Fast Twitch vs Slow Twitch Muscles

Judging from the title, it may come as a surprise to you since you might assume muscles are just muscles. It’s ironic if you consider training to come off as a broad term to you just like it would for me. An obvious reason can be attributed to the training itself. A powerlifter and a cyclist are going to have different goals in mind that starts with training which would make comparing them akin to apples and oranges. It goes the same way with a sprinter and a marathon runner which is why we can’t say one is better in shape than the other. We are really just comparing how well they train their muscle fibers.

Fast twitch muscle fibers are the muscles responsible for helping you move faster in shorter periods of time whereas slow twitch muscle fibers are responsible for keeping you moving longer although more slowly. One is focused on intensity whereas the other is focused on endurance. The “twitch” is the contraction, or how quickly and often the muscle moves. The slow-twitch muscles activate first which makes a lot more sense when you consider warm-ups before a workout and the likelihood that an athlete would injure themselves ignoring it. It’s only fitting that the slow twitch fibers are Type 1 where the fast twitch fibers are Type 2. Our fast-twitch fibers create energy without oxygen where our slow-twitch fibers have more blood vessels for more oxygen and longer use. That’s why when the topic of running or cycling comes up, there is an emphasis on pace. When I ran track in high school, my coach would always advise the team to stay on a man especially when it was windy. A lot of times in the long distance races, the person who started off in the lead could not manage the same pace, likely attributed to starting too fast. During outdoor track, it was often attributed to them absorbing the wind while the person pacing them from behind was conserving their energy to pass them towards the end. The slow twitch muscles can only go far when considering they use oxygen to generate energy in the form of ATP from their high concentration of mitochondria. For anyone needing a biology refresher, ATP is the principal molecule for storing and transferring energy in the cells. That being said, the slow twitch muscles will keep you going as long as you have enough oxygen. My Coach understood that in practical terms even if he is not the one to give us lessons on the methodology.

Why It Matters

During the last couple of weeks of my deployment to the Middle East, I was doing serious investigating trying to determine why I was not as ripped as I should be. After all, I got 80% down considering the nutrition and abs being made in the kitchen. It then hit me which merits a shout-out to my Lieutenant at the time if you are reading this being more knowledgeable on this. For as long as I can remember, my running has been predominantly long-distance. While I was over there, I did a 14-mile ruck mark and even ran the Marathon. As I have a proclivity for experimenting, I gave up long-distance running for the remainder of my time there, switching to sprints with my weight-lifting. It was not long before the vindication came up in the mirror. As I have noticed over the years, it seems like a common belief that losing weight geared toward fat loss is dependent on longer cardio which is usually low-intensity activities like walking, long-distance running, cycling, swimming, etc. As I used to share that notion, I wish it to be the case. With the phrase, “Work smarter not harder,” less means more and more means less. When you train in particular with lowering your body fat, the training needs to be intense. High-Intensity Interval Training (HIIT) workouts would be recommended as they target the fast twitch muscle fibers rather than the slow twitch muscle fibers leading to calories being burned before and after the workout. In simpler terms, a 15 minute HIIT workout or even 10 minutes of jump roping will burn more calories than an hour of walking! I think walking is still useful as I go for frequent walks as they are stress relieving, however for dropping body fat, you may want better tools at your disposal. Intense training like a HIIT workout will force your body to use and burn energy which will rely on fat even afterwards in which a handful of you will recognize as the afterburn effect. As the body’s demand for oxygen increases proportionally. During the workout, the body needs more oxygen than breathing could provide leading to an “oxygen debt” where the demand for oxygen exceeds the actual amount of oxygen delivered. As the body needs hours to recuperate on oxygen, more calories get burned and could last as long as 3 days! If you ask me, one of the most significant reasons people are obese and/or overweight is being either misinformed or uninformed. I blame the lack of clarity that’s not helped by overwhelming information that seems to contradict one another, an example being you will see an article telling you why you should not eat this and another advising you to eat more of it.

Something Else To Keep In Mind

As we get older, we are likely going to have to train differently. It will be more crucial to incorporate more strength training into our routines especially for women as they are more at risk of osteoporosis that directly affects bone density. Sarcopenia, muscle fiber loss, starts to happen after 30 where we can lose as much as 3 to 5 percent of muscle mass per decade. Sarcopenia can put us at greater risk for falls and fractures and can lead to limited mobility. It also greatly affects the fast twitch muscle fibers more than the slow twitch muscle fibers. The biggest cause of muscle loss is due to inactivity and as older people tend to either be sedentary or improperly, the loss in the slow twitch muscle fibers are amplified. That muscle loss can begin as early as around 25 which makes it more imperative to be active. Generally, muscle fiber loss is due to a loss in motor neurons which are the communication cells that send signals to the muscles to make them perform. As this results in the loss of nerve supply to the muscles, often referred to as denervation and it is followed by a process called apoptosis. It’s due to this that the fast twitch-muscle fibers start to receive nerve supply from different motor neurons, usually from slow twitch-muscle fibers, practically adopting their characteristics. It’s been found in studies through the data that a 60 year old has fewer motor neurons than a 20 year old by a percentage ranging from 25 to 50%. It’s one of those examples that serves as a reminder to keep training our muscles with emphasis on the fast twitch to slow down the denervation as the loss will increase the risks of injury and affect our body composition for the worse. This is why I remind my parents that relying solely on walks is not going to pay dividends since it’s all too common that people who go for walks are middle aged to old aged. The sooner we act the better because if there is one thing to know about the human body, it’s that everybody has their own deadline and we have to decide if we are going to lengthen it or shorten it!