Nike's controversial Vaporfly shoes just avoided a ban. But future running shoes will face new regulations.

Crystal Cox/Business Insider

• • Nike's controversial Vaporfly shoes, worn by record-breaking marathoners, just avoided a ban ahead of the Tokyo Olympics.
  • New rules announced Friday permit the shoes already on the market to be worn in competition, but ban prototype shoes in competitions, which includes the Nike Alphaflys worn in the first ever sub-2-hour marathon.
  • Vaporfly soles give runners more energetic efficiency, but some researchers and runners think the shoes confer an unfair advantage.
  • Visit Business Insider's homepage for more stories.

Nike's controversial Vaporfly shoes have avoided a ban ahead of this summer's Tokyo Olympics.

World Athletics, the organization that governs most international track-and-field events, announced new shoe regulations on Friday. The ruling places an immediate, indefinite ban on shoes with more than one plate or with soles thicker than 40 millimeters. (The Vaporfly sole is exactly 40 millimeters in thickness, according to Runner's World.) Shoes with spikes attached by an additional plate must have a sole thickness of 30 millimeters or less.See the rest of the story at Business Insider

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