I have noticed a few glitches related to PVP and sprinting. Here are a some:
1. You stop sprinting when you hit someone (with a sword?).
2. If someone hits you while you are sprinting, you stop sprinting.
3. You stop sprinting when you start to run on stairs/half slabs.
Linked issues
Comments 2
Duplicate of MC-242.
If this is meant to happen and is not a bug, then it is an annoyance. Not being able to sprint while being attacked makes it impossible to escape an attacker if he's attacking you. It's also really hard to run away up stairs because people can easily attack while running up stairs.