The C-shape is not good for the body because, in this position, the body’s centre of gravity is behind the sitting bones rather than over them, which is an unstable position as there is minimal weight bearing on the legs, resulting in significantly increased pressure on the lumbar discs, stretching the ligaments and muscles supporting the spine, and this position puts pressure on internal organs. This makes breathing and digestion harder, and even means that the heart has to work harder to pump blood around the body.
Furthermore, because your thighs are at a 90 degree angle to the upper body, the hamstrings - which are connected to the pelvis and the back of the knee - are stretched. This also causes the pelvis to rotate backwards, contributing to the negative effect that the flat seat is having on posture.
And that’s not all. When you sit on a flat seat, some important postural muscles become inactive, and they almost stop producing lipoprotein lipase, an enzyme that’s important for removing fat and cholesterol from the blood. Studies show that, when these muscles are relaxed, enzyme activity drops by 90 - 95%, leaving fat in the bloodstream. Within a couple of hours of sitting, levels of a certain healthy kind of cholesterol plummets by 20%.
So - conventional flat seats are clearly not good for the body. Yet, despite the abundance of medical and scientific evidence that shows the dangers of this conventional kind of seating7, we continue to use it. That’s because we’re educated to sit on such seats from an early age, so it becomes a habit. Of course, manufacturers of flat seats do their best to correct the tendency of their products to force the sitter into an unhealthy C-shape. That’s why they include backrests - it’s an attempt to support the spine, prop the body up, and keep it from falling off the seat. But this is too little, too late because the pelvis is already in the wrong position for proper spinal support.
The result of all this is that many experts suggest that, rather than sitting down to do your work, you should stand up so you can avoid the musculoskeletal problems caused by conventional sitting positions.9 When you’re standing, the pelvis is in a neutral position, and the postural muscles help to keep the spine in a natural “S” shape. But, of course, standing to work is not an option for most of us. What’s more, it has long been known that standing all day is not only more tiring, but it dramatically increases the risk of carotid atherosclerosis by a factor of nine to be precise. That’s because of the additional load that’s put on the circulatory system. It also increases the risk of varicose veins. Clearly, standing is not the solution to the problem.
There is a solution - a solution that replicates all the advantages of standing, and puts the spine in its natural S shape, without actually making you stand. It’s a seat that’s specially designed to work with, not against, the musculoskeletal system and keep your upper body in a balanced position. Put simply, it stops your body from slumping while you’re sitting. It’s called the Bambach Saddle Seat.