Intra-day, short- and long-term reliability of surface electromyographic measurements during a standardized measurement protocol for lower back pain patients.

Background: The identification of back muscle dysfunction is a prerequisite for successful rehabilitation. Therefore, surface electromyography can be used for diagnostic and evaluative purposes. However, data quality highly depends on a) variance and inaccuracies in methodological procedures and b) on time-dependent changes, particularly in complex conditions such as chronic low back pain.