Hello everyone, it is good to have you here again. Today, I will be looking at exercise and our daily activities, and their effect on the bones and the muscles. I decided to write on this topic because of an interaction I had with a group of people trying to educate them on exercise, and its impact on the bones and the muscles. One of the people said that the bone was a non living material in the body and that is why it is very strong, and daily activities and exercise cannot affect the bone and its features. Another one said that exercise only works and improves the muscle and not the bones. Well, I didn't take me long to win them over since it was a constructive argument, but so you reading won't tell someone outside the same thing, I have decided to do this post.
When humans first went to space, it was noticed that the bone density of the astronauts that went on the mission had decreased, as a result of lack of exercise and gravitational factors, and NASA has written that astronauts that went into the MIR space station lost up to 20% of their bone, but they regain this mass (if not completely) when they returned to earth. With this, I am sure we have a simple fact checked, that the bone is a living tissue.
Well, the person who said the bone was non-living is wrong but if he had used the word inorganic, it would have sat well with me partially, because the bone is made up of both organic and inorganic materials. The bone is made up of 60% inorganic material, 30% organic material, and 10% water.
Bone is made up of two types of tissues, the Compact Tissue and the Spongy Tissue. You see, the part we always see that is strong and densed is the compact bone tissue, while the spongy tissue is the inner part of the bone. For those who haven't had the opportunity to take a look at a cadaver, you will get an idea from chewing the bone of a chicken. You see, that spongy part you see which looks like it is moving in haphazard manner. You see, those tiny bones you see, aren't moving in an haphazard manner, they follow a pattern, and I will get to that in a jiffy.
The tiny spongy bones in spongy tissue of the bone is known as Trabeculae which has an orientation designed according to how much stress and strain (tensile and compressive force) the bone undergoes. The bone inorganic part is made up of hydroxyapatite, it is the ceramic material that covers the bone, made up of calcium phosphate mineral [Ca10(PO4)6(OH)2], while the organic compound in the bone is known as Collagen.
Before I continue with the bone, let me quickly touch the muscle (skeletal muscle tissue). I emphasized on skeletal muscle tissue because there are three types of muscle tissues and the remaining two are the Cardiac muscle, and the smooth muscle. The skeletal muscles are made up of several muscle cells which are fiber like. They are attached by tendons to the skeleton, helping to move the bones when thy contract and retract. There are two types of muscle fibers, which are the slow twitch muscle fibers, and the fast twitch muscle fibers. The fast twitch muscle fibers, known as fast glycolytic fibers provide bigger forces but with little or short duration due to its lower capillary, and synthesis glycolysis to produce ATP. Slow twitch fibers, known as slow oxidative fibers require oxygen to breakdown carbohydrate and fats to produce ATP. They are able to hold for a longer period of time because of their ability to hold on to oxygen, which helps them being useful in less stressful exercises.
When performing less stressful excises, the fast twitch muscles are not engaged, but when performing powerful exercises, the fast twitch muscles are engaged. When the fast twitch motor units are engaged, the fast twitch muscle fibers are triggered and they undergo hypotrophy which makes them larger and the muscle cells are increased as well, helping the muscle to store additional glycogen which helps to create more ATP, helping it to adapt with whatever exercise was done in the past, that it couldn't perform.
Back to the bone. When you walk, and run, you create a compressing force to the bone, while the part opposite to the direction of the movement in the inside of the bone performs the tensile force, and when you do a pull-up, there is a pulling force on the bone. When we perform exercises, the outside bone performs a tensile force while the inner bone deals with a compressive force. It is important to know that while you exercise your muscles, the bone is also stimulated to with a compressive and tensile force. With this, exercise, helps to increase the bone density and strength but people who do not perform any exercise usually have lower bone density. With bone density, when there is an increase exercise, it stimulates the bone's Osteoblast, which is responsible for bone build up to increase, while in cases where there isn't any exercise or activities on the bone, the osteoclast which is responsible for destroying bone tissues, starts to function more (Just like the astronauts)
Similar to the muscles, the bones are living tissues and are affected by exercise. When you are exercising your body, it is good that you know that while you are trying to grow that skeletal muscle of yours, you are also making your bone density higher.