TOKYO (Kyodo) -- Tokyo Olympic race walking silver medalist Koki Ikeda lodged an appeal Friday to the Court of Arbitration for Sport over his four-year ban for alleged blood doping handed out by the Athletics Integrity Unit in February.

"After consulting with many people involved, I've decided to appeal in order to return to competing as soon as I can and restore my honor," the 26-year-old said in a statement released by his corporate athletics team.

The Shizuoka Prefecture native achieved the best Olympic result by a Japanese racewalker when he won silver at the 2021 Games in the men's 20 kilometers. He was runner-up again at the 2022 world championships and placed seventh at the Paris Olympics last summer.

A 2023 blood test, however, showed changes in his hemoglobin and other values that exceeded the limit compared to his biological passport, which stores his blood data.

He was notified of the allegation by the AIU in June 2024 and was provisionally suspended in November. His appeal was not sustained before the ban was confirmed on Feb. 14.

Ikeda, who has maintained his innocence from the outset, was unable to compete at the Feb. 16 that served as a qualifying trial for September's world championships in Tokyo.

He is all but certain to miss out on a place for the 2028 Olympics in Los Angeles.