J.E. Sleeth, Managing Director, OPC
In our practice we only refer to and use evidence based standards. This ensures clients receive the best responses in terms of the science of ergonomics. As well because we do not represent any lines of equipment or furniture in our practice we only recommend the best types of furniture, accessories, tools and design in our day to day practice.
High back chairs are manufactured and sold as “ergonomic” – these designs are only ergonomic in the case where an employee has a bona fide neurological impairments such as MS where a lack of neck control has occurred and needs to be supported by the high back chair.
In otherwise healthy subjects the use of high back chairs cause the neck to be placed into a forward flexed posture thereby loading the anterior portion of the discs of the C Spine and causing static loads at the paraspinal muscles. These chairs are not recommended in these cases in our practice.
The use of kneeling chairs has been recommended only once in our practice and this was related to a specific nerve root related impairment in the lumbar spine. The reason these stools are not recommended is for two reasons –the angle of the seat pan results in the facet joints on both side of the lumbar and lower thoracic spine being compressed which eventually can result in compression injuries at the facet joints. 2. Placing the knees into a >90 degree flexed posture coupled with compression at the patella (knee cap) will load the patellar femoral joints of the knees and can eventually lead to compression type injuries to the soft tissue of this joint.
Again the bottom line goes to practical solutions – we tell all of our clients to always buy the best chairs on the market – spend money on the chair – and combine this with training for all employees on how to adjust their chairs; educate employees on the fact that no matter how great the chair they must stand and walk/stretch out of the chair at least every 45 minutes.