I answered this but I can never post on the first try with this board and like an idiot I didn't save the post before posting it.
to knit back is to turn your work by changing hands and knitting back onto the left needle any stitches that have been knitted onto the right needle. this most often seems to be used in regards to Short Rows.
This is not to be confused with knitting backwards
which is something I heartily recommend for this pattern as all that changing over gets annoying. In this case you would be purling back but you know what I mean.
Here's a video for knitting backwardshttp://www.knitting-and.com/knitting/tips/backwards.html