Because SEMG signals are small, their measurement is susceptible to interference – for example, from electrical equipment, lights or movement of cables that carry signals from the body to the measuring instrument. Evaluations require the subject to perform a full range of movement exercises and interference from movement of lead wires has been a problem.
Lower cost instruments attempt to eliminate artifact by electrode site pre-amplification and by “notching out” or filtering the frequencies at which interference occurs. Unfortunately, these frequencies are also where most SEMG signals are located. Devices that use “notch-filtering” lose essential data. That is why accurate, reliable SEMG measurement was impossible – until Noraxon.
Noraxon’s breakthrough amplifier technology actually distinguishes between SEMG signals and artifact. The result is reliable, repeatable and pure SEMG data that enables professionals to make more precise evaluations of muscle activity and performance. This is the secret behind all Noraxon systems.