If you have locked the lean in place (2xQ or 2xE) and start fast sprinting using Turbo or Fast forward, you will run considerably slower until you have disabled the lean by pressing Q or E again. The same happens if you hold down the lean key while running.
Annotated video: http://youtu.be/U4CRk3nlgcE
and
Type: Public Alpha
Branch: Stable
Version: 0.5.102571
This should be fixed by leaning being automatically cancelled when you start running or sprinting.
You can get into trouble easily when you need to start running and you can't figure out why you only walk!
EDIT: Eman, that reminds me. Perhaps to avoid problems with TrackIR, the game can save the lean state like when crouch-running; that way you go back to lean when you stop or walk. This would stop your view in TrackIR going out of alignment quickly, but it's not a crucial feature.
Also happens with the trackIR (or any other analog lean method), if you lean a little bit.
When full turbo running there is no change in animation, just in speed, from leaning, but when turbo running and low on stamina (tired sprinting) the character both leans and is slowed somewhat. When simply moving forward and leaning, the speed is that of combat mode, and the weapon is raised into the combat stance. I like how this functions for everything except the full turbo mode. If there is no change in animation, then the speed shouldn't be affected, but for the other sub modes, I like it.
Just assign 'Lean left' and 'lean right' to shift (sprint) key.
Works with TrackIR too
Issue closed as obsolete. If you encounter this problem again, please create another ticket. Thank you.