Polio and chair

1n 1952 i had polio, in iron lung, muscle transplants from leg to stomach, and 97 percent spinal fusion.

I spend a lot of time on the ground.  Either gardening, or doing exercises.

My problem is that I can't get up from the ground.  However, I can easily rise from a chair.   I believe most of my problems eminent from getting of the ground, onto my knees, Pressing my hands into the seat of a chair, and putting all my weight on my good leg to left up and slid sideways onto the chair.   It is physically exsausting and painful

I want to purchase a square board about the size of a persons buttocks.   I would get on my knees, sit back on it, push a lever and rise 3ft.

Is there anything like that out there to purchase