Objectives: Maintaining lean soft tissue and bone mineral density during early to middle adulthood is important for delaying the effects of sarcopenia and osteopenia later in life. Physical activity high in intensity and volume is associated with optimal bone health. CrossFit® (CF) training combines high-intensity aerobic, resistance, and floor exercises to stimulate physical fitness and health responses. We tested differences in total and regional body composition between adult CF participants and nonactive (NA) adults. Methods: 24 CF trained (at least 3 times/wk for the past 3 months, n=11 women) and 24 NA (exercise no more than 1 time/wk for the past 3 months, n=12 women) adults were measured for body composition by iDXA (Lunar Corporation, Madison, WI). Subjects were further categorized into early (≤29y, mean=24y) and middle (30-49y, mean=37y) adulthood. Results: Linear models testing the main and interactive effects of training group and age group demonstrated no difference (p=0.82) in body weight of CF (77.5kg) and NA (76.6 kg) groups. CF had lower trunk (p< 0.002), android (p=0.001), gynoid (p=0.01), arm (p< 0.003), leg (p< 0.05), and total body (p=0.01) fat mass, lower total body %fat (p=0.002) and greater trunk (p=0.01), arm (p< 0.03), leg (p< 0.02), and total body (p=0.002) lean soft tissue (LST) mass. Younger adults had lower android (p< 0.04) and arm (p< 0.02) fat. CF had greater pelvis (p=0.004), arms (p< 0.01), legs (p< 0.04), spine (p< 0.02), trunk (p< .0009), and total body (p< 0.03) bone mineral density. Conclusions: CF training, typically high in intensity and volume, is associated with beneficial body composition and bone health with few differences between early- and middle-aged adults. CF training maintained through at least middle adulthood may delay the onset of difficulty performing daily activities, falls, and morbidities associated with the effects of sarcopenia and osteopenia. Funding Sources: USDA-Agriculture Research Service.

Increasing the reinforcing value of a stimulus occurs after repeated exposures to the reinforcer via neuroadaptations that increase the incentive salience of the stimulus. Exercise is a reinforcer and increasing exercise reinforcement (RRVex) may be dependent on simultaneously increasing tolerance for exercise intensity. Positive outcome expectancy (POE) of participating in an intervention can be an important determinant of treatment efficacy, such as when attempting to increase tolerance for exercise intensity or RRVex. We hypothesized that (1) high-intensity interval training (HIIT) that produces great discomfort would increase tolerance for exercise intensity, (2) adding a positive outcome expectancy (POE) component to HIIT would further increase tolerance for exercise intensity and, (3) increases in tolerance for exercise discomfort would mediate increases in RRVex. A randomized controlled trial with a factorial design included HIIT + POE (n = 33 adults, n = 19 women) and HIIT-only (n = 33, n = 19 women) groups. Both groups participated in HIIT 3 d/wk for 6 wks. HIIT + POE received POE treatment each exercise session. Outcomes were measured at baseline, after 6 weeks of HIIT, and 4 weeks post-HIIT (10 wk). Changes in the RRVex were assessed by a progressive ratio schedule of reinforcement task. Other outcomes were outcome expectations, tolerance for exercise intensity, and behavior regulations of exercise. Outcome expectancy did not change in either group. Tolerance for exercise discomfort increased (P < .001) above baseline by 12% at 6 wk and 13% at 10 wk. Intrinsic, integrated, and identified behavior regulations of exercise were all increased (P < .01) at 6 wk and remained so at 10 wk. However, RRVex was not changed and change in RRVex was not correlated with change in tolerance for exercise intensity. HIIT increases tolerance for exercise intensity and intrinsic, integrated, and identified behavior regulations of exercise. USDA-ARS.

BACKGROUND:Resting metabolic rate (RMR) measurement is time consuming and requires specialized equipment. Prediction equations provide an easy method to estimate RMR; however, their accuracy likely varies across individuals. Understanding the factors that influence the accuracy of RMR predictions will help to revise existing, or develop new and improved, equations. OBJECTIVE:Our aim was to test the validity of RMR predicted in healthy adults by the Harris-Benedict, World Health Organization, Mifflin-St Jeor, Nelson, Wang equations, and three meta-equations of Sabounchi. DESIGN:Predicted RMR was tested for agreement with indirect calorimetry. PARTICIPANTS/SETTING:Men and women (n=30) age 18 to 65 years from Grand Forks, ND, were recruited and included for analysis during spring/summer 2014. Participants were nonobese or obese (body mass index range=19 to 39) and primarly white. MAIN OUTCOME MEASURE:Agreement between measured (indirect calorimetry) and predicted RMR was measured. STATISTICAL ANALYSIS:The methods of Bland and Altman were employed to determine mean bias (predicted minus measured RMR, kcal/day) and limits of agreement between predicted and measured RMR. Repeated-measures analysis of variance was used to test for bias in RMR predicted from each equation vs the measured RMR. RESULTS:Bias (mean±2 standard deviations) was lowest for the Harris-Benedict (-14±378 kcal/24 h) and World Health Organization (-25±394 kcal/24 h) equations. These equations also predicted RMR that were not different from measured. Mean RMR predictions from all other equations significantly differed from indirect calorimetry. The 2 standard deviation limits of agreement were moderate or large for all equations tested, ranging from 314 to 445 kcal/24 h. Prediction bias was inversely associated with the magnitude of RMR and with fat-free mass. CONCLUSIONS:At the group level, the traditional Harris-Benedict and World Health Organization equations were the most accurate. However, these equations did not perform well at the individual level. As fat-free mass increased, the prediction equations further underestimated RMR.

Background & aims: Determine the accuracy of body density (Db) estimated with upper-body skinfold thickness (SET) measurements compared to air-displacement plethysmography (ADP) and ascertain whether body mass index (BMI) impacts the accuracy of SET to assess Db.Methods: We estimated Db with SET and ADP in 131 healthy men and women with normal (N; 18.5-24.9 kg/m(2)), overweight (OW; 25-29.9 kg/m(2)), and obese (OB; 30-39.9 kg/m(2)) BMI.Results: Compared with ADP, SET overestimated (p < 0.05) Db in OW and OB females and in OB males (-0.0047, -0.0164 and -0.0119 g/cc, respectively), and underestimated (p < 0.05) Db in N females and males (0.0050 and 0.0068 g/cc, respectively) but did not differently estimate Db in OW males. The gender by BMI group interaction was not significant. SET underestimated (p < 0.05; 0.0058 g/cc) Db in the N and overestimated (p < 0.05: 0.0113 g/cc) Db in the OB BMI groups. The error in predicting Db did not change significantly over the range of Db within the N (r = 0.239, p = 0.06) and OB (r = 0.160, p = 0.934) BMI groups. Limits of agreement were -0.0165 to 0.0284 g/cc and -0.0365 to 0.0085 g/cc for the N and OB BMI groups, respectively. The error of estimating Db with SET was correlated with mean Db in the aggregate sample (r = 0.495, p < 0.0001) and the OW group (r = 0.394, p < 0.009). The regression-based limits of agreement were +/-0.0226 g/cc in the total group and +/-0.0168 g/cc in the OW group.Conclusions: Although SET offer practical advantages, the validity of SET to estimate Db among individuals with N and OB BMI is adversely affected. (C) 2009 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism.

Objective: We compared body composition estimates using an eight-electrode, segmental, multiple-frequency bioelectrical impedance analysis (segmental MF-BIA) and dual x-ray absorptiometry (DXA) in a group of healthy adults with a range of body mass indexes (BMIs).Methods: Percentage of body fat (%BF), fat-free mass, and fat mass assessed by DXA and segmental MF-BIA in 132 healthy adults were classified by normal (N; 18.5-24.9 kg/m(2)), overweight (OW; 25-29.9 kg/m(2)), and obese (OB; 30-39.9 kg/m(2)) BMI.Results: Compared with DXA, segmental MF-BIA overestimated %BF in the OB BMI group (3.4%; P < 0.0001). MF-BIA overestimated %BF among men (0.75%; P < 0.006) and women (0.87%; P < 0.006) and underestimated it in the N BMI group (-1.56%; P < 0.0001); %BF was not different between methods in the OW BMI group. Error in %BF determined by segmental MF-BIA and DXA increased as %BF increased (r = 0.42, P < 0.0001). Waist circumference was the only significant predictor of systematic error in %BF between MF-BIA and DXA (r = 0.60, P < 0.0001).Conclusion: Eight-electrode, segmental MF-BIA is a valid method to estimate %BF in adults with BMI classified as N and OW, but not as OB. Estimation of trunk resistance with current segmental MF-BIA devices may explain the underestimation of %BF in the adults with OB BMI. Further examination of the effect of waist circumference and body fat distribution on the accuracy of BIA measurements is warranted. (C) 2009 Elsevier Inc. All rights reserved.

Increases in TBW are typical of pregnancy with advancing gestation. Because excessive TBW expansion can lead to adverse outcomes, a safe non-invasive method for routine assessment of TBW would be useful clinically. BIVA uses resistance (R) and reactance (Xc) determined with 800 μA at 50 kHz and normalized for height (H) to establish a vector with length and position; it has been used to monitor hydration status in hemodialysis patients. To ascertain the validity of BIVA in physiological conditions, we studied 15 women, aged 21-37 y, before, during pregnancy and PP. TBW assessed with D2O dilution and body R and Xc determined with single-frequency tetrapolar BIA were measured regularly. Body weight (61.9±2.3 to 75.5±2.3 kg) and TBW (32.7±1.1 to 39.8±1.1 L) increased (p<0.05) from pre-pregnancy to the 3rd trimester of pregnancy, and decreased (p<0.05; 67.0±2.3 kg and 34.0±1.1 L) PP. R/H and Xc/H decreased (p<0.05; 361±10 to 318±10 and 44±1 to 36±1 Ω/m) during pregnancy and increased (p<0.05; 355±10 and 41±1 Ω/m) PP. Vector length decreased (p<0.05; 363±10 to 320±10 Ω) during pregnancy, and increased PP (p<0.05; 357±10 Ω). Changes in vector length and TBW during pregnancy and PP were correlated (r = - 0.599; p<0.001). These findings indicate that impedance vectors provide quantitative evidence of hydration status during pregnancy, and suggest that the BIVA method is useful in monitoring hydration status in pregnancy.

ADP, using Bod Pod, is a popular method to assess body composition. For valid results, however, the manufacturer warrants tight-fitting clothing (swimsuit or spandex), which may be uncomfortable or impractical for overweight (O) and obese (OB) persons or those with negative body image. This study compared body composition estimates from two alternative clothing schemes, scrubs (SC) and t-shirt/shorts (TS), to spandex (SP), and validity of these estimates to dual x-ray absorptiometry (DXA). Body density (BD) and percent body fat (%BF) by ADP and %BF by DXA were assessed in 132 adults classified by BMI group: normal (N), O, and OB. Interactions between clothing type and BMI group were found for BD (p<.0001) and %BF (p<.0001) by ADP. Compared to DXA %BF (N: 22.39% ± 0.71; O: 29.48% ± 0.72; OB: 35.32% ± 0.73), %BF by ADP was underestimated in SC and TS for N (−11.43 ± 0.42; −8.63 ± 0.42; p<.0001) and O (−6.75 ± 0.43; −4.90 ± 0.43; p<.0001) groups, respectively, but was not different for the OB group (SC: −0.72 ± 0.44; p=.10) (TS: 0.55 ± 0.44; p=.21). %BF from SP was underestimated for N (−2.35 ± 0.42; p<.0001), and overestimated for O (1.19 ± 0.43; p=.006) and OB (4.81 ± 0.44; p<.0001) BMI. SC and TS are not acceptable substitutes for estimating %BF by ADP for N and O BMI group, but may be an alternative when testing OB persons.

Objective: This study tested the hypothesis that bioelectrical impedance vectors, group and individual, are valid indicators of total body water (TBW) and hydration status in women experiencing fluid gain and loss during and after pregnancy.Methods: We measured TBW, assessed with D2O dilution, and resistance (R) and reactance (Xc), determined with 800 mu A at 50 kHz and standardized for height (H) and plotted on a bivariate (R-Xc) graph, in 15 women, 21-37 y of age, longitudinally before and during pregnancy and postpartum (PP).Results: Body weight (61.9 +/- 2.3 to 75.5 +/- 2.3 kg) and TBW (31.4 +/- 1.1 to 38.2 +/- 1.1 L) increased (P < 0.05) from before pregnancy to the third trimester of pregnancy and decreased PP (67.0 +/- 2.3 kg and 32.7 +/- 1.1 L, P < 0.05). R/H and Xc/H decreased during pregnancy (P < 0.05, 361 +/- 10 to 318 +/- 10 and 44 +/- 1 to 36 +/- 1 omega/m, respectively) and increased PP (P < 0.05, 355 +/- 10 and 41 +/- 1 Omega/m). Vector length decreased (P < 0.05, 363 +/- 10 to 320 +/- 10 Omega) during pregnancy and increased PP (P < 0.05, 357 +/- 10 Omega). Changes in vector length and TBW during pregnancy and PP were correlated (r = -0.599, P < 0.001). Women with vectors exceeding a 75% tolerance interval had greater TBW gain (10-12 versus 5-6 L) during pregnancy compared with other women with vectors within this tolerance level.Conclusion: These findings indicate that impedance vectors provide quantitative evidence of hydration status during pregnancy and that the impedance vector method is useful in monitoring hydration status in pregnancy. (c) 2007 Elsevier Inc. All rights reserved.

OBJECTIVE:We determined the effect of clothing type on the validity of air-displacement plethysmography (ADP) to estimate percentage of body fat (%BF) and ascertain if these effects differ by body mass index (BMI). METHODS:The %BF by dual x-ray absorptiometry (DXA) and %BF, density, and body volume by ADP were assessed in 132 healthy adults classified by normal (N; 18.5-24.9 kg/m2), overweight (OW; 25-29.9 kg/m2), and obese (OB; 30-39.9 kg/m2) BMIs. RESULTS:Compared with DXA, ADP underestimated (P < 0.0001) %BF from scrubs (SC) and t-shirt/shorts (TS) in N (11.4%; 8.6%) and OW (6.8%; 4.9%) BMI groups, respectively. ADP compared with DXA overestimated (P < 0.0006) %BF in the OW group (1.2%), but underestimated (P < 0.0001) it in the N group (2.4%). ADP also overestimated (P < 0.006) %BF in the OB group wearing spandex (SP; 4.8%), but not in those wearing SC (0.7%; P = 0.10) and TS (0.5%; P = 0.22) versus DXA. CONCLUSION:All three clothing types showed significant error in estimating %BF with ADP compared with DXA in N and OW BMI. Use of spandex provided the least error and is the preferred attire to obtain valid body composition results when testing N and OW subjects. However, SP provided the greatest error in the OB group. Error in ADP %BF in OB was minimal in SC and TS and similar to the within-subject variability in %BF estimates with ADP. Thus, TS and SC are acceptable alternatives to SP in adults with excess body weight.

Objective: This study tested the hypothesis that supplementation of chromium picolinate (CrPic), 200 mu g Cr/d, compared with an equivalent amount of picolinic acid (1720 mu g) in CrPic and placebo, decreases body weight, alters body composition, and reduces iron status of women fed diets of constant energy and nutrients.Methods: We fed 83 women nutritionally balanced diets, used anthropometry and dual x-ray absorptiometry to assess body composition, and measured serum and urinary Cr and biochemical indicators of iron status before and serially every 4 wk for 12 wk in a double-blind, randomized trial.Results: CrPic supplementation increased (P < 0.0001) serum Cr concentration and urinary Cr excretion compared with picolinic acid and placebo. CrPic did not affect body weight or fat, although all groups lost (P < 0.05) weight and fat; it did not affect fat-free, mineral-free mass or measurements of iron status.Conclusion: Under conditions of controlled energy intake, CrPic supplementation of women did not independently influence body weight or composition or iron status. Thus, claims that supplementation of 200 jig of Cr as CrPic promotes weight loss and body composition changes are not supported. (C) 2007 Elsevier Inc. All rights reserved.

Restricted lesions of the globus pallidus which did not cause aphagia or adipsia or affect open-field behavior in either sex retarded acquisition of two-way avoidance behavior by both male and female rats, but interfered with the development of one-way avoidance only by males. Sex differences in the behavioral effects of pallidal lesions differ from sex differences in the effects of striatal lesions and deficits in avoidance behaviors can be dissociated from impairments in consummatory activity that also may accompany basal ganglia damage.