title: Mid-femoral and mid-tibial muscle cross-sectional area as predictors of tibial bone strength in middle-aged and older men.
abstract: While it is widely acknowledged that bones adapt to the site-specific prevalent loading environment, reasonable ways to estimate skeletal loads are not necessarily available. For long bone shafts, muscles acting to bend the bone may provide a more appropriate surrogate of the loading than muscles expected to cause compressive loads. Thus, the aim of this study was to investigate whether mid-thigh muscle cross-sectional area (CSA) was a better predictor of tibial mid-shaft bone strength than mid-tibia muscle CSA in middle aged and older men. 181 Caucasian men aged 50-79 years (mean±SD; 61±7 years) participated in this study. Mid-femoral and mid-tibial bone traits cortical area, density weighted polar moment of area and muscle CSA [cm(2)] were assessed with computed tomography. Tibial bone traits were positively associated with both the mid-femur (r=0.44 to 0.46, P<0.001) and the mid-tibia muscle CSA (r=0.35 to 0.37, P<0.001). Multivariate regression analysis, adjusting for age, weight, physical activity and femoral length, indicated that mid-femur muscle CSA predicted tibial mid-shaft bone strength indices better than mid-tibia muscle CSA. In conclusion, the association between a given skeletal site and functionally adjacent muscles may provide a meaningful probe of the site-specific effect of loading on bone.
authors.affiliation: Centre for Physical Activity and Nutrition Research, School of Exercise and Nutrition Sciences, Deakin University, 221 Burwood Highway, Burwood, VIC 3125, Australia. timo.rantalainen@deakin.edu.au
authors.forename: T
authors.initials: T
authors.lastname: Rantalainen
authors.forename: R
authors.initials: R
authors.lastname: Nikander
authors.forename: S
authors.initials: S
authors.lastname: Kukuljan
authors.forename: R M
authors.initials: RM
authors.lastname: Daly
mesh_terms: D000368:Aged; D001696:Biomechanical Phenomena; D005269:Femur / Q000000981:diagnostic imaging* / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000000981:diagnostic imaging* / Q000502:physiology; D013977:Tibia / Q000000981:diagnostic imaging* / Q000502:physiology; D014057:Tomography, X-Ray Computed