I have recently found that I cannot sprint when going up stair blocks, but I can sprint going down. I don't know if this is a feature or a bug, but I felt it was best to report it just in case.
MC-2987
Can't Sprint Going Up Stairs
Resolved
Fixed
0
Kevin Emery
(Unassigned)
Unconfirmed
Minecraft 1.4.4
Snapshot 13w05a
Retrieved
It's a feature(:
You can only sprint going up/down slabs and coming down from stairs(: