In the new snapshot, double-tapping the "Forward" key results in a running animation, but no increase in speed. Your field of view increases, but your forward speed is exactly the same as walking. Also, jumping is still increased in length as though you still had the forward momentum of running.
Environment
OSX Mountain Lion
Duplicate of MC-16143, please use the search function to see if your bug has already been submitted. Currently over 56% of tickets are being closed as duplicate.