Humanoids from the low-gravity world Elaysia, who struggle to move under the gravity most other species take for granted.
The Elaysians come from Elaysia, a planet with exceptionally low gravity. Off their homeworld they find standard gravity crushing, and need mechanical support or anti-grav aids just to get about, which makes them rare in Starfleet service.
The best-known Elaysian is Ensign Melora Pazlar, who came to Deep Space Nine to chart the Gamma Quadrant. Fiercely independent, she resisted being treated as an invalid. Julian Bashir began a romance with her and developed a treatment that would let her walk in normal gravity, but she ultimately turned it down to remain who she was.