what features of muscle contraction can be determined from an emg (electromyogram)
electric potential generated
title: Electromyography text: Electromyography Electromyography (EMG) is an electrodiagnostic medicine technique for evaluating and recording the electrical activity produced by skeletal muscles. EMG is performed using an instrument called an electromyograph to produce a record called an electromyogram. An electromyograph detects the electric potential generated by muscle cells when these cells are electrically or neurologically activated. The signals can be analyzed to detect medical abnormalities, activation level, or recruitment order, or to analyze the biomechanics of human or animal movement. EMG testing has a variety of clinical and biomedical applications. EMG is used as a diagnostics tool for identifying neuromuscular diseases, or as title: Polysomnography text: (the cornea is positively charged relative to the retina). This helps to determine when REM sleep occurs, of which rapid eye movements are characteristic, and also essentially aids in determining when sleep occurs. The electromyogram (EMG) typically uses four electrodes to measure muscle tension in the body as well as to monitor for an excessive amount of leg movements during sleep (which may be indicative of periodic limb movement disorder, PLMD). Two leads are placed on the chin with one above the jawline and one below. This, like the EOG, helps determine when sleep occurs as well as REM sleep. title: Electromyography text: muscles controlling bowel and bladder function. One basic function of EMG is to see how well a muscle can be activated. The most common way that can be determined is by performing a maximal voluntary contraction (MVC) of the muscle that is being tested. Muscle force, which is measured mechanically, typically correlates highly with measures of EMG activation of muscle. Most commonly this is assessed with surface electrodes, but it should be recognized that these typically only record from muscle fibers in close approximation to the surface. Several analytical methods for determining muscle activation are commonly used depending on the title: Electrophysiological techniques for clinical diagnosis text: as brain electrical activity mapping or BEAM ) The heart is the muscle that pumps oxygenated blood to the whole body. As a very active muscle, it has peculiar electrical activity that can be measured and analyzed. Electrocardiography is the measurement of these signals. Electromyography is the measurement and analysis of the electrical activity in skeletal muscles. This technique is useful for diagnosing the health of the muscle tissue and the nerves that control them. EMG measures action potentials, called Motor Unit Action Potentials (MUAPs), created during muscle contraction. A few common uses are determining whether a muscle is active title: Electromyography text: normal circumstances, very spontaneously active). When the muscle is voluntarily contracted, action potentials begin to appear. As the strength of the muscle contraction is increased, more and more muscle fibers produce action potentials. When the muscle is fully contracted, there should appear a disorderly group of action potentials of varying rates and amplitudes (a complete recruitment and interference pattern). EMG findings vary with the type of disorder, the duration of the problem, the age of the patient, the degree to which the patient can be cooperative, the type of needle electrode used to study the patient, and sampling error in