Women spend about half of their adult lives in an estrogen-deficient state.(1) Because of this deficiency, it’s estimated that 80% of menopausal women experience symptoms interfering with their quality of life.(4) One area of life significantly impacted by menopause is physical activity and accompanying changes in performance, adaptation, and injury risk.(1)
While the effects of estrogen on bone structure and function have been studied extensively, less data is available on the direct and indirect effects of estrogen on the musculoskeletal functions of ligaments and tendons. Whereas estrogen improves bone and muscle function, it decreases stiffness in tendons and ligaments.(2)
There is a direct relationship between laxity and rupture in ligaments such as the ACL.(4) A stiffer ligament is preferred to maintain joint stability. In 2002, Japanese researchers from Hiroshima University found that knee laxity is dependent on female hormones. This supports the finding that ACL ruptures occur 2 to 8 times more often among females than males. In addition, when estrogen concentration increases during a female’s menstrual cycle, her knee laxity increases putting her at a higher risk for ACL injuries.(2)
However, the relationship between estrogen and tendons is more contradictory. As is the case for ligament injuries, the risk for tendon injuries in premenopausal women is higher than that for postmenopausal women.(3) A stiffer tendon, resulting from decreased estrogen, can improve performance by transmitting the force produced by a muscle quicker to the connecting bone. But, if a tendon becomes too stiff, a strain concentration is produced on the muscle which can lead to more injuries.(2)
Hormone replacement therapy, or HRT, is a common consideration for women experiencing menopausal symptoms. Researchers at the University of California studied the effect of estrogen on musculoskeletal performance and injury risk. Data suggests that even though HRT improves muscle and bone function through increased mass, long-term HRT use can lead to a decrease in tendon cross-sectional area. A 2009 study conducted to determine the effect of HRT on Achilles tendon size in female twins suggests HRT inhibits tendon adaptation during physical activity.(3) The result may be small, brittle tendons connecting bigger muscles to bigger bones. This mismatch can result in strains and promote injury. While HRT is beneficial for musculoskeletal function in postmenopausal women, extra care should be taken to maximize tendon function.(2)
Does the tendency for or resistance to injury for a postmenopausal woman depend entirely on the effects of estrogen? Not according to a 2017 Finnish study conducted on more than 900 women. Study participants ranged in age from 47 to 55. Of the participants, 233 were categorized as premenopausal, 381 were perimenopausal, and 299 were postmenopausal. Menopausal state was determined through each participant’s serum concentration of follicle-stimulating hormone which rises and falls throughout the menstrual cycle and menopause.(1,2) Results showed that the postmenopausal women had a handgrip force that was 12.0 N weaker and a vertical jumping height 1.1 cm lower than those who were premenopausal. However, physically active peri- and postmenopausal women performed better in a 6-minute walking test and in maximal knee extension strength tests than their less active counterparts and to a level showing no statistical difference when compared to premenopausal women.(2)
According to the study’s authors, the physical activity level of the peri- and postmenopausal women proved to be an important determinant of their test performance. Greater levels of physical activity appear to impede the possible negative effects of menopausal factors on muscle strength and power. The researchers further state that the decline in physical performance often seen during menopause may be due in part to estrogen deficiency and in part to a decline in the level of physical activity.(1)
Remaining active in all life stages, especially during and after menopause, is important to counteract the natural decline of aging. Esurgi is developing the Joint Spy, a knee sleeve that provides real-time feedback of the wearer’s movements during high-risk activities. The clinical screening tool can be used to identify individuals who are at greater risk for knee-joint injuries and thereby yield a higher quality of life through preventative strengthening and training.
- Bondarev, D., Laakkonen, E., et al (2018). Physical performance in relation to menopause status and physical activity. Menopause: The Journal of the North American Menopause Society, 25(12). doi: 10.1097/GME.0000000000001137.
- Chidi-Ogbolu, N. and Baar, K. (2018). Effect of Estrogen on Musculoskeletal Performance and Injury Risk. Frontiers in Physiology. 9(1834). https://dx.doi.org/10.3389%2Ffphys.2018.01834.
- Finni, T., Ronkainen, P., et al. (2009). Combination of hormone replacement therapy and high physical activity is associated with differences in Achilles tendon size in monozygotic female twin pairs. Journal of Applied Physiology. 106(4). https://doi.org/10.1152/japplphysiol.91439.2008
- Leblanc, D.R., Schneider, M., et al (2017). The effect of estrogen on tendon and ligament metabolism and function. Journal of Steroid M=Biochemistry and Molecular Biology. 172 (2017). https://doi.org/10.1016/j.jsbmb.2017.06.008.