L3__Introduction to muscle fiber types (skeletal muscle) and training methods

The human body has three major muscle types: skeletal muscle, myocardial muscle, and smooth muscle. Given that this chapter mainly discusses content related to athletic performance, we will focus on introducing content related to skeletal muscles.

This chapter mainly introduces the types of muscle fibers in skeletal muscle and the corresponding characteristics and training methods of muscle fibers.

About Skeletal muscles

Skeletal muscle, also known as voluntary muscle, is the only type of muscle that we can control through conscious control. Skeletal muscles are mainly used to generate strength and control movement. When we exercise, skeletal muscles generate strength through contraction and relaxation, enabling us to perform various movements.

Definition: Skeletal muscle is composed of muscle fibers that are connected to the bones through tendons, enabling us to exercise and maintain posture.

Structure: Skeletal muscle is composed of hundreds or even thousands of muscle fiber bundles, each of which is composed of many muscle fibers. Muscle fibers are the basic units of muscles, composed of myofibrils

 Type: According to the contraction speed and ability of muscle fibers, skeletal muscles can be divided into slow muscle fibers (Type I) and fast muscle fibers (Type II).

Training: In order to develop and enhance skeletal muscles, we can stimulate muscle growth and strength growth through different training methods. This includes strength training, weight training, high-intensity interval training (HIIT), and explosive exercise. In addition, a reasonable diet and rest are also crucial for muscle development.

I believe you have noticed after reading the previous text that in order to achieve different athletic performances, we need to train different muscle fibers.

First we need to know the characteristics of different muscle fibers.

Slow muscle fibers are rich in mitochondria and can continuously produce energy, making them suitable for endurance sports such as long-distance running, swimming, and aerobic exercise. Slow muscle fibers have a slower contraction rate, but can work continuously for a longer period of time, making them suitable for long-term low-intensity exercise. Stimulating and training slow muscle fibers can be achieved through long-term aerobic exercise such as jogging, swimming, and cycling.

Fast muscle fibers are divided into two types: fast muscle fiber type A (Type IIa) and fast muscle fiber type B (Type IIb or IIx). Fast muscle fiber type A has certain endurance and strength, suitable for moderate intensity exercise such as fast running and weightlifting.

Fast muscle fiber type B has high strength and explosiveness, but fatigue is fast, making it suitable for high-intensity, short-term explosive sports such as sprinting and jumping. Stimulating and training fast muscle fibers can be achieved through high-intensity strength training and explosive exercises such as weightlifting and sprinting training.

How do you train each type of muscle fiber?

For slow muscle fibers:

Aerobic exercise options: Choose the aerobic exercise that suits you, such as jogging, swimming, cycling, rowing, etc. These exercises require a longer duration to activate slow muscle fibers and improve endurance.

Heart rate control: By controlling the heart rate, ensure that training is conducted at an appropriate intensity. The goal is to maintain a heart rate between 60-70% of the maximum heart rate, which is the effective range for activating slow muscle fibers.

Time and intensity: Gradually increase the time and intensity of exercise. At the beginning, you can engage in 20-30 minutes of aerobic exercise, gradually increasing to 45-60 minutes. At the same time, gradually increase the intensity of exercise, such as increasing running speed or swimming strength.

Long term continuous exercise: Slow muscle fibers require prolonged stimulation to receive effective training. Try to maintain continuity in exercise and avoid excessive rest time.

For fast muscle fibers:

Weight training: Weight training is the main method of stimulating fast muscle fibers. Use heavier loads for training to promote muscle strength and volume growth. Choose compound movements with multiple joints, such as squats, bench presses, and hard pulls, which can activate multiple muscle groups and increase the participation of fast muscle fibers.

Number of groups and repetitions: Perform fewer repetitions, usually between 6-8 times. This ensures the use of sufficient load to stimulate fast muscle fibers. Each group consists of 2-4 groups, with appropriate rest time between them to ensure muscle recovery.

Explosive movements: Add some explosive movements to training, such as jumping, sprinting, and fast push-pull movements. These actions can increase the strength and speed of fast muscle fibers.

High Intensity Interval Training (HIIT): Using high-intensity interval training methods such as countdown training or loop training. By taking brief breaks after high-intensity work, fast muscle fibers can be activated and muscle strength and endurance can be improved.

Sources Cited:

• Sport Science Insider. "Muscle Fibers Explained: Type I and Type II (Slow & Fast Twitch)." Sport Science Insider, 2023, sportscienceinsider.com/muscle-fibers-explained-type-i-and-type-ii-slow-fast-twitch.

• OpenStax Anatomy & Physiology. "10.5 Types of Muscle Fibers." OpenStax, Oregon State University, 2023, open.oregonstate.education/aandp/chapter/types-of-muscle-fibers/.

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