An old back problem is keeping world 100 metres silver medallist Tyson Gay off the track when he should be training and racing, the American said on Thursday.
"The past couple of weeks I have been mentally drained, tired, frustrated because I am hurt almost every year and it is not fun," Gay said at a news conference for Saturday's New York Diamond League meeting in which he will not compete.
Gay, who has experienced knee, hamstring and groin injuries in the past, is hampered by tightness in his right hamstring, he said.
He has not trained for five days but hopes to resume practice on Friday.
"I think it is something coming from my back, something that happened to me years ago with the sciatica nerve that is causing my hamstring to tighten up," said Gay, who does not expect to compete again until July.
A failure to do speed work in practice before running the world's fastest time for a 200 metres straightaway in Manchester, England last month may have aggravated the nerve, Gay said.
"It could have shocked my body," Gay said.
"It (the hamstring) was a little bit tight before Manchester. It was a little sore after I ran," he added.
The frequent problems have left the U.S. 100 metres record holder so frustrated he plans to see a nutrition specialist this week.
"There is no reason why a 27-year-old should be getting injured every year," said the world's second fastest man behind Jamaican world record holder Usain Bolt.
"At this point in my life I am willing to sacrifice and do anything I can to stay healthy," Gay said.