As running shoes become increasingly high-tech, the sport's governing body tries to regulate so that the athletes do not get too much help from their footwear.

Therefore, the International Athletics Federation has produced a list of 131 shoe models that are approved to compete in.

What has been aimed at is the thickness of the sole.

Now a shoe may have a sole that is at most 25 millimeters thick for 800 meter distances or longer, while the soles of marathon shoes may be 40 millimeters thick.

And, the shoes that Therese Johaug wore on June 11 at the Impossible Games in Oslo where she dreamed of 31.40.69 in 10,000 meters, which was both a personal record as well as the world year's best, yes those dojos are too thick to be on the union's okay list.

- I have not really had time to think much about this yet, but I reckon that there are other shoes you can run in, if I now feel like doing it, Therese Johaug told Norwegian NRK.

ARCHIVE: Here Johaug passes the World Cup qualifying limit of 10,000 meters (August 13):

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