A trail that doubles back on itself is a trail that goes in one direction for a while, then almost reverses and goes back the direction it came from in a direction very close to or parallel to the way it came up. I'll try an example. Imagine you want to go from A (bottom) to F (top) The track goes from A to B, B to C, C to D, D to E, and E to F A..........................B ..............C..............................D ............................. E................................F Notice that the B-C and D-E section of the trail is going backwards a bit in the direction you came from. You would say that from B to C, and D to E the trail is doubling back on itself. Edit: I couldn't get the diagram to work too good, but I hope you get the idea. Imagine a straight line from B-C and D-E :) Just looked at this on my phone and it looks a bit confusing. I'll leave the answer in case it makes sense to someone :)

Goes back then back again in the opposite direction of the first direction.

Hi, it just means: "the track goes back the way it came from".