Japan's 75-year-old equestrian Hiroshi Hoketsu will not be competing in this summer's Rio de Janeiro Olympics after he was unable to meet the criteria to join a qualifying trial for the Japanese team, Kyodo News learned Tuesday.

Hoketsu, who made his Olympic debut in Tokyo in 1964 and was the oldest athlete to compete in the 2012 London Games at the Japanese record of 71, has been training in the Netherlands and Germany but hadn't been able to take part in competitions after his horse fell ill.

The Japan Equestrian Federation has been demanding the riders mark qualifying standard scores set by the International Federation for Equestrian Sports by May 23 in order to take part in its qualifying trial.

"I don't want to push the horse, so unfortunately I have given up upon the dream of competing in the Rio Olympics," Hoketsu is said to have told sources. "There's nothing decided about the future. First I'd like to prioritize getting the horse well again."

Hoketsu would have become the oldest athlete to compete in the Olympics had he qualified Rio, overtaking Swedish shooter Oscar Swahn, who participated in the 1920 Antwerp Games at the age of 72.

Hoketsu was aiming for his fourth Olympics after also appearing in the 2008 Beijing Games by winning one of four spots available for Japan.