Well, a "musculo-skeletal fitness
" test that appears to be pretty on target.
"Without worrying about the speed of movement, try to sit and then to rise from the floor, using the minimum support that you believe is needed."
5 points max for how well you sit, 5 max for rising.
There's a video link
in the article.
They scored 2002 middle aged people, followed them for about six years and found that the lower the score the higher the likelihood of not living out the next six years.
I tried it last night and got an eight by my reckoning. I think with some exercise I can get it to 10.