Article: Proper ergonomic chairs will offer full upper and middle back support.  If you are going to be sitting for a long period of time, supporting your back and its natural shape will be important in preventing injury or strain.  Make sure your ergonomic chair has excellent upper and middle back support before making a purchase.  The backrest should be between 12” and 19” wide. Your chair's backrest should support the natural curve and shape of your back. Most backrests will be adjustable to support the contours of your back. Chairs without proper lumbar support will have a damaging and flattening effect on your lower back.  The lower back has a natural inward curve and poorly designed chairs will cause this curve to straighten out.  Make sure your chair helps you maintain your lower back's normal curvature to help your back stay strong and healthy.  Lumbar support can be adjusted by raising or lowering the chair's back support pad. Chairs that have an unadjustable back won't be a good fit for everyone. Being able to recline or adjust the back of your chair will affect the amount of weight placed on your lower back.  If you are planning on being seated for a majority of the day, reclining can help relieve pressure on your spinal discs and lower back muscles.  Avoid buying an ergonomic chair that can't recline. Most chairs can be locked into the most comfortable reclined position you find. Back pressure is lowest between 110° and 130° of reclining. People with lower back injuries can benefit the most from reclining chairs.

What is a summary?
Check the chair for adequate upper and middle back support. Examine the chair's lumbar support. Make sure the backrest can be adjusted or reclined.