Six-time Olympic champion Usain Bolt is tuning up to claim the sprint treble, whereby if successful he will win three gold medals for the third successive time.
Bolt is also aiming to break his own 200 metre world record in this event.
He won the 100 metres, 200 and the 4×100-metre relay gold medals in Beijing 2008, and the same three at London 2012.
The Jamaican says he is feeling in good shape as he attempts to do it for the third time in what will be his last Olympics.
Bolt suffered a hamstring injury earlier in the season and has only ran one 200-metre race this year, when he finished first at the Diamond League meeting in London last month. Since then he said he has been working well with his coach.
Bolt has the 100 metre and 200 metre world records and his biggest hope is to break the 200 metres and even run in a time below 19 seconds.
Bolt will come up against old rival, Justin Gatlin, of the United States in the 100 metres.