British Olympic middle distance medal contender Kelly Holmes has admitted concerns about her preparations for the Athens Games.
Holmes, who races in her first event of the summer season in the Czech Republic on Tuesday, said: "My training hasn't gone as well as I expected.
"I know I sometimes demand too much of myself but I don't think I have really achieved as much as I wanted to do.
"The race here in Ostrava has now become a very big test for me."
The Commonwealth champion is aiming for 1500m glory in Athens but is maintaining her speed work in case a last-minute problem, makes the 800m a better option.
"I want to do the 1500m," said Holmes, 34, a finalist over the distance in the last two Games, and a bronze medallist at 800m in Sydney.
"But I know from experience I have to be prepared for
any eventuality.
"I've had a wonderful period this winter of staying injury free. But, as I have learned to my cost in the past, you never know what might be around the corner.
"But if I stay injury-free, I am sure I will be challenging for a medal."
Also competing in Tuesday's IAAF Super Grand Prix meeting, Jo Fenn and Jade Johnson - both genuine Olympic medal prospects - face tough opponents in their 800m and long jump competitions.
Fenn, who won world indoor bronze this year, tackles Holmes' training partner Maria Mutola, while Johnson takes on Heike Drechsler, Fiona May and Marion Jones.
Donna Fraser, fourth in the 400m in Sydney, returns to action after three injury-plagued seasons.
Rob Newton is in a quality 110m hurdles field which includes reigning world champion Allen Johnson and other top American Duane Ross, Larry Wade and Terrence Trammell.
