Source: Wolters Kluwer Health: Lippincott Williams & Wilkins
Newswise — In female athletes with chronically higher estrogen levels, differences in the mechanical properties of tendons may lead to a higher risk of injury, according to a study in The Journal of Strength and Conditioning Research, official research journal of the National Strength and Conditioning Association. The journal is published by Lippincott Williams & Wilkins , a part of Wolters Kluwer Health, a leading provider of information and business intelligence for students, professionals, and institutions in medicine, nursing, allied health, and pharmacy.
“As such, female athletes may benefit from systematic determination of their estrogen levels so as to allow their coach/team manager to take extra precautions when deciding on a training plan for those ‘at risk females,'” according to the new study, led by Katherine E. Burgess, Ph.D., of University of Salford, Manchester, United Kingdom. However, the study finds no evidence that variations in hormone levels during the menstrual cycle affect tendon properties or injury risk.
Tendon Properties Don’t Vary with Monthly Changes in Hormone Levels…
The researchers used several techniques to measure the mechanical properties of the patellar (knee) tendon in 23 active young women. The women were studied at different times during the menstrual cycle: from day 1 to 4, day 12 to 14, or day 20 to 23 after menses.
Hormone levels—which vary at different phases of the menstrual cycle—were measured as well. The women in the study were not taking oral contraceptives, which alter hormone levels.
None of the tendon properties measured—such as elongation, torque, strain, or others—varied according to time of the menstrual cycle. This was consistent with previous evidence suggesting “no significant effect of menstrual cycle phase on maximal strength or injury risk.”
…But Women with Higher Estrogen Levels May Be at Higher Injury Risk
Nevertheless, the data showed a complex interaction between hormone levels, menstrual cycle phase, and tendon properties. Levels of the hormone estradiol, combined with tendon force, explained nearly one-fifth of the variation in a key measure of tendon stiffness. This suggested that individual differences in hormone levels between women could influence tendon characteristics, and thus potentially affect the risk of injury.