Due to her discomfort, the 17-year-old Russian asked the Tour not to use its official Tretorn edition balls at this week's season-ending WTA Championships, but her request fell on deaf ears.

"They are heavy on my arm," Sharapova said on Tuesday, two days ahead of her opening match at the eight-women round robin event against compatriot Vera Zvonareva.

"It's something that the Tour and (CEO) Larry Scott have to look into. I'm sure the WTA doesn't want anyone to get injured."

Tour spokesman Darrell Fry said that after Sharapova made a private complaint a few weeks ago, the WTA consulted experts and other players as to whether the balls had become a problem but could not find any evidence that her assertion was true.

"There's no correlation at all between player injuries and Tretorn balls," Fry said.

"The health of our players is first and foremost in our minds. That's why we conducted blind tests with dozens of players last year to find the best ball, which turned out to be Tretorn.

"If there are complaints in the future, we'll look into them."

Also Read Sharapova knocks out Venus Agassi questions use of models as ball-girls Model ball-girls stir up storm

The WTA has a three-year contract with Tretorn but Sharapova and Zvonareva want to see a change as soon as possible.

"The most important thing is figuring out which ball isn't going to injure players," said Sharapova, who claims that the heaviness of the balls led to a pectoral injury at a tournament in Zurich three weeks ago.

The Russian also blames the balls for her shoulder injury in Philadelphia last week, when she was forced to pull out of her semi-final against eventual champion Amelie Mauresmo.

"It's very important to help players who are injured," she added.

Even if other players like Tretorn and are not getting injured, I think the best thing is to help the girls who are."

SURFACE ISSUES

Zvonareva, who reached the final in Philadelphia, agreed.

"I think we should have lighter balls for every tournament that's good on any surface," she said.

"In Philadelphia, my arm was sore and I had trouble with my left wrist, which I haven't had in a while.

"A lot of this depends on the surface. If you have heavy balls on a slow surface, you have time to prepare.

"In Philadelphia, the surface was faster and a lot of times you aren't in a good position, so you have to use your arm and wrist more. That's why the pain might come."

Frenchwoman Mauresmo, however, is opposed to a change of equipment.

"They are not much different to what we played with before," she said.

"Maria complained in Philly when she pulled out of our match but I didn't notice a difference. I don't feel they are heavier."

Third ranked Anastasia Myskina added that since nothing could be done this week, the players needed to grit their teeth and forget about it.

"We just have to play and not complain about it," Myskina said. "I've had pain before and you get used to playing in pain."