title: The Balans chair and its semi-kneeling position: an ergonomic comparison with the conventional sitting position.
abstract: Recently, the Balans chair has been introduced with claims that, because of its semi-kneeling position, individuals will experience decreased low-back pain (LBP) as well as improvement in circulation. This study investigated the validity of these claims. Twenty healthy subjects were randomly assigned to one of two groups. Group 1 subjects sat in the Balans chair for a 30-minute study period and then sat in a conventional office chair for an additional 30-minute period. Group 2 subjects were studied in the reverse seating order. Parameters studied were cervical and lumbar paraspinous surface EMG, and pedal cutaneous blood flow measured by laser-Doppler flowimetry. In addition, a questionnaire comparing the comfort of the two chairs was completed at the end of the study session. Comfort ratings showed an overall preference for the conventional chair. Increased cervical (P = .004) and lumbar muscle EMG measurements were noted after sitting in the Balans chair. Pedal cutaneous blood flow was increased by 15% in the Balans chair (P = .001). The data do not support the manufacturer's claim that the Balans chair is likely to decrease complaints of LBP.
mesh_terms: D000328:Adult; D001416:Back Pain / Q000517:prevention & control; D001775:Blood Circulation; D006804:Ergonomics; D005160:Facility Design and Construction; D005260:Female; D006801:Humans; D007374:Interior Design and Furnishings; D008159:Lumbar Vertebrae; D008297:Male; D008875:Middle Aged; D011187:Posture