Muscle is a soft tissue in the body of humans and animals. Its main purpose is to produce force and motion.
Muscles are responsible for maintaining posture, physical movement (sitting, walking, eating, etc), and movement of internal organs (such as keeping the heart pumping to circulate blood and moving food through the digestive system).
The word muscle is derived from the Latin term musculus, meaning "little mouse". This Latin term could be due to the shape of some muscles or because muscles contracting under the skin can look like a mouse moving under a rug.
Tendons connect our soft contracting muscle to our hard bones.
There are around 650 skeletal muscles in the human body.
There are three types of muscle, skeletal, cardiac, and smooth.
Skeletal muscles (or striated) are voluntary muscles that control nearly every action a person intentionally performs. Tendons attach the muscle to two bones across a joint, as one muscle contracts the other relaxes which moves the bones.
Skeletal muscle can be further divided into two types, slow twitch and fast twitch.
Slow twitch (Type I) muscle contain proteins that give it a rich red color. This muscle carries more oxygen efficiently and using fats, proteins or carbs as energy slow twitch muscle fibers contract over a long period of time.
Therefore type I muscle fiber works well for aerobic sports such as long distance running and cycling.
Fast twitch (Type II) muscle is whiter in color as it has less myoglobin (a oxygen carrying protein). Fast twitch fibers contract quickly and powerfully, however they fatigue rapidly.
Therefore type II muscle fiber is useful for anaerobic exercise such as sprinting or for strength sports like weightlifting.
Smooth muscle (or visceral) is involuntary, its not controlled by our conscious mind. It is found on the walls of many organs and structures such as the esophagus, stomach, intestines, bladder, and blood vessels. Smooth muscles contract to move substances such as food through the organ.
Cardiac muscle is also an involuntary muscle. It is only found in the heart and is responsible for keeping the heart pumping.
Muscle makes up around half of the total human body weight. Muscle tissue is also around 15% denser than fat tissue.
It takes 17 muscles in the face for us to smile and 43 muscles to frown.
If muscle strength is regarded as the ability to use force on something then the jaw muscle (masseter) is the strongest in the body.
The strongest muscles in relation to the job they have to do is the external muscles of the eye which are large and about 100 times stronger than they need to be in relation to the small size and weight of the eyeball.
The tongue has 8 muscles, so is technically not the strongest muscle in the body.
The heart cardiac muscle does the most work of any muscle over a lifetime.
Cerebral palsy is a disorder that affects balance and motor functions, while muscular dystrophy is a genetic disease that damages muscle fibers.
Muscle memory is created by practising an action over and over again. Our muscles fine tune themselves, becoming more precise and exact in what they do. So practice is very important when learning a sport!!