch and slow twitch) and how those muscle groups come into play.

Slow twitch muscle fibers have a high resistance to fatigue and a slow contraction time. Structurally these muscle fibers are small in diameter, contain small motor neurons, higher amount of triglycerides and a low amount of creatine phosphate. What this means is that these types of muscle fibers are at work when you participate in low impact aerobic activity such as walking, sitting (keeping posture) and life’s daily task. In addition, slow twitch muscle fibers use more fat for energy compared to fast twitch muscle fibers.

Fast twitch muscle fibers consist of fast twitch A & B. These muscle fibers are opposite of slow twitch. For example, they are larger in diameter, higher in creatine phosphate, glycogen and fair in triglyceride stores. These muscles come into play during a long duration of anaerobic activity with a high intensity output such as racing. Fast twitch B fibers are more likely to fatigue however, they contain more power than ST muscle fibers, which is why they work well during short anaerobic activity, like sprinting, jumping etc…

Athletes who excel in certain sports such as sprinting are likely to have more fast twitch B muscle fibers compared to endurance athletes who may have more slow twitch muscle fibers.

If your wondering which muscle fibers you may have more of, then ask yourself what am I good at? In other words, do you do excel in endurance sports such as running? If so, you genetically have more slow twitch muscle fibers. Maybe, you excel in sports such as power lifting. Then you genetically have more fast twitch muscle fibers. Can you change your genetic makeup, no. On the other hand, if you have more slower twitch muscle fibers and you want to get into power lifting, you can train your fast twitch muscle fibers resulting in an increase in strength but you will always have more ST and may not excel in power lifting like someone who genetically has more FT.

In closing I thought I would include some fond memories of growing up. I have always been a tomboy and perhaps that has to do with growing up with two brothers. I can remember always wanting to be like my older brother. We were inner city kids and grew-up in some rough areas. Weight training was a lifesaver for my brothers and I. It gave us confidence and self-esteem. I remember the first time my brother trained me. He basically put 100 lbs on the bench press and told me to, “get it up and don’t expect my help.” Somehow I got the impression that he wasn’t going to help me, so out of fear I benched pressed 100 lbs. As cruel as that may seem, that prepared me for many difficult situations that I later faced as a teenager. And to some degree that molded me to who I am today.

All of life’s experiences can make us, break us, shape us and through every experience we become better and our bettering is a gift that we can share with others.