The four-time Paralympic Games gold medalist won a silver medal as part of South Africa's 4x400-meter relay at the world championships in Daegu, South Korea, last year.

CNN: 'Blade runner' makes unprecedented Olympic debut

Ennis broke through at the 2009 World Championships when she claimed gold in Berlin but last year in Daegu, South Korea, she relinquished her title to Russia's Tatyana Chernova.

CNN: STORY HIGHLIGHTS

His new personal best time, 0.41 seconds better than his previous fastest, could also allow him to compete in the World Athletics Championships, which take place in Daegu, South Korea later this year.

CNN: Blade runner Pistorius makes 400m Olympic qualifying time