Back discomfort is attributed to a variety of causes. One of the most common is incorrect posture, including undesirable posture while sitting on a sofa. Many sofa styles are not designed to accommodate correct back posture. Instead, most sofas that are categorised as "comfy" sofas are detrimental to support of the back. Ergonomically designed sofas are constructed in such a way to support the body, creating proper back posture and minimising back discomfort associated with incorrect posture.
In the ideal back posture the supported spine takes on an S-shaped curvature. The weight of the torso goes through the lower spine, keeping it in balance. The tailbone is more upright and pressure is minimised on the lumbar discs. A slumped, C-shaped posture puts undue stress on the back, often creating backaches. This incorrect posture holds the body in a state of excess tension during the time spent slouching on a sofa.
Ergonomically engineered sofas are constructed to accommodate comfort and proper back posture. Lumbar supports built into the sofa support the lower back. Extra firmness added to seat cushions provides necessary back support that prohibits the body from sinking down into a slumping, incorrect posture. Feet should rest comfortably flat on the floor while the buttocks are scooted to the back of the sofa seat. Some ergonomic sofas designed with optional, adjustable headrests provide additional support.
Often replacing an existing traditional sofa with an ergonomic one is not economically feasible. Back lumbar supports, orthopaedic pillows and ergonomic seating supports are items that may assist with correct sitting posture on a traditional sofa. Each supportive product targets a specific body part, such as taking pressure off of the lumbar discs, massaging the lower back and reducing sedentary muscle contraction. Back belts worn around the body's midsection provide continual lumbar support.
In addition to facilitating chronic back pain, poor sitting posture contributes to reduced energy levels, poor circulation and weak muscles. Re-educating the body to become accustomed to a proper sitting posture may reduce back pain, contribute to easier breathing and strengthen internal muscles. Bad backs are relatively uncommon in third world countries where "comfy" sofas are nonexistent and correct, natural posture is forced daily, according to Dr. Mark J. Shaw, noted author and physician.