Posture. Biological mechanics in action

The great artist, mechanic, and inventor of The Renaissance, Leonardo da Vinci, represented the body in the form of a mechanical device. We can say that he was the “Father of Biomechanics,” the science of mechanical movement of body parts. In the section of physics dedicated to movement (mechanics), such key notions as strength, supporting point, lever, and its arm are used.

If you don’t remember much about physical science, don’t worry. Remember something more pleasant instead, like swinging in the park. The board you sit on when you swing is the point of application of force; the place at which the board is swinging is the supporting point; the distance between you and the board is the lever arm, and the swing is the lever. The whole operates as a pendulum.

The most important moving parts in our bodies are our bones. Do you know how many bones your skeleton has? Strange as it may seem, a newborn child has nearly 300 bones and an adult has approximately 206 of them. The explanation for this phenomenon is quite simple: some bones become knit together as a person grows and becomes older. If you examine the skull of a newborn, you will see that it has tender spots between the bones of the skull. These are fontanels that disappear during the first year of a child’s life. These areas permit the baby’s skull bones to move during delivery. Another example is the intact hip bone of an adult. A child’s hip bone consists of separate parts: pubic, sciatic, and iliac that fuse as the child grows.

Hard bones form the skeleton with the help of ligaments and joints. It is well known that even hard metal can turn to powder because of rubbing or due to friction. This is also true of bones. Mechanics use lubricants like oil to preserve working mechanical parts. In our bodies, the role of lubrication is played by a smooth cartilage layer in the joints. Its width is only several millimeters, so it needs especially considerate care.

I describe joint and cartilage diseases and the ways to take care of these in my books, “ Smart Neck”, “Smart Back”, “Smart Loin”, “33 Vertebrae or I Love My Osteochondrosis”, “Rules of Spine Movements” and others.

If we keep counting the parts of the skeleton, we will start counting joints as well. There are more than 230 movable and semi-movable articulations, or joints, in our bodies. Some bones are connected by joints that are not fully movable. For instance, the pubic bones are joined by a symphysis. It is movable, but it makes no “moves,” as such. The number of moving joints in the skeleton is impressive! There are 27 of them just in one arm! 

If we evaluate a joint from the point of view of mechanics, then it is a movable pair that can be both a supporting point of a lever and a part of a pendulum. Joining bones together creates real mechanical chains. It is a well-known fact that if you pull on one end of a chain, then the other end has to move. Biomechanics looks at our body as a group of biomechanical chains, pendulums, and levers.

Summary

• From the point of view of biomechanics, the human body is a combination of pendulums and levers.
• In a biomechanical chain, a change in one part causes changes in the whole system.