Kenyan marathon runner Lawrence Cherono has been handed a seven-year ban for breaching doping rules, the Athletics Integrity Unit (AIU) announced Wednesday.

The 35-year-old runner, who won the Boston and Chicago marathons in 2019, provided an out-of-competition urine sample in May 2022 which revealed the presence of the prohibited substance trimetazidine.

"The AIU has banned Lawrence Cherono (Kenya) for 7 years from 16 July, 2022 for presence/use of a prohibited substance (trimetazidine), tampering or attempted tampering with any part of doping control," the AIU said in a statement.

Cherono's ban has been backdated to July 2022, when his provisional suspension began, meaning the Kenyan will be unable to compete until 2029.

The positive test earned the runner a four-year ban, plus an additional four years for "submitting misleading, forged/falsified information", the AIU indicated.

The total eight-year ban was reduced by one year due to Cherono's "early admission and acceptance of (the) sanction".

Kenya and its long-distance runners have been the source of a large number of doping cases in recent years. In April 2023, the AIU denounced large-scale doping in the country.

Trimetazidine is a blood flow booster known commonly as TMZ and was also detected in Russian skater Kamila Valieva during the 2022 Beijing Winter Olympics.

The World Anti-Doping Agency (WADA) came under pressure in April after it was revealed 23 Chinese swimmers tested positive for trimetazidine ahead of the Tokyo Olympics in 2021.

WADA's decision on the matter was that the swimmers were allowed to compete after accepting China's findings that they had ingested it unwittingly from food during a meet in late 2020 and early 2021.