It is not a true running stitch - only looks that way from the top. The machine has a hook that pulls a loop of the bobbin thread to the top of the fabric, feed dogs push the fabric the required "stitch length" then the loop is poked back into the fabric and the loop is secured from underneath. The stitching on the back looks like couching. I don't see any way that one would be able to do free motion quilting on this machine, only straight lines and curves. There is a special 3-step technique just to do a pivot.
Here's a PDF of the manual: