The following report by medical editor Marilyn Brooks first aired on Channel 4 Action News at 5 p.m. on Feb. 13, 2006.

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Health food stores have entire sections devoted to the way that athletes can get an edge.

A new study recently put two popular supplements to the test with some surprising results.

When seconds count, athletes want any competitive edge they can get.

"As far as shaving off seconds, the more -- I mean, it's crucial," said rower Katie Poling.

Researchers wondered if the sugar supplement ribose is really best at improving athletic performance

They compared two groups of female rowing teams for eight weeks.

One group took ribose, the other dextrose -- a sugar in sweeteners and sport drinks.

"We were very surprised when the dextrose group actually ended up rowing faster than the ribose group," said Dr. Michael Macknin of the Cleveland Clinic.

Previous studies show ribose helps casual and professional athletes keep their bodies at peak performance in long distance marathon events. But this study found in shorter events, like rowing, the ribose group was 10 seconds slower than the dextrose group.

That surprised Poling, but she said everyone on her team started the study with different ability levels.

"There's more factors involved, other than just taking something like dextrose," said Poling.

Macknin agrees his study was small -- the results inconclusive -- but he thinks that "what needs to be done is to do additional studies and find out what is the right dose of dextrose to most improve athletic performance."

Experts say supplements may help -- emphasis on the word "may" -- but they are no substitute for hard work and lots of sweat.

And that's good advice for everyone who believes the supplement hype.