title: Muscle strength and areal bone mineral density at the hip in women: a cross-sectional study.
abstract: BACKGROUND
  Muscle strengthening exercises are promoted for building and maintaining a healthy skeleton. We aimed to investigate the relationship between muscle strength and areal bone mineral density (BMD) at the hip in women aged 26-97 years.
  
  
  METHODS
  This cross-sectional study utilises data from 863 women assessed for the Geelong Osteoporosis Study. Measures of hip flexor and abductor strength were made using a hand-held dynamometer (Nicholas Manual Muscle Tester). The maximal measure from three trials on each leg was used for analyses. BMD was measured at the hip using dual energy x-ray absorptiometry (DXA; Lunar DPX-L). Total lean mass, body fat mass and appendicular lean mass were determined from whole body DXA scans. Linear regression techniques were used with muscle strength as the independent variable and BMD as the dependent variable. Models were adjusted for age and indices of body composition.
  
  
  RESULTS
  Measures of age-adjusted hip flexor strength and hip abductor strength were positively associated with total hip BMD. For each standard deviation (SD) increase in hip flexor strength, the increase in mean total hip BMD (SD) was 10.4 % (p = 0.009). A similar pattern was observed for hip abductor strength, with an increase in mean total hip BMD of 22.8 % (p = 0.025). All associations between hip muscle strength and total hip BMD were independent of height, but were nullified after adjusting for appendicular lean mass or total lean mass.
  
  
  CONCLUSIONS
  There was a positive association observed between muscle strength and BMD at the hip. However, this association was explained by measures of lean mass.
authors.affiliation: Epi-Centre for Healthy Ageing, IMPACT SRC, School of Medicine, Deakin University, PO Box 281, Geelong, VIC, 3220, Australia. juliep@barwonhealth.org.au.|Department of Medicine, NorthWest Academic Centre, The University of Melbourne, St Albans, VIC, Australia. juliep@barwonhealth.org.au.|University Hospital Geelong, Barwon Health, Geelong, VIC, Australia. juliep@barwonhealth.org.au.
authors.forename: Julie A
authors.initials: JA
authors.lastname: Pasco
authors.affiliation: Epi-Centre for Healthy Ageing, IMPACT SRC, School of Medicine, Deakin University, PO Box 281, Geelong, VIC, 3220, Australia. khollo@barwonhealth.org.au.
authors.forename: Kara L
authors.initials: KL
authors.lastname: Holloway
authors.affiliation: Epi-Centre for Healthy Ageing, IMPACT SRC, School of Medicine, Deakin University, PO Box 281, Geelong, VIC, 3220, Australia. sharob@barwonhealth.org.au.|Department of Medicine, NorthWest Academic Centre, The University of Melbourne, St Albans, VIC, Australia. sharob@barwonhealth.org.au.
authors.forename: Sharon L
authors.initials: SL
authors.lastname: Brennan-Olsen
authors.affiliation: Epi-Centre for Healthy Ageing, IMPACT SRC, School of Medicine, Deakin University, PO Box 281, Geelong, VIC, 3220, Australia. david.moloney@barwonhealth.org.au.
authors.forename: David J
authors.initials: DJ
authors.lastname: Moloney
authors.affiliation: Epi-Centre for Healthy Ageing, IMPACT SRC, School of Medicine, Deakin University, PO Box 281, Geelong, VIC, 3220, Australia. markk@barwonhealth.org.au.|Department of Medicine, NorthWest Academic Centre, The University of Melbourne, St Albans, VIC, Australia. markk@barwonhealth.org.au.|University Hospital Geelong, Barwon Health, Geelong, VIC, Australia. markk@barwonhealth.org.au.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Kotowicz
mesh_terms: D015502:Absorptiometry, Photon; D050154:Adiposity; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D015519:Bone Density; D003430:Cross-Sectional Studies; D005260:Female; D006304:Health Status; D006621:Hip Joint / Q000000981:diagnostic imaging / Q000502:physiology*; D006801:Humans; D016014:Linear Models; D008875:Middle Aged; D053580:Muscle Strength; D053581:Muscle Strength Dynamometer; D018482:Muscle, Skeletal / Q000502:physiology*; D010384:Pelvic Bones / Q000000981:diagnostic imaging / Q000502:physiology*; D012737:Sex Factors