Oh I see - well thanks for that!
Yes you are right - we did alot of trialling to get the right balance. Alot of climbers talk about bridge adjustments to get their centre of balance.
Everyones center of balance is the same - middle of the pelvis. Categorically, it doesn't matter how long legs are in relation to torso, its the same for everyone. If we feel we need some support, we should correct our posture and strengthen our lower abdominals more. Triangulating the pelvis is what its all about, getting the right amount of pull on the pelvis and hams.
By having a waist belt around the lower back, this natural centre of balance is altered to create a more upright position. If the hams are allowed to drop, the pelvis tilts and that spells bad news for the lower back, pelvis and hips, and then of course the rest of the body that is connected to them. Even if the hams are supported adequately, a high back support prevents the spine from taking load low down where its taper is designed to handle it - the load goes through the mid back, causing round shoulders and hyper extension of the upper back.
We made the TFX bridge just long enough to give the advantage of a low tie in with sufficient slide from hip to hip.
For those that like loose leg loops, the shackle can be connected directly to the leg loop ring - this distance should match the length of the waist riser to triangulate the centre of the pelvis.
Maybe that sheds a little light on our design ethos? This is a good discussion on solving pelvic issues for chair design. In fig 6, you can see why TFX should fit all in depth of pelvis, as there is little difference between sizes. We invested in sizing where it mattered more: http://www.hermanmiller.com/hm/content/product/miscellaneous/021003_Aeron5.pdf
Yes you are right - we did alot of trialling to get the right balance. Alot of climbers talk about bridge adjustments to get their centre of balance.
Everyones center of balance is the same - middle of the pelvis. Categorically, it doesn't matter how long legs are in relation to torso, its the same for everyone. If we feel we need some support, we should correct our posture and strengthen our lower abdominals more. Triangulating the pelvis is what its all about, getting the right amount of pull on the pelvis and hams.
By having a waist belt around the lower back, this natural centre of balance is altered to create a more upright position. If the hams are allowed to drop, the pelvis tilts and that spells bad news for the lower back, pelvis and hips, and then of course the rest of the body that is connected to them. Even if the hams are supported adequately, a high back support prevents the spine from taking load low down where its taper is designed to handle it - the load goes through the mid back, causing round shoulders and hyper extension of the upper back.
We made the TFX bridge just long enough to give the advantage of a low tie in with sufficient slide from hip to hip.
For those that like loose leg loops, the shackle can be connected directly to the leg loop ring - this distance should match the length of the waist riser to triangulate the centre of the pelvis.
Maybe that sheds a little light on our design ethos? This is a good discussion on solving pelvic issues for chair design. In fig 6, you can see why TFX should fit all in depth of pelvis, as there is little difference between sizes. We invested in sizing where it mattered more: http://www.hermanmiller.com/hm/content/product/miscellaneous/021003_Aeron5.pdf
