(Reuters) - A reigning Olympic champion rediscovering his form, a defending world champion with a point to prove and the fastest man in 2022 will headline a packed 100 metres field when the World Championships get underway at Hayward Field in Eugene on Friday.

Olympic gold medallist Lamont Marcell Jacobs returns to the 100m big stage after muscle injuries ruled him out of several Diamond League meets and the Italian has been far from his best this season.