Incline walking or sprints for fat burning?

[Dan.]

let's say walking at 4.0 mph incline 10.0 for 31:00 or walking at 4 mph incline 1.0 & sprinting at 9 mph incline 3 then walk then run then walk, run ect,ect. Which one would be better for fat burning? Is there really a difference? I find that their both hard in their own ways.... any advice? Any tips or suggestions to tweak my regimen? Thanks in advance.