Exercise needs for someone with physical disabilty

Hi,
We are a group of third year engineers looking to design an exercise device for someone with tetra Amelia (lacking all four limbs) or quadriplegia, we are in the stages of doing research into the needs . If anyone has ideas or information connected with this subject we would be grateful for any help.
This is our mission statement
''We aim to Design a fun, safe, durable and practical independent mobility device that can be incorporated into the daily routine of someone with a severe physical disability'