title: Sex Hormones and Tendon.
abstract: The risk of overuse and traumatic tendon and ligament injuries differ between women and men. Part of this gender difference in injury risk is probably explained by sex hormonal differences which are specifically distinct during the sexual maturation in the teenage years and during young adulthood. The effects of the separate sex hormones are not fully elucidated. However, in women, the presence of estrogen in contrast to very low estrogen levels may be beneficial during regular loading of the tissue or during recovering after an injury, as estrogen can enhance tendon collagen synthesis rate. Yet, in active young female athletes, physiological high concentration of estrogen may enhance the risk of injuries due to reduced fibrillar crosslinking and enhanced joint laxity. In men, testosterone can enhance tendon stiffness due to an enhanced tendon collagen turnover and collagen content, but testosterone has also been linked to a reduced responsiveness to relaxin. The present chapter will focus on sex difference in tendon injury risk, tendon morphology and tendon collagen turnover, but also on the specific effects of estrogen and androgens.
authors.affiliation: Department for Public Health, Section for Sport Science, Aarhus University, Dalgas Avenue 4, 8000, Aarhus, Denmark. mhan@ph.au.dk.
authors.forename: Mette
authors.initials: M
authors.lastname: Hansen
authors.affiliation: Institute of Sports Medicine, Department of Orthopedic Surgery M, Bispebjerg Hospital, Copenhagen, Denmark.|Center for Healthy Aging, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Michael
authors.initials: M
authors.lastname: Kjaer
mesh_terms: D000293:Adolescent; D005260:Female; D012739:Gonadal Steroid Hormones / Q000378:metabolism*; D006801:Humans; D008297:Male; D052256:Tendinopathy / Q000503:physiopathology*; D013710:Tendons / Q000378:metabolism*
chemical_list: D012739:Gonadal Steroid Hormones
keywords: ACL rupture; Biomechanical properties; Collagen; Cross-links; Estradiol; Estrogen; Fascicles; Gender; Injury risk; Insulin-like growth factor I (IGF-I); Joint laxity; Knee laxity; Progesterone; Relaxin; Sex; Sex hormones; Tendinopathy; Testosterone