I finally discovered a set up for my sewing machine pedal, that is comfortable to me and wanted to share it in case it would help any of you. I know there are no-slip pads (I have one) and other ways to set the sewing machine pedal, like wearing heeled shoes or turning the pedal around but none of these worked for me and after hours of machine quilting I would have a very sore knee, even the next day.
Finally I placed a piece of 1” thick packing foam up against the back end of the pedal, extending it past the length of my foot (it’s kind of a cross between Styrofoam & foam rubber, it has a little give but mostly firm support). I can move my foot up and down on it and my entire foot is supported on the foam and pedal. I can quilt (and sew) for hours now and there is no strain on my leg or knee.
The box is only there because my patchwork of carpets overlaps in that area but it too keeps the pedal in place. I do keep my other foot slightly elevated which helps keep my back and hips straight.
Disclaimer – Though this has worked for me, I give no guarantee that it will for anyone else.