title: Analysis of body-composition techniques and models for detecting change in soft tissue with strength training.
abstract: The purpose of this study was to compare the ability of various body-composition assessment techniques to detect changes in soft tissue in older, weight-stable women (50-70 y of age) completing a 1-y randomized, controlled trial of progressive resistance training. The intervention group (n = 20) performed high-intensity strength-training 2 d/wk with five different exercises; the control group (n = 19) was untreated. Hydrostatic weighing, 24-h urinary creatinine, computed tomography of thigh sections, total body potassium, and tritium dilution techniques were used to measure increases in total fat-free mass (FFM) and the muscle and water components of FFM. A decrease in fat mass (by hydrostatic weighing) was seen in the strength-trained women compared with the control subjects (P - 0.01-0.0001). Anthropometry, bioelectric impedance, dual-energy X-ray absorptiometry, and total body nitrogen and carbon did not measure any significant change in soft tissue. The choice of a body-composition technique is important when designing a study expected to affect soft tissue, because not all techniques available are precise enough to detect small changes.
authors.affiliation: Jean Mayer US Department of Agriculture Human Nutrition Research Center on Aging at Tufts University, Boston, MA 02111, USA.
authors.forename: M E
authors.initials: ME
authors.lastname: Nelson
authors.forename: M A
authors.initials: MA
authors.lastname: Fiatarone
authors.forename: J E
authors.initials: JE
authors.lastname: Layne
authors.forename: I
authors.initials: I
authors.lastname: Trice
authors.forename: C D
authors.initials: CD
authors.lastname: Economos
authors.forename: R A
authors.initials: RA
authors.lastname: Fielding
authors.forename: R
authors.initials: R
authors.lastname: Ma
authors.forename: R N
authors.initials: RN
authors.lastname: Pierson
authors.forename: W J
authors.initials: WJ
authors.lastname: Evans
mesh_terms: D015502:Absorptiometry, Photon; D000368:Aged; D000886:Anthropometry; D001823:Body Composition / Q000502:physiology*; D015992:Body Mass Index; D001835:Body Weight; D003404:Creatinine / Q000652:urine; D017097:Electric Impedance; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D008875:Middle Aged; D009501:Neutron Activation Analysis; D010806:Physical Education and Training; D011865:Radioisotope Dilution Technique; D013848:Thigh / Q000000981:diagnostic imaging; D014057:Tomography, X-Ray Computed; D014316:Tritium
chemical_list: D014316:Tritium; D003404:Creatinine