But is protein enough for strength training? Not exactly. Although protein is indeed very important, the role of glycogen in strength training is often not paid much attention.
This article will introduce the role and importance of glycogen in strength training.
What is glycogen?
Glycogen is the storage form of carbohydrates in the body. It consists of 8 to 12 glucose molecules, and then these glucose molecular chains combine to form large particles with more than 50 thousand glucose molecules.
These glycogen particles are stored in muscles and liver cells together with water and potassium until they need to be broken down and used for energy supply. Glycogen particles look like this:
The colored ribbon coil in the center of the picture above represents a special form of protein, which is the connection point of all glycogen chains.
Glycogen particles will increase with more and more glycogen chains attached to the periphery of the nucleus, and will also shrink with the decomposition of glycogen chains and the utilization of energy.
What is glycogen synthesis?
Glycogen synthesis indicates the production and storage of new glycogen particles.
In order to understand how and why glycogen is produced, we need to understand how the body digests and stores carbohydrates.
After eating, your body will break down protein, carbohydrates and fats into smaller molecules. Protein is broken down into amino acids, fats into triglycerides and carbohydrates into glucose.
The body can convert protein and fat into glucose, but the efficiency of this process is very low, and it will only produce enough to meet the basic functions of the body, which is far from enough to provide energy for strength training. This process will only accelerate when the glycogen level is very low, which is why you need to consume carbohydrates to produce a lot of glucose.
At any time, the body can only store about 4g of glucose in the blood. If the level is too high, too much glucose will damage nerves, blood vessels and other tissues.
In order to prevent this from happening, the body will use several mechanisms to deal with glucose so that it will not be injected into the blood in large quantities.
One of the most important methods is to package it into glycogen particles and then store it safely in muscles and liver cells. This process is glycogen synthesis.
Then, if the body needs extra energy later, it can convert these glycogen particles back into glucose and use it as fuel.
Where is glycogen stored?
Glycogen is mainly stored in muscle and liver cells, but a few are stored in brain, heart, fat and kidney.
Specifically, glycogen is stored in the liquid in the cell, which is called cytosol.
Cytosol is a transparent liquid composed of water, vitamins, minerals and other substances, which endow cells with structure, store nutrients and help support chemical reactions in cells.
Glycogen will float around after being stored in cytosol until it is decomposed into glucose, and then it is absorbed by mitochondria to gain energy.
This is what glycogen looks like under a microscope:
Most people can store about 100g glycogen in their liver and about 500g glycogen in their muscles. People with more muscle mass and training experience store more glycogen than this.
Your body will use glycogen stored in the liver as a direct source of energy, provide energy for your brain, and complete other body functions in one day.
But muscle glycogen is often used in exercise. For example, when you are doing squats, glycogen stored in quadriceps femoris, hamstring, gluteus maximus and calf will be broken down into glucose to provide energy for squats.