beginning the study. Figure 1 —Experimental design. VITD = 5,000 IU of vitamin D 3 ; PTH = parathyroid hormone; fT = free testosterone; tT = total testosterone; SHBG = sex hormone-binding globulin; IGF-1 = insulin-like growth factor 1; DXA = dual-energy X-ray absorptiometry. Participants Male and female
Michelle S. Rockwell, Madlyn I. Frisard, Janet W. Rankin, Jennifer S. Zabinsky, Ryan P. Mcmillan, Wen You, Kevin P. Davy and Matthew W. Hulver
Xiaomin Sun, Zhen-Bo Cao, Kumpei Tanisawa, Satomi Oshima and Mitsuru Higuchi
coefficient of variation for the cross-sectional area at the umbilical level was 0.4%. Dual-energy X-ray absorptiometry (DXA; Hologic QDT-4500, DXA Scanner; Hologic Inc., Waltham, MA) was used to measure the body fat percentage. The fat-free mass was calculated from the body weight and body fat percentage
Monica Klungland Torstveit, Ida Fahrenholtz, Thomas B. Stenqvist, Øystein Sylta and Anna Melin
squared in meter (kg/m). Body composition was measured using dual-energy X-ray absorptiometry (Lunar Prodigy, EnCore v. 15; GE Medical Systems, Madison, WI). All measurements were completed in a fasted state between 06:00 and 09:00 a.m. Maximal Oxygen Uptake VO 2max was predicted by asking the subjects
Michael J. Ormsbee, Brandon D. Willingham, Tasha Marchant, Teresa L. Binkley, Bonny L. Specker and Matthew D. Vukovich
urine samples, body composition via dual-energy X-ray absorptiometry, a graded treadmill test to measure peak aerobic capacity (VO 2 peak), and a one-repetition maximum (1-RM) test to measure dynamic strength. Following baseline measurements, study participants were matched for strength and randomly
Nicole Gero, Jacque Cole, Jill Kanaley, Marjolein van der Meulen and Tamara Scerpella
This longitudinal study evaluates the role of impact activity in bone accrual in premenarcheal girls. Twenty-eight gymnasts and 20 controls underwent 1-year analysis; fifteen gymnasts and 8 controls underwent 2-year analysis. Bone mineral density (BMD) was measured yearly by dual energy X-ray absorptiometry. For the 1-year analysis, BMD accrual rates were greater in gymnasts than controls at the forearm only (p < .05). For the 2-year analysis, gains in BMD were 1.5 to 1.9 times greater at the forearm, total hip, and femoral neck for gymnasts (p < .05). These findings confirm the positive effect of impact activity on bone accrual in premenarcheal girls.
David A. Greene, Geraldine A. Naughton, Julie N. Briody, Allan Kemp, Helen Woodhead and Nathalie Farpour-Lambert
This study compared tibial bone and muscle geometry and total body and regional bone mineral content (BMC) in elite female adolescent middle-distance runners (n = 20, age: 16 ± 1.7 years) and age- and sex-matched controls (n = 20, 16 ± 1.8 years) using magnetic resonance imaging and dual-energy X-ray absorptiometry. Significant advantages were found in athletes compared with controls in bone and muscle geometric values for distal tibial cortical, medullary cavity, distal tibial total muscle and dorsi flexor muscle compartment cross-sectional area, and regional BMC. Results imply mechanical loads associated with middle-distance running might be beneficial to musculoskeletal health in adolescent females.
Bernadette L. Foster, Jeff W. Walkley and Viviene A. Temple
The purpose of this study was to describe and compare the bone mineral density of women with intellectual disability (WID) and a comparison group (WOID) matched for age and sex. One hundred and five women, ages 21 to 39, M = 29, were tested for their bone mineral density levels at the lumbar spine and three sites of the proximal femur using dual energy X-ray absorptiometry. No significant difference between groups existed (λ = 0.94, F(4, 98) = 1.68, p = .16, η2 = .06); however, one-sample t tests revealed that bone mineral density for the WID group (n = 35) was significantly lower than zero at the Ward’s triangle (p < .01) and the lumbar spine (p < .05). Approximately one-quarter of WID had low bone density at these two sites, suggesting that WID may be at risk of osteoporotic fracture as they age.
Christie L. Ward, Rudy J. Valentine and Ellen M. Evans
Adiposity, lean mass, and physical activity (PA) are known to influence physical function in older adults, although the independent influences are not completely characterized. Older adults (N = 156, M age = 68.9 ± 6.7 yr, 85 men) were assessed for body composition via dual-energy X-ray absorptiometry, PA by accelerometer, and physical function via timed up-and-go (UP&GO), 30-s chair stand, 6-min walk (6-min WALK), and Star-Excursion Balance Test. In the absence of percentage-body-fat by PA interactions (p > .05), main effects existed such that a higher percentage body fat was associated with poorer performance in UP&GO, 30-s chair stand, and 6-min WALK (p < .05). No significant main effects were found for PA and functional performance. Adiposity explains 4.6–11.4% in physical functional variance (p < .05). Preventing increases in adiposity with age may help older adults maintain functional independence.
Cédric R.H. Lamboley, Donald Royer and Isabelle J. Dionne
The aim of this study was to determine the effects of oral β-hydroxy-β-methylbutyrate (HMB) supplementation (3 g/d) on selected components of aerobic performance and body composition of active college students. Subjects were randomly assigned to either an HMB (n = 8) or a placebo (PLA) group (n = 8) for a 5-wk supplementation period during which they underwent interval training 3 times a week on a treadmill. Aerobic-performance components were measured using a respiratory-gas analyzer. Body composition was determined using dual-energy X-ray absorptiometry. After the intervention, there were significant differences (P < 0.05) between the 2 groups in gains in maximal oxygen consumption (+8.4% for PLA and +15.5% for HMB) and in respiratory-compensation point (+8.6% for PLA and +13.4% for HMB). Regarding body composition, there were no significant differences. The authors concluded that HMB supplementation positively affects selected components of aerobic performance in active college students.
Jennifer Gornall and Rudolph G. Villani
The primary aim was to investigate whether the reduction in resting metabolic rate (RMR) and fat free mass (FFM) associated with a short-term very low kilojoule diet (VLKD) is altered by concurrent resistance exercise. Twenty overweight, premenopausal women were pair matched on body surface area and randomly assigned to either diet only (3,400 kJ/day) or diet combined with resistance training. Before and after 4 weeks of treatment, RMR was assessed by indirect calorimetry; total body mass (TBM), FFM, and fat mass (FM) by dual energy x-ray absorptiometry; total body water (TBW) by bioelectrical impedance; and strength by a weight-lifting test. Both groups had significantly lower TBM, FFM, FM, TBW, absolute RMR, and RMR, with FFM as the covariate, in the posttests than the pretests with no significant differences between groups. It was concluded that 4 weeks of resistance training did not prevent or reduce the decline in FFM and RMR observed with a VLKD.