💊Daily Pill: Fast Twitch Vs. Slow Twitch Muscle Fibers
Understanding Your Muscle Fiber Makeup
The Daily Pill is a series of very short daily posts where I share the definition of a medical term I think we should all know. Read it every morning and build up your medical vocabulary.
💪 Fast Twitch vs. Slow Twitch Muscle Fibers
Turn out muscle fibers are categorized into two main types: fast twitch and slow twitch. Fast twitch fibers (Type II) are designed for quick, explosive movements and generate more force but fatigue quickly: Sprinting, blinking, jumping, etc. Slow twitch fibers (Type I), on the other hand, are built for endurance and can sustain activity for longer periods without tiring. For example, your neck muscles - necessary for keeping your head up, or your diaphragm - which never stops moving.
Interestingly, every single muscle in your body contains a mix of both fast and slow twitch fibers, though the proportion can vary.
🤔Why you need to know:
You can actually modify the composition of your muscle groups by choosing specific exercise modalities. For instance, engaging in activities like sprinting or weightlifting can increase the proportion of fast twitch fibers, enhancing strength and power. Conversely, endurance activities such as long-distance running or cycling can increase slow twitch fibers, improving stamina and endurance. Tailoring your workouts to target these fibers can help you achieve your specific fitness goals.
This is one of the reasons why sometimes strengthening your back fixes lower back pain pain. As it was the case for me: If you have weak slow twitch muscle fibers - which are in charge of maintaining your posture, what happens is that your fast twitch muscles will have to pick up the slack… but that’s not what they are designed for! so they get tired, they strain and begin to hurt, and then they tense up and get inflamed. If you have lower back pain there is a chance that therapy and strengthening those back muscles may help - depending on what you specifically have, obviously. Talk to your doctor.
🧠Trivia:
Elite sprinters and marathon runners have vastly different muscle fiber compositions. Sprinters like Usain Bolt possess a higher percentage of fast twitch fibers, giving them the explosive power needed for short distances. Meanwhile, marathon runners like Eliud Kipchoge have a greater proportion of slow twitch fibers, enabling them to maintain a steady pace over long distances.