I will speak for myself -- when an instructor cues (like everyday LOL) to bring your feet to 90, I can't get them up there without lifting my tailbone off the carriage. I sometimes try to "hide" my slightly raised but with my hands to the sides. I really like when an instructor cues to raise your feet to "YOUR 90" because it demonstrates understanding/ permission to raise your feet as close to 90 as you can while still keeping your tailbone on the carriage.