Originally Posted by Eddie
Well, I got curious and dug out my manual for my sewing machine and sure enough it has a "Triple Stretch Stitch" that does what others described above - 1 stitch forward, 1 stitch back, then 1 stitch forward again. So I tried it and it does indeed make a pretty sturdy looking stitch!
That stitch (I think) was originally designed to sew double knit fabrics; a single row of stitching will not stand up to the stretching of knits. Now that double knit fabric is not popular any more, I use mine mostly for mending t-shirts and sweatshirts/pants. It works very well for that.