Gay admitted he was exhausted after nine races in Japan

The new world 100m and 200m champion will only take part in the 4x100m relay for the US team in Switzerland.

Double Osaka winner Gay said: "Zurich is a very special meet for me, so I'm sorry that I cannot run in the 100m.

"But I look forward to helping my US team-mates win the Zurich Trophy, and I appreciate the understanding of the organisers here."

The US relay team will run with the same personnel, and in the same order, as they did during their winning performance at the World Championships in Osaka last Saturday.

Meanwhile, fellow American Xavier Carter is looking forward to running in the 200m as he returns from an injury to his right leg sustained during the US trails prior to the Osaka championships.

"Now I'm back in shape I felt I had to come here and compete to the best of my abilities to see where I am at," said Carter.

"If I was in shape and at the worlds I do not see why I would not have got gold medals. I feel that if I am injury free and in top shape then it is hard to beat me.

"It is about proving to myself that I'm back and injury free. I feel I'm strong and 100%."