Hiinkan
The Hiinkan are a humanoid civilization native to a low-gravity planet. The Hiinkan physique and neural motor cortex is adapted to cope with a low gravity; on their homeworld they are virtually able to "fly". When exposed to Earth-normal gravity environments they need physical support to function. The type of support varies but includes wearing an external skeleton with integrated servomotors which helps by supporting the person's own skeleton, although this only functions for short periods of time. For longer-term physical support other forms of support are needed, like a wheelchair or an anti-grav unit. Only about 80,000 Hiinkans live in earth territory.