title: Appendicular skeletal muscle mass: measurement by dual-photon absorptiometry.
abstract: Dual-photon absorptiometry (DPA) allows separation of body mass into bone mineral, fat, and fat-free soft tissue. This report evaluates the potential of DPA to isolate appendages of human subjects and to quantify extremity skeletal muscle mass (limb fat-free soft tissue). The method was evaluated in 34 healthy adults who underwent DPA study, anthropometry of the limbs, and estimation of whole-body skeletal muscle by models based on total body potassium (TBK) and nitrogen (TBN) and on fat-free body mass (FFM). DPA appendicular skeletal muscle (22.0 +/- 3.1 kg, mean +/- SD) represented 38.7% of FFM, with similar proportions in males and females. There were strong correlations (all p less than 0.001) between limb muscle mass estimated by DPA and anthropometric limb muscle areas (r = 0.82-0.92), TBK (r = 0.94), and total-body muscle mass based on TBK-FFM (r = 0.82) and TBK-TBN (r = 0.82) models. Appendicular skeletal muscle mass estimated by DPA is thus a potentially practical and accurate method of quantifying human skeletal muscle mass in vivo.
authors.affiliation: Department of Medicine, St. Luke's-Roosevelt Hospital Center, Columbia University College of Physicians and Surgeons, New York, NY.
authors.forename: S B
authors.initials: SB
authors.lastname: Heymsfield
authors.forename: R
authors.initials: R
authors.lastname: Smith
authors.forename: M
authors.initials: M
authors.lastname: Aulet
authors.forename: B
authors.initials: B
authors.lastname: Bensen
authors.forename: S
authors.initials: S
authors.lastname: Lichtman
authors.forename: J
authors.initials: J
authors.lastname: Wang
authors.forename: R N
authors.initials: RN
authors.lastname: Pierson
mesh_terms: D015502:Absorptiometry, Photon; D000273:Adipose Tissue / Q000033:anatomy & histology; D000886:Anthropometry; D001823:Body Composition; D015992:Body Mass Index; D001842:Bone and Bones / Q000033:anatomy & histology; D005121:Extremities; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D009132:Muscles / Q000033:anatomy & histology*; D009584:Nitrogen / Q000032:analysis; D011188:Potassium / Q000032:analysis; D012044:Regression Analysis; D012727:Sex Characteristics; D012984:Software
chemical_list: D009584:Nitrogen; D011188:Potassium