Any ideas please?

I have started leaning for extra support and balance and I am doing it a lot in my workshop when I work my clay. I am using the edge of the table for added support. My neuro-physio wants me to use my knees instead and has suggested I try and get a knee height support bar. A friend has very sweetly said he will make me something but I was wondering if anyone could think of something I could adapt and use. Many thanks for any suggestions : )