SURFACE ELECTROMYOGRAPHY (EMG)

A Surface EMG is similar to a "EKG" for the heart. By placing surface electrodes over the muscles to detecting and quantifying abnormal muscle activity measured in microvolts. A muscle contraction involves stimulation of a group of nerve fibers and EMG has shown a correlation with neurological reflexes that occur with injury. The number of fibers controlled by the nerve correlates highly with the function of the muscle: large muscle fiber to nerve ratios are found in muscles controlling gross movement, while smaller muscle fiber to motor neuron ratios are found in muscle groups responsible for finer movements, as in the hand.

MOVEMENT ANALYSIS

Modern human movement analysis is the interpretation of computerized data that documents an individual body part's motion during movement. In the past 25 years, the development of equipment, such as dynamic EMG, force plates, pedobarographs, electrogoniometers, and metabolic analyzers have made a more complicated, but also more complete acquisition of human movement available. Hundreds of laboratories around the world are now working on movement analysis. These laboratories primarily work with patients with neurological, neuromuscular, and orthopedic disorders of locomotion. However, there is also important work being done in analyzing sports-related movement.

MOVEMENT & EMG ANALYSIS IN INJURIES

Ergonomics researchers use EMG in validating the potential of certain input devices such as keyboard and mice for causing Carpal Tunnel Syndrome. Another area of great interest is the measurement of muscles during movement and isolated isometric contractions to assist in nerve to muscle re-education, disability evaluation, movement disorders and soft tissue injury. For example; in low back pain syndromes the Flexion-Relaxation Response utilizing the attached electrode dynamic technique of measurement has been evaluated thoroughly.

If problems are long standing, abnormal muscle fatigue will be displayed in the graph. If problems are more recent, it will show up as abnormally strong, or in spasm. Usually when a muscle has spasms it is to protect a weakened joint and/or nerve due to the laxity (stretching) that occurs with damaged ligaments that hold the joint in place. Ligaments are somewhat elastic like a rubber band. If you stretch a rubber band too far you either break it or lose some of its ability to return to the same taughtness. In your body, the brain notices this loss of elasticity and the instability to the surrounding joints, by creating muscle spasm to support and protect these injured and loose areas. These abnormal patterns in muscle activity can cause nerve irritation in the spine. This technology quickly obtain an objective picture of muscle activity and allows you to:

• Produce reports showing details in a format that is useful as a baseline monitoring tool for patient progress in their rehabiliation. 
• Demonstrate muscle imbalance & dysfunction. 
• Assess areas of muscles compared to normative data in areas of hyperactivity.

MOVEMENT AND EMG ANALYSIS IN SPORTS

DOCTORS, TRAINERS AND CONDITIONING COACHES rely on movement analysis as a tool to enhance techniques, correct movement errors, assess metabolic costs related to a variety of movements, and aid in rehabilitation. Sports performance is directly linked to human motion and performance so movement analysis is automatically a part of human performance assessment and analysis.

Today in many sports, sports scientists use biomechanical research of human motion respects the human body as a mechanical system of moving segments upon which muscular, gravitational, inertial, and reaction forces are applied. Modern computerized systems of movement analysis generally consist of placing markers on the subject that will transmit informative data from their position in space to receiver device(s) or force platforms that then assess those forces and moments related to gravity.