WASHINGTON (AP) - Athletes who use the energy-building supplement creatine can train without raising their risk of injury, researchers say.

"Now we are seeing trends; everybody is finding similar results," said researcher Mike Greenwood of Arkansas State University.

Some preliminary reports even indicate the risk of injury is lower among athletes who take the supplement. Although these are not definitive studies, the pattern of the findings argues against some criticisms of the training aid.

Creatine, which is present naturally in the body, works by increasing the muscle's ability to refuel quickly. Supplementation is aimed at making sure enough creatine is always available for the job.

Greenwood and his colleagues compared Arkansas State baseball players who were using creatine with those who were not. Users reported fewer cases of muscle pulls or strain, missed practices due to injury, and cramping.

Users knew they were getting creatine, leaving open the possibility that the knowledge may have affected their training plans or expectations of results. However, their workouts were carefully monitored and did not deviate from what researchers or the team trainer expected, Greenwood said.

Researchers also had players report on signs of overtraining. The scientists found no perceived differences in fatigue suffered by creatine users and nonusers.

However, there were indications that users were less likely to feel they were overtrained and were less likely to report arm and shoulder fatigue, while nonusers were more likely to report feeling they were falling behind in their training.

The findings were reported at several scientific meetings. They amount to early results from an ongoing project to determine the relative risks faced by users and nonusers, said exercise physiologist Conrad Earnest of the Cooper Institute, a Dallas-based research organization that focuses on exercise.

Earnest's role is to combine results from Greenwood and other collaborators into a database large enough to let statisticians draw more meaningful conclusions. Data so far show that creatine users don't have more cramping or muscle tears than do nonusers, Earnest said.

Greenwood and his colleagues noted earlier reports that athletes using creatine had cramping and other problems they attributed to creatine. And Earnest said pro football trainers have blamed creatine for such problems. But those claims have not stood up to repeated scientific examinations, the researchers said.

The current findings do not surprise researcher Jeff Volek of the University of Connecticut. Creatine can help athletes get in some extra lifts in training, or some extra force in a game, but the effect is not so powerful that athletes "can exceed breaking points for muscle tendons and fibers," he said.

"All creatine is doing is letting you do a few extra reps in weight training, or cut a tenth of a second off your time," Volek said. "You are looking at a 5 to 10 percent performance improvement."

Athletes on creatine might overtrain and might hurt themselves, but this would be the result of the athletes expecting to do more than they can, Volek said. "If you want to go from training four days to training seven days, that could lead to overtraining, but that's not creatine's fault," he said.

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