Originally Posted by gale
I use a stretch stitch too. It's not a zig zag. It goes forward, back, forward like a triple stitch. On the machine stitch guide it looks like three lines next to each other. I don't understand how it's stretchy but it is. I also use a longer stitch on any knits.
My bet is it isn't stretchy, but it adds a lot of strength so that the stitching line doesn't break when the fabric is stretched. My machine has that kind of stitch but I rarely use it because it takes 3 times as long to stitch a seam.