Elaysia

Elaysia, known to its native species as Gemworld, is home to the Elaysian people.

This planet, though classified as Class M, has a much lower surface gravity than Earth or Vulcan.

Only a handful of Elaysian have left the homeworld; the first in Starfleet was Melora Pazlar.
In order to move in gravity different than their planet's, people of this world need assistance from mobility aids such as anti-gravity chairs.
Neuromuscular treatments to condition their bodies are also possible, but doing so does mean an Elaysian would not be able to return to their home planet ever again.

This planet became a Federation member in or before the year 2378.