title: The cross-sectional relationship between fortnightly exercise and knee cartilage properties in healthy adult women in midlife.
abstract: OBJECTIVE
  Exercise has been strongly promoted for the prevention of the major diseases of aging in women, such as cardiovascular disease and osteoporosis. However, conflicting data exist as to whether exercise benefits joint health and thus helps protect against degenerative processes such as knee osteoarthritis. The aim of this study was to examine the cross-sectional relationship between exercise and knee joint cartilage in women at midlife.
  
  
  METHODS
  A total of 176 women aged 40 to 67 years with no clinical knee osteoarthritis or history of significant knee injury were recruited from the community and had magnetic resonance imaging performed on their dominant knee to assess tibial cartilage volume and defects. The women completed a questionnaire to determine fortnightly exercise participation and frequency.
  
  
  RESULTS
  Fortnightly participation in exercise at an intensity that caused tachypnea and an increased pulse rate for at least 20 minutes was positively associated with the volume of the medial tibial cartilage (P=0.02). There was a tendency for the frequency of exercise at this intensity to be positively associated with medial tibial cartilage volume (P=0.07). Exercise participation was not significantly associated with the presence of knee cartilage defects.
  
  
  CONCLUSIONS
  Participation in exercise that causes tachypnea and an increased pulse rate for at least 20 minutes was associated with greater medial tibial cartilage volume, but not knee cartilage defects in non-healthcare-seeking women at midlife. More frequent exercise also tended to be associated with greater medial tibial cartilage volume. Although our findings need to be confirmed longitudinally, they provide further support for a beneficial effect of regular exercise on diseases related to aging.
authors.affiliation: National Health and Medical Research Council of Australia Centre of Clinical Research Excellence for the Study of Women's Health, Monash University Medical School, Alfred Hospital, Prahran, Victoria, Australia.
authors.forename: Fahad
authors.initials: F
authors.lastname: Hanna
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Teichtahl
authors.forename: Robin
authors.initials: R
authors.lastname: Bell
authors.forename: Susan R
authors.initials: SR
authors.lastname: Davis
authors.forename: Anita E
authors.initials: AE
authors.lastname: Wluka
authors.forename: Richard
authors.initials: R
authors.lastname: O'Sullivan
authors.forename: Flavia M
authors.initials: FM
authors.lastname: Cicuttini
mesh_terms: D000368:Aged; D002358:Cartilage, Articular / Q000502:physiology*; D003430:Cross-Sectional Studies; D015444:Exercise; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000502:physiology*; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000517:prevention & control; D012016:Reference Values; D012420:Running; D013977:Tibia / Q000502:physiology; D016387:Women's Health