It is certainly possible to detect and track the skeletal points of the body with a RealSense 400 Series camera, using software called the Nuitrack SDK.
https://www.youtube.com/watch?v=gMPtV4NXtUo
The Nuitrack SDK software is produced by a company called 3DiVi and has no linkages to the RealSense SDK software produced by Intel. With Nuitrack, you are using the RealSense camera hardware to interact with 3DiVi's own SDK software.
The link below gives advice about using Nuitrack SDK for posture recognition.
https://community.nuitrack.com/t/fitness-application-development-initial-questions/817
