What is Muscle Physiology?
There are 3 different kinds of muscle in the human body; Skeletal, Cardiac, and Smooth muscle.
Skeltal muscles are usually attached to bone on each end. They are connected by connective tissue tendons. When skeletal muscles contract, it causes tension on its tendons and attached bones. Muscle tension then causes movement of the bones at the joint where one of the attached bones movies more than the other. The moveable attachment is called the insertion and it is plled toward its less moveable attachment called the origin. There is something called the agonist muscle (primer mover). For an example, during flexion of the elbow, the bicep would be considered the agonist muscle. Flexors and extensors that act on the same joint but produce opposite actions are called antagonistic muscles.


Cardiac muscles are also called "heart muscles" or "myocardial cells". These muscles make up the wall of the heart. Cardiac muscles contract on their own to pump our blood. They contain actin and myosin filaments arranged in a form of sacromeres and they contract by the "sliding filament mechanism". The myocardial cells are tubular shaped. Unlike skeletal muscles, cardiac muscles are able to produce action potentials automatically.
Smooth Muscle is arranged in circular layers in the walls of blood vessels and air passages in the lungs. They are incharge of the contraction of hollow organs. The speed of smooth muscle contraction is only a small fraction of a skeletal muscle. Smooth muscles are much smaller than skeletal muscles. They are primarily under the control of the autonomic nervous system.

How does Muscle Physiology apply to Occupational Therapy?

There are many areas in Occupational Therapy where muscle physiology would come into effect. When we first see a patient, we would test their Range of Motion to see how much mobility they have. The way we test Range of Motion is asking them to perform Shoulder Flexion/Extension, Shoulder Abduction/Adduction, Shoulder Horizontal Abduction/Adduction, Elbow Flexion/Extension, Wrist Flexion/Extention, Wrist Ulnar and Radial Deviation, Digit Flexion/Extension. If we notice that our patient cannot move within normal range, we will try passive range of motion to see if their muscle allow further movement. If we have no gain on passive ROM, they have met total range of motion. After ROM has been tested, we will perform Manual Muscle Testing. This is a test that consists of having patient move their arm into elbow flexion, while we are pressing it into extension. We test this on all of the movements and actions described above. When we get results from the tests, we would then make a treatment plan and begin treatment sessions.

Sources: http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/M/Muscles.html http://www.uic.edu/classes/phyb/phyb516/smoothmuscleu3.htm