When people think of muscles, they tend to think of body builders with bulging muscles, but there is so much more to muscles than this. There are approximately 650 muscles in the body. Muscles are like ‘machines of the body’ that allow the body to produce movement, stabilise joints, maintain posture and to generate heat. The body comprises three types of muscle:
Skeletal – move the skeleton and produce movement voluntarily by stimulation of nerve impulses. Skeletal muscles are attached to the skeleton at either end by tendons and operate by using the bones as levers and the joints as points of movement.
Smooth – typically found in muscle walls of organs, such as the stomach, digestive and respiratory tracts and bladder, and produce movement involuntarily.
Cardiac – the heart is predominantly made up of cardiac muscle and produces movement involuntarily.
Energy for muscles
Adenosine triphosphate (ATP) is often described as the body’s ‘energy currency’ that transports chemical energy within cells for metabolism. ATP is used to power muscle contractions and as the muscles contract or shorten, the ATP molecules are broken down or hydrolysed to release energy. ATP is the only energy source that can directly power muscle activity within the first 10 seconds of exercise, after that time, ATP must be replenished quickly, so muscles begin to breakdown carbohydrates and fats to produce ATP for sustained energy.
Carbohydrate metabolism is far more efficient at producing energy quickly when compared to fat metabolism.
Glucose and stored carbohydrates in the form of glycogen in muscle cells are broken down through a series of steps to produce ATP. Glycogen is converted into glucose by muscle cells and when glycogen levels are depleted, there is a pronounced loss of energy and fatigue. L-Glutamine can also be metabolised by the pancreas, liver and kidneys to produce glucose through a series of chemical reactions. L-Glutamine is an important energy source for many tissues in the body.
Supporting muscle health after exercise
L-Glutamine helps to preserve muscle levels of glutamine after exercise. Physical and metabolic stress increases the body's utilisation and demand for L-Glutamine, consequently L-Glutamine may be beneficial during periods of increased physical stress.