Hi Gaby, good question.... Once the lumbar is no longer so tight, it is easier to sit truly upright on one's sitz bones without strain, but I think, because it's a structural size issue and not just a tightness issue, it's best to use the supports for ideal alignment. Also when one's knees are bent so much (when they are above sitz bones level) it can create extra tightness in the hip flexors - again merely because of the physics of it, not just the individual's tightness. But try it both ways (on your own body - if you're short like me, sit on a moon box to approximate what tall folks feel), see what you feel/think, and let me know!
Thank you so much Ruth, such great information. I've tried some of these tricks but you've given me some more tools. I have some clients that will benefit so much from this. Thanks Ruth and PA!
Thanks, Tanja! Two years ago at the PMA convention, there was a man (forget his name now) who was making reformers in 3 different sizes, one for children and I think one for tall people in addition to a regular average size. I thought that was such a good idea....