In the beta, you are much slower than people on live in the world linked below, while:
-Sprinting
-Crouching and sprinting
-Laying down and sprinting
Here is a video demonstration, that I have posted in the beta discussion channel:
This is the world with the issue:
Also the video doesn't show this, but in that world you can not jump at all in the beta.
If you switch back to live, you can jump.