Sunday, 06 September 2015 05:53

Muscle Movement

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Muscle Movement




Muscles are the cogs that drive the machine (machine being your body). They are instrumental in every activity you do from walking to running to frowning and smiling. Muscles are directly responsible for the shape of your body. Muscles protect the skeletal and organ systems and they hold the body's joints firmly in place so they can operate effectively. Without muscles, the body could not breath or digest food nor circulate blood around the body. Every movement, exertion whether voluntary or not occurs in the body through the work of muscles.


Every muscle, no matter where it is in the body operates through the basic principles of contraction and relaxation (Hitchcock, 2007). Some muscle actions occur on a voluntary basis where you are consciously aware. For example, reaching out and grasping a glass of water and lifting it to your lips requires the voluntary action of many muscles. On the other hand some muscle actions occur on an involuntary basis where you have no conscious control over them contracting and relaxing. An example of this occurs every time your heart pumps blood around your body.


watch video on skeletal muscles


Muscle Types


The muscular system comprises of three kinds of muscles which include:


  • Skeletal
  • Smooth
  • Cardiac


Skeletal muscles are the largest muscle type in the body and are responsible for moving the body. They can be controlled consciously and come in various shapes and sizes. Smooth muscles occur in organs and blood vessels and cannot be controlled voluntarily. Smooth muscles are essential for day to day survival performing essential function inside your body like conveying oxgen and other gases through the respiratory system so you can breath. Cardiac muscles occur in the heart and are directly responsible for the circulation of blood from the heart to all cells in the body.


Muscle Structure


Muscles are made up of many cells working together. When muscles contract some components within each fibre slide in on top of others shortening and tightening the fibre. On the other hand when a muscle relaxes these components release and seperate lengthening and loosening the fibres (Hitchcock, 2007).


The nervous system is responsible for muscles contracting and extending. Electrical signals travel from the brain to the spinal cord via nerves branching through the body to the muscles. When a muscle cell is stimulated by a nerve ending it reacts causing a series of interactions which allows that muscle to contract or relax resulting in movement. Deliberate movements of muscles involve thousands of communications between the brain and the nervous system into the muscle cells.


Fueling your Muscles


The muscular system requires adenosine triphosphate (ATP) to transform chemical energy into movement energy. Muscle cells only store small amounts of ATP so muscle cells are constantly refueling by aerobic respiration (with oxygen) or anaerobic respiration (without oxygen).


Aerobic respiration uses oxygen to breakdown glucose molecules which results in energy being generated. In anaerobic respiration, blood cells have to bring the necessary glucose to muscles cells which is less efficient for energy generation. Aerobic respiration is the usual method of ATP replenishment in muscles cells however if a person begins exercising more strenuously, anaerobic respiration kicks in.


Two types of Muscle Fibres


Every skeletal muscle in the body is made up of two types of muscle fibres known as fast-twitch and slow-twitch fibres. Fast-twitch fibres contract the muscles quickly whereas slow-twitch fibres contract the muscles slowly. The fast-twitch muscles are used in sudden rapid movements like jumping, sprinting or even blinking your eye. Slow-twitch fibres on the other hand can keep muscles working for a long period of time and occur in movements like running, rowing or swimming. 


Every single person has a combination of slow-twitch and fast-twitch muscle fibres. Some bodies however are genetically inclined towards one muscle type. When a trainer or coach advises a person to cross train their body they are essentially asking the person to train the muscle fibres that are less predominant in their body. For example a weight lifter may be advised to use a running machine to build up a combination of strong fast-twitch and slow-twitch muscle fibres.


Muscle Cramping


When a muscle contracts suddenly and involuntarily it is called a spasm. When a muscle spasm cuases pain it is referred to as a cramp. Cramps tend to occur during exercise or when a person is sleeping. At this stage their cause is unknown however the best response is massage and hydration to relieve the muscles affected.




Hitchcock et al. (2007) Body - The Complete Human: How it Grows, How it Works and How to keep it Healthy and Strong. National Geographic Society USA.



Read 3169 times Last modified on Sunday, 06 September 2015 07:13

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