title: Effect of aging and exercise on the tendon.
abstract: Here, we review the literature on how tendons respond and adapt to ageing and exercise. With respect to aging, there are considerable changes early in life, but this seems to be maturation rather than aging per se. In vitro data indicate that aging is associated with a decreased potential for cell proliferation and a reduction in the number of stem/progenitor-like cells. Further, there is persuasive evidence that turnover in the core of the tendon after maturity is very slow or absent. Tendon fibril diameter, collagen content, and whole tendon size appear to be largely unchanged with aging, while glycation-derived cross-links increase substantially. Mechanically, aging appears to be associated with a reduction in modulus and strength. With respect to exercise, tendon cells respond by producing growth factors, and there is some support for a loading-induced increase in tendon collagen synthesis in humans, which likely reflects synthesis at the very periphery of the tendon rather than the core. Average collagen fibril diameter is largely unaffected by exercise, while there can be some hypertrophy of the whole tendon. In addition, it seems that resistance training can yield increased stiffness and modulus of the tendon and may reduce the amount of glycation. Exercise thereby tends to counteract the effects of aging.
authors.affiliation: Institute of Sports Medicine Copenhagen, Department of Orthopedic Surgery, Bispebjerg Hospital and Center for Healthy Aging, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark.
authors.forename: Rene B
authors.initials: RB
authors.lastname: Svensson
authors.affiliation: Institute of Sports Medicine Copenhagen, Department of Orthopedic Surgery, Bispebjerg Hospital and Center for Healthy Aging, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark.|Department of Biomedical Sciences, Center for Healthy Aging, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark; and.
authors.forename: Katja Maria
authors.initials: KM
authors.lastname: Heinemeier
authors.affiliation: Institute of Sports Medicine Copenhagen, Department of Orthopedic Surgery, Bispebjerg Hospital and Center for Healthy Aging, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark.|Musculoskeletal Rehabilitation Research Unit, Bispebjerg Hospital, Denmark.
authors.forename: Christian
authors.initials: C
authors.lastname: Couppé
authors.affiliation: Institute of Sports Medicine Copenhagen, Department of Orthopedic Surgery, Bispebjerg Hospital and Center for Healthy Aging, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark.|Department of Biomedical Sciences, Center for Healthy Aging, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark; and.
authors.forename: Michael
authors.initials: M
authors.lastname: Kjaer
authors.affiliation: Institute of Sports Medicine Copenhagen, Department of Orthopedic Surgery, Bispebjerg Hospital and Center for Healthy Aging, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark; p.magnusson@sund.ku.dk.|Department of Biomedical Sciences, Center for Healthy Aging, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark; and.|Musculoskeletal Rehabilitation Research Unit, Bispebjerg Hospital, Denmark.
authors.forename: S Peter
authors.initials: SP
authors.lastname: Magnusson
mesh_terms: D000375:Aging / Q000378:metabolism / Q000502:physiology*; D000818:Animals; D003094:Collagen / Q000378:metabolism; D015444:Exercise / Q000502:physiology*; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism; D055070:Resistance Training / Q000379:methods; D013314:Stress, Mechanical; D013710:Tendons / Q000378:metabolism / Q000502:physiology*
chemical_list: D036341:Intercellular Signaling Peptides and Proteins; D003094:Collagen
keywords: exercise; fibril; fibroblast; stiffness; tendon