Muscles represent about 20% of our total body mass. This percentage depends on genetics, sex, age.

Muscles are physiologically more developed in men than in women.

Our body is composed of 639 muscles. The smallest muscle of our body is the stapedian, it is located in the ear. The longest muscle is the sartorius, which is an internal muscle of the thigh. The strongest muscle is the gluteus maximus, and not the muscle of the tongue because the tongue is composed of 17 different muscles.

What are our muscles for?

The primary function of our muscles is the production of movements, but they can also, on the contrary, prevent movement. In addition, they serve to stabilize the joints.

Finally, their last function is to produce heat.

What is a muscle made of?

The muscle is composed of a muscular body and several tendons. It is composed of several muscle bundles inside which are many muscle fibers.

These muscle fibers are themselves composed of myofibrils which generally go from one end of the muscle fiber to the other.

Finally, a slice of myofibril is called sarcomere and is composed of actin and myosin filaments that have the property of contracting and relaxing. The sarcomere is the contractile unit of the muscle, which allows our muscle to contract and therefore produce movements.

 

How does muscle contraction work?

For a muscle fiber to contract, a neuron must transmit an electrical impulse that is an “action potential”.

The area where the neuron and the muscle fiber meet is called the neuromuscular junction. The electrical message sent by the neuron is transmitted, at this junction, to the muscle fiber.

This signal will extend all along the muscle fiber. This will trigger a contraction; each sarcomere will shorten thanks to the actin and myosin filaments that have this ability to contract and relax. The fibers, by contracting or relaxing, slip against each other and thus, move the muscle. This contraction requires a molecule of ATP to allow the myosin head to cling to the actin filaments. We are talking about the theory of sliding filaments.

What is an ache?

An ache is a muscle pain that occurs as a result of intense or unusual physical exercise. So, with time and the adaptation of your body to the effort, the aches will diminish and eventually disappear.

They cause microtrauma related to microlesions of the muscle tissue. Some metabolic waste created during exercise may intensify muscle soreness by infiltrating the muscle.

But contrary to what we usually believe, lactate produced during an effort and which, in large quantities, paralyzes the muscle, does not cause aches. As a matter of fact, lactate is eliminated after one hour as from the end of the exercise, so it cannot be the cause of muscle aches that appear at least 12 hours after physical exercise.

It is difficult to prevent aches, but the cryotherapy seems to be an effective solution to ease, it allows a recovery both better and faster.

Muscle and diet

Good nutrition is essential for proper muscle function and recovery.

It is therefore important to provide proteins for protein synthesis in order to maintain or increase our muscle mass.
But we must also provide carbohydrates for the resynthesis of glycogen stores and lipids for the proper functioning of our organism.

It is therefore necessary to bring these 3 macronutrients in balanced quantity after training but also in your daily diet to improve recovery and performance.

We must also think about vitamins and minerals that are involved in many mechanisms for the proper functioning of our body and especially our muscles. For example, calcium is essential for muscle contraction. Antioxidants limit the oxidative stress generated by physical exertion.

Poor nutrition increases the risk of injury. The study by Rosen et al. Shows that unbalanced diet (and lack of sleep) would increase the risk of injury in high-performance teenagers.

References:

Rosen, P., et al., 2017. Too little sleep and an unhealthy diet could increase the risk of sustaining a new injury in adolescent elite athletes. Scandinavian Journal of Medicine and Science in Sport.