Are you really sitting comfortably? A field study of a forward sloping chair and sedentary low back pain sufferers

Abstract

A number of authors have suggested that office chairs designed to encourage users to sit with an "open" trunk-thigh angle (approximately 110-120 degrees) will be more comfortable than conventional chairs and will have beneficial consequences for sedentary low back pain sufferers.
This assertion was investigated in a 4 month trial in which 35 sedentary workers were given a forward sloping chair to use. Ratings of perceived back pain and postural comfort when using the chair were compared with ratings obtained when conventional chairs were used. Additionally, users' comments on both chair types were obtained.
For the sample as a whole, significantly less lower back pain was reported on those occasions when the forward sloping chair was used. However, a number of participants reported no change or more back pain when using the forward sloping chair. Users’ comments on the chair highlighted a number of practical advantages and disadvantages which relate to its suitability for use in office settings.
Although the majority of users preferred the forward sloping chair to their usual chairs, the available data do not permit the differential response to the chair to be explained on either personal, occupational, anthropometric or ergonomic grounds. A more clinically orientated investigation would seem to be required.