Tyson Gay is focused on successfully defending his World Championship titles later this year because he believes he has yet to reach his full potential.
Gay completed the 100 and 200 metres double at the 2007 championships in Osaka but failed to qualify for the final of the 100 metres at the Beijing Olympics.
His defeat in the semi-final meant that the much anticipated Gay, Usain Bolt and Asafa Powell never materialised and the American sprinter could only watch on as Bolt took gold in a world record time.
Injuries hampered Gay for much of 2008 but he has refused to let them get him down and he returned to his best when clocked the third-fastest 200-metre time ever at the Reebok Grand Prix in May. He has now turned his attention to the World Championships and getting the better of Bolt.
"A lot of people have injuries that stop them reaching their full potential. A lot are discouraged when they don't win a lot of races, but I want to reach my full potential regardless if I have injuries or if I lose races," said Gay on Setanta Sports News.
"Even if I have ups and downs in my life I want to reach my full potential. If my full potential is 9.6 seconds I want to do it because I want to be the best that I can be. If my potential 9.5 I want to do it, I want to achieve it.
"I still have goals that I haven't achieved - time goals and world records."
Reflecting on his training, Gay added: "Last year I worked so hard to come up so short. This year, sometimes when I am tired I don't want to do it, but I do it anyway. I get off a five-hour flight and the next day I go and do my workout. I feel horrible but I just tell myself I have to do it.
"I have to train my mind in a way where it is more powerful than my body."
Jeremy Wariner, meanwhile, is determined to get back to his best after missing out on Olympic gold in Beijing.
Wariner was the hot favourite to capture the 400 metres title in Beijing with many tipping him to break Michael Johnson's world record in the process. However, he lost out to LaShawn Merritt in one of the surprises of the competition and he is working hard to get back to where he was earlier in his career.
"Last year I was running different races throughout the season and I wasn't running consistently like I should. That hurt me as the season went on because I didn't know which race I wanted to run.
This year I have been working on that to try to get back to where I was," said the double World 400 metre champion.
"I was getting out like I wanted to, but I was relaxing too much on the turn instead of working it like I used to so when I came off the turn I tried to force my kick instead of rolling into it. When I forced it, it was taking a lot of out me so I didn't have my usual finish.
"The Olympics was a tough defeat for me and I just wanted to improve on that this year and get back to where I was in years past. I am out here working as hard as I can in practice and giving it all I have, taking less rest as I try to build my strength up so when the time comes for me to run fast I will be ready for it."