Bolt has injured hamstring, status for Rio Games in doubt (Yahoo Sports)

Usain Bolt’s Olympic quest is in doubt, after the sprint superstar left his country’s national championships with a hamstring injury shortly before he was going to run the 100-meter final. Bolt’s longtime rival Yohan Blake won the 100 title and formally qualified for the Rio de Janeiro Olympics – but only after a false-start disqualification call against him was overturned after review.