Race walking - when does it become running?

Look at the photo below.  It was taken at an indoor athletics event in Sheffield and has been converted to black and white for clarity.  Is this walking, or is the athlete running?

Now, look at the IAAF Rule 230 which covers race walking events:
"Race Walking is a progression of steps so taken that the walker makes contact with the ground, so that no visible (to the human eye) loss of contact occurs...."

So, it is solely up to the eyes of the 6 track judges as to whether contact is being continually made - not the lens of the camera which, as in many sports now, sees so much detail.