TUESDAY, Sept. 14 (HealthDay News) -- The risk of tendon injuries appears to be greater in female athletes with naturally higher levels of estrogen, a small European study suggests.

The findings suggest it may be a good idea to test estrogen levels in order to identify at-risk athletes so that extra precautions can be taken when planning their training program, said Katherine E. Burgess, of the University of Salford in Manchester, England, and colleagues in a news release.

In this study, researchers examined the knee tendons and estrogen levels at different times during the menstrual cycle in 23 active young women. None of the participants were taking birth control pills, which alter hormone levels.

The tendons in women with higher estrogen levels had differences in their mechanical properties, such as elongation and torque, that may lead to increased risk of injury.

However, the researchers found no connection between different times of the menstrual cycle and variations in estrogen levels that could affect tendon properties or injury risk.

"Thus, 'time of month' does not need to be considered when organizing training and competition schedules," the researchers wrote.

They added that more research is needed to prove their theory and to determine whether extra conditioning might help female athletes with higher estrogen levels.

The study was recently published in the Journal of Strength and Conditioning Research.

More information

The U.S. National Institute of Arthritis and Musculoskeletal and Skin Diseases has more about sports injuries.