Muscle fibers: Do you choose slow endurance or strong fast?

Understanding fast or slow twitch muscle fibers will help you choose the right exercises to get in shape.

There are different types of muscle fibers in the body, classified based on how they produce energy. You can work these muscle groups by performing exercises that are specifically designed based on how muscle groups generate energy or generate force.

Muscle fibers are classified into two main groups:

• Slow-twitch: Also known as type I muscle group.
• Fast-twitch muscle group: Also known as type II muscle group.

Slow-twitch muscle fibers

Slow-twitch muscle fibers contain mitochondria, organelles that use oxygen to help make adenosine triphosphate (ATP). This process is known as aerobic metabolism. Slow-twitch muscle fibers are also known as red fibers, because they contain more myoglobin (oxygen storage) pigment with a darker appearance. This red color appears due to the presence of iron, which helps bring more oxygen to aerobic respiration.

Slow-twitch muscle fibers, also known as durable muscle groups, can provide their own energy source and maintain force for a long time. However, this muscle group cannot produce strong force, but only performs uniform and prolonged force. Therefore, these muscle fibers are often present in endurance runners.

Strength training exercises can help increase mitochondrial density, which improves the efficiency of how the body uses oxygen to produce ATP (Adenosine Triphosphate). Exercises to increase the size of slow-twitch muscle groups may include:

• Contraction exercises: These exercises still involve prolonged muscle contraction, but little or no joint movement to keep the slow-twitch muscle fibers active for a long time. This can help improve the ability to use oxygen for energy production. For example, plank exercises such as front plank, side plank or one-leg balance exercise.

• Repetition Exercises: These exercises are intended for resistance training with lighter weights than usual, but at a slower tempo of motion and a higher number of repetitions. Training with slow-twitch muscle groups helps stimulate aerobic metabolism to promote better muscle performance.

For example, normally you train your biceps with a 15kg dumbbell and repeat the movement 10 times (rep) in a set (set). For endurance training, you can do 10kg singles with more than 15 repetitions in a set.

• Circuit training: Means rotation training, this is a method of combining many movements with high intensity. Exercises that are performed continuously or only for short periods of time form a circle, a seamless sequence of exercises. During the training session, usually perform from 4 to 10 exercises, helping to effectively build slow-twitch muscle groups.

• Body-weight exercise: It is a method of exercise that does not require weights or complicated equipment, only using the body’s own weight to exercise. This exercise helps to stimulate metabolism and improve muscle group efficiency.

During exercise, you should pay attention to rest periods should be shorter than about 30 seconds between sets to stimulate slow-twitch muscle fibers to use aerobic metabolism to promote training.

Fast-twitch muscle fibers

Fast-twitch muscle fibers can be classified into:

• Type IIa: Glycolytic fast oxidizing, by using oxygen to help convert glycogen into ATP. This is an intermediate muscle fiber between I and II, using both aerobic and anaerobic processes for energy. This muscle fiber is gray.

• Type IIb: Fast, ATP-based Glycolytic that is stored in muscle cells for energy. This is a muscle fiber that represents strength and speed, using anaerobic processes to generate energy. This muscle fiber is white.

Large fast-twitch fibers only need a short period of time to reach their peak force and can produce more force than slow-twitch fibers. This muscle group can generate more force, but tire more quickly than slow-twitch fibers.

Performing strength training exercises can increase the number of fast-twitch muscle fibers, depending on the specific exercise. The characteristics of the fast-twitch muscle group are more suitable for explosive, powerful and strength-based sports such as football, sprinting, etc.

If you want to build more muscle fibers that contract faster to increase your strength level or become more explosive, here are some exercises you can refer to:

• Heavy training: Heavy weight exercises help stimulate motor units to activate more muscle groups. The heavier the weight, the greater the number of fast-twitch fibers that will be affected.

• Do “explosive” movements: These exercises can be understood that, when you perform a movement, there will be a combination of speed and power to the highest. For example, the jump jump, you sit in a squat position and use your heel force to push your body quickly and strongly.

Fast-twitch muscle fibers tire quickly, so focus on training heavy or “explosive” movements with only a limited number of repetitions, for example 2 to 6 reps. achieve maximum efficiency.

Because this workout depletes energy quickly, fast-twitch fibers require longer rest periods to recover and replace the used ATP. Therefore, you should rest for at least 60 to 90 seconds after each “explosive” or strengthening exercise.

Which muscle group should you train?

Most of the human body has an average ratio of two types of fast and slow twitch muscle fibers. Each person will build a different amount of muscle fiber depending on the training process and fitness goals.

For example, in endurance athletes such as marathon runners who can have up to 80% of muscle groups slow to withdraw, you can see that their thigh muscles are often lean and toned. Whereas sprinters can have up to 80% fast-twitch muscle fibers, the thigh muscle area is often large and muscular.

Currently, there are many schools of muscle training such as bodybuilding, fitness, physique, weightlifting, street workout …. The most popular schools are bodybuilding and fitness. To distinguish these two schools, you can easily see through the shape.

• Bodybuilding: For people who want to have strong muscles. Performing exercises will mainly build fast-twitch muscle fibers, because this muscle group has a stronger size growth rate.

• Fitness: For people who want to build aesthetic beauty, harmony and slimmer. Therefore, the performance of the exercise will mainly build the slow-twitch muscle fibers in a durable way.

No matter what muscle fiber you want to build, being proactive in exercising is always the biggest “plus” because this will help your health better. Therefore, make time to practice at least 30 minutes a day to achieve your desired fitness and health goals!

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