I'm almost certain this is a 'known' but I'll post it anyway.
Your player becomes stuck on the spot whilst running full sprint.
occurs when a gun/rifle is equipped in hands, the player is sprinting and during the sprint attempts to aim down sight but continues running.
Rifle in hand (haven't tried many weapons) - begin sprinting - while sprinting single right click (don't stop to aim down the sights, assume it was an accidental click) - within the next moment or two your character will begin to seize up before hitting an invisible wall.
The user can stop sprinting, move left or right in order to break out of the 'stuck' position.
Appears to be 100% reproducible in exp .58.
First seen in .57
Hello K-2 and thank you for the report.
This is a known issue (#0024892) and it has been scheduled for a fix.
Regards,
Geez