Weight-lifting in a postural restraining device: a reliable method to generate paraspinal constant force contractions.

Epidemiological studies have shown correlations between muscular deficiencies (low endurance capacity) and low back pain. With the emergence of new electromyographic surface recording methodologies (power spectrum investigations), a renewed interest in the electromyographic signal during sustained muscular contractions can be observed. A technique is described which is acceptable to chronic low back pain patients and which creates comparable constant force contractions in normal controls and pain patients. This method has advantages over those procedures requiring maximum voluntary contractions by the patients.