US' Nike launches Alphafly 4 for marathon runners

Nike is introducing the Alphafly 4, a rebuilt marathon racing shoe with an Atomknit upper, ZoomX LT foam, updated Air Zoom units, a carbon-fiber Flyplate and Fast Shot outsole.
The company says the shoe offers 10 per cent more energy return and is 5 per cent lighter in a men's size 8.5; early limited sales begin September 17, before broader availability on October 29.