The seat height considering ease of most of the people in a population ( where we do not know who would be the intended user) a 25th percentile value of the popliteal height ( male-female combine d data ) from floor may be considered which in Indian case appears to be at 40cm, so that taller person can seat with little extended legs and shorter user can get adjusted with wearing footwear or automatically by the front edge curvature of the seat which is normally given to help bending of legs backward ( at 80 degree popliteal angle ) to assist raise from the seating position would support the foot rest on the floor.

 

 

For elbow rest height, an appropriate decision should be taken based on the activity pattern of the intended users.