The term muscle comes from the Latin “musculus” meaning "little mouse" and refers to the soft tissue found in our bodies. Muscle cells contain protein strands that slide past one another to create contractions to change their length and shape. This causes force and motion to be produced, which allows us to move.  Every human body has more than 600 voluntary muscles, 20 of them in the hand. Oddly, there are very few in our fingers, as most finger movement comes from contracting forearm muscles connected to tendons. Without muscles, our basic motor and movement functions would be lost.

How do Muscles Work?

Muscle is tissue composed of threads of cells that contract and relax to create movement. These cells create motion energy from chemical reactions. Muscles that control joints work in tandem with other muscles to allow us the ability to move. For example, tricep muscles, which are located on the back of your upper arm, tighten and pull to straighten out your arm. In contrast, bicep muscles on the front of your arm tighten and pull to bend your arm. The biggest muscle in the human body is the gluteus maximus, or our butts. It is quite large because it is responsible for our back upright and swinging our legs to move.

Muscles(127184)Credit: Wikimedia

Why do we get Stiff Muscles?

Ever had that sore, stiff feeling in your muscles after waking up after a day of heavy activity or exercise? Or have you ever wondered why you are in pain after you go for a jog when you haven’t been running in a long time? Why is it that your legs ache so much?

This type of pain is known as Delayed Onset Muscle Soreness and arises when we engage in excessive exercise that our body isn’t used to. Previously doctors and scientists believed that the pain was caused from a build-up of lactic acid in the muscles, but now it is believed that the stiff muscle problem is attributed to microscopic trauma or damage to the muscle fibres during the exercise. The pain is the body healing that trauma. The good news is the pain normally only lasts a day or two after the exercise and diminishes.  As you continue to exercise, your body and your muscles will adapt quickly, so the next time you exercise you will get a little or no pain afterwards.

More Muscle Facts

  • Every day the six muscles that hold each eye move about 100,000 times.
  • We are born with all the muscles we will ever have. Once damaged, they cannot be replaced.
  • Our thigh contains the Sartorius muscle, of which its cells can be 25 centimetres (9 inches) long – the longest in the body.
  • A person could create a force of 23 tonnes if all the muscles pulled in the one direction.
  • The heart muscle beats about 69 times a minute. This equals 4166 beat in an hour, or roughly about 100,000 beats a day.
  • Relative to size, one of the strongest muscles in the human body is the tongue.

If you are interested in finding out more interesting facts about the human body, you can continue learning about eyes or hair.