‘The difference is I’m black’: Richardson sees double standard over Valieva reprieve

• US sprinter missed Olympics after positive cannabis test
• Russian teen can compete in Beijing despite doping offence

The US sprinter Sha'Carri Richardson has questioned why the Russian figure skater Kamila Valieva has been allowed to compete at the Olympics while she was banned for a similar offence.

On Monday, the court of arbitration for sport (Cas) ruled 15-year-old Valieva could continue to compete at the Winter Olympics in Beijing despite registering a positive doping test in December. Richardson missed last summer's Olympics after testing positive for cannabis. Few people regard the drug as performance-enhancing and Richardson said she had smoked to relieve the pain she felt over the recent death of her mother.