Consider what it truly means to sit before we delve into the story of Homo Sedens. This thought-provoking sculpture in Aarhus challenges our notions of rest and posture. It is designed by the artist Jan Balling.
Homo Sedens. The Seated Man. It invites contemplation on the act of sitting itself. This isn’t just a statue. It is an artistic statement questioning our modern sedentary lifestyles.
AC Mandal was a leading Danish surgeon. He became disillusioned with conventional chair design. Mandal transferred his scientific training to the biomechanics of sitting. He observed children naturally tilt chairs forward. They support their elbows on the table. This maintains correct lumbar lordosis. As children grow, the table lowers relatively. Children sit in a slumped position. This results in backache and possible spinal instability.
Drawing on research, Mandal concluded children instinctively modify seats. They tilt forward with a slope of 10 to 20 degrees. This opens the hip angle and rotates the pelvis forward. The lowest lumbar joints are extended. This ensures correct posture. No backrest is necessary and the torso is free to move. Mandal proposed height-adjustable desks and forward-tilted seats. This is similar to an equestrian seat.
The recommended correct position was fundamentally wrong. Mandal suggests this posture developed from sitting a standing skeleton on a chair. A skeleton has advantages over a live human. It can sit motionless all day. It has no constraining muscles. It is steadied with an iron bar.
There is an increase in spinal loading. The pelvis tends to tilt backward. The position may be prolonged. Lumbar support accentuates this effect. Hip flexion also tilts the pelvis backward. The lower lumbar joints are forced into a flexed position. Mandal claimed 90% of lower back pain relates to loss of lumbar lordosis. Wrongly, the upright seated posture is taken.
Homo Sedens reminds us of Mandal’s work. Google shows many diagrams of correct seating. Some are actually correct. One diagram spells out arguably adverse ergonomic recommendations. The body position shown is cramped. Movement is hardly possible. There is no armrest. Some authorities maintain this allows greater torso movement. However, support prevents dropping of the shoulder girdle. Support at the wrists helps prevent RSI.
Unsupported cervical flexion results in much greater axial compression. A greater viewing distance allows the intrinsic eye muscles to relax. A semi-partial remediation incorporates pelvic support. Applying support directly to the pelvic crest ensures it cannot rotate backward.
Many comfortable office chairs have a fundamental bio-mechanical fault. They rely on the mid-upright mode of sitting. As shown, this combines adverse effects. The backward pelvic tilt can be modified by lumbar support. The latest version of BS EN states fixed-height desks should be 740mm. Desks should adjust between 650mm and 850mm for sitting modes.
So next time you sit. Think about Homo Sedens. Consider your posture. Think about the wisdom of children and the science of sitting. Let this sculpture be a constant reminder. The most natural posture is often the most healthful.