Muscle Types, Groups and Functions
Did you know that you have over 700 muscles in your body, and that these muscles make up nearly half of your body weight? The muscular system serves an important role, as it is what is responsible of the movement of the body and it helps to maintain the body’s posture. Most of the muscles are controlled through the nervous system, while some are completely autonomous. We take a deeper look into the muscular system, and reveal several types of muscles and what they are used for.
Types of Muscle
There are three main types of muscle: involuntary muscles, voluntary muscles and cardiac muscles. Involuntary muscles cannot be controlled and they work the internal organs. Voluntary muscles are the ones that can be controlled, and they are used to make the body move. The cardiac muscle is unique to the heart, and unlike other muscles, it never tires.
Voluntary muscles can have several different types of movement, including:
Flexion: An inward movement towards the body
Extension: An outward movement away from the body
Adduction: Movement of the muscle towards the body
Abduction: Movement of the muscle away from the body
Lateral rotation: The muscle turns outwards
Medial rotation: The muscle turns inwards
Some muscles come in pairs, whereby one muscle will relax and the other will contract in order to cause the muscle movement. Antagonistic pairs include the quadriceps and the hamstrings, the biceps and the triceps, the trapezius and the latissimus dorsi.
Active and Passive Stretching
Active stretching is the term given to muscles that are antagonistic pairs. Active stretching requires dynamic movement. Therefore, passive stretching is the opposite, whereby the stretching relies mainly on gravity. Active stretching is by far more powerful for those who want to stretch and strengthen the muscles in the body.
Origin and Insertion of Muscles
The origin of a muscle refers to the very end of a muscle where it is attached on to a fixed bone. The insertion of a muscle is the place that it is attached on to a bone that moves. For example, the hamstrings insert at the fibula and originate at the ischium.
Muscles in the Shoulders and Upper Arms
Major muscles in this part of the body include the trapezius, the latissimus dorsi, deltoids, rhomboids, triceps and biceps. The main function of the trapezius is to elevate the shoulder girdle, to rotate the scapula and to support the weight of the arms. The triceps are designed to straighten the elbow, while the biceps flex the elbow.
The abdominal muscles are responsible for flexing the trunk. The three main types of abdominal muscles are the rectus abdominus, the obliques and the transverse abdominus.
Pelvic Girdle and Lower Limbs
Muscles located in this area of the body are broken down into several different groups: hip flexors, hip abductors, hip adductors, external rotators, quadriceps, and the hamstrings.
As the name suggest, hip flexors enable flexing of the hip. They include the psoas major and the iliacus. The hip adductors are made to flex and abduct the hip, as well as extend and externally rotate the femur. They include the TFL, gluteus maximus, and the gluteus minimus. Quadriceps are what enable you to flex the hip and extend the knee. The hamstrings include the biceps femoris, semitendinosus, semimembranosus and the gastrocnemius.
It takes half as long to gain muscle as to lose it
The smallest muscle is in the inner ear
Taking just one step requires the use of 200 muscles
It takes 17 muscles to smile
It takes 43 muscles to frown!
When working out, it is essential that you practice safe stretching to prevent damage to any of the muscle groups. Regular gentle stretching helps to improve balance and strengthen the muscles, providing that it is done in the right way. Always gently warm up the muscles before undertaking any form of stretching. You should avoid jolting movements and fast repetitions, and instead aim for a gentle stretch that is held between 10 and 30 seconds. Stretching should never be painful, instead you should feel a mild discomfort and expansion of the muscles. If it’s painful, you are stretching too hard and can cause damage to your muscles. Another thing to consider is the breath, many people hold of restrict their breathing while stretching. This should be avoided at all costs, and instead normal or deep breathing will help you to move deeper into the stretch. After a stretching session, is is advisable to also have a cool-down session to release and relax your muscles. Things like yoga and tai chi provide excellent gentle stretching for muscles. Sports massages are also a great way to help release knotted muscles and improve muscle function.
If you have any from of muscle injury, then it is advised you seek professional medical help before continuing with any sports or stretching routine.