Background/objective: Several articles have described body composition in anorexia nervosa, whereas little is known about this issue in underweight ballet dancers and constitutionally lean females. The main aim of this study was to assess whether phase angle (a bioimpedance variable related to body cell mass) differs according to the type of underweight in female adolescents and young women. Subjects/methods: Skinfold thicknesses and bioimpedance analysis (whole body and limbs) were evaluated in three groups of underweight patients (30 patients with anorexia nervosa, 10 constitutionally lean individuals and 15 classical dancers) and 30 normal weight controls. Results: There were no differences between the three groups of underweight patients with respect to anthropometric and bioelectrical impedance analysis (BIA) variables with the exception of phase angle. The latter was significantly higher in dancers, lower in anorectic patients and not different in constitutionally lean patients, as compared with controls. Conclusions: Phase angle (assessed by single-frequency BIA) appears to discriminate between different forms of underweight, being an effective marker of qualitative changes in body composition.

Objective: To assess body composition changes occurring in female anorectic patients after complete weight recovery. Design: Longitudinal study. Subjects: Ten female patients with anorexia nervosa (age at baseline: 19.7 AE 5.8 y) were studied both when undernourished (body mass index, BMI 14.8 AE Interventions: Fat mass and fat-free mass were determined by dual-energy X-ray absorptiometry. Skinfold thicknesses and circumferences were also measured. Arm muscle area and arm fat area were calculated by standard formulas. Results: The undernourished patients had lower fat-free mass, fat mass, skinfold thicknesses and circumferences. After refeeding, fat mass represented 25 -71% (mean 56%) of the mass regained, this percentage being directly related to the extent of weight gain. The increases in skinfolds and circumferences depended upon the site considered and were correlated to a various extent with those in weight or BMI. Skinfolds at biceps and abdominal sites and the waist-to-hip ratio remained significantly higher, whereas arm muscle circumference was significantly lower, in the refed group than in the control one. Conclusion: The percentage of fat in the weight regained by refed female anorectic patients was directly related to the extent of body mass increase. Refed anorectic patients appear to preferentially regain fat in the abdominal and triceps regions. Abnormalities in skinfolds (at biceps and abdominal sites), arm muscle area and waist-to-hip ratio still persist in refed anorectic patients in comparison to control healthy controls.

). MEASUREMENTS: Impedance and phase angle were determined for the whole body (13 patients) and separately for arms and legs (10 patients). RESULTS: Bioimpedance index (height 2 aimpedance) and phase angle were lower in the undernourished group. Whole-body impedance declined (median, min-max) by 45, 1-151 Ohm after refeeding; the variations of bioimpedance index (BI-Index) were weakly correlated (P`0.10) with BMI changes. Limb phase angles increased with refeeding, but only changes in whole-body phase angle were correlated (P`0.025) with the corresponding variations of Wt or BMI. CONCLUSION: Whole-body phase angle increased after weight recovery of anorexic patients, suggesting the occurence of modi®cations in the extracellular-to-intracellular water ratio. These changes were proportional to the increase in BMI and Wt.

Total body water (TBW) was measured by deuterium oxide (DzO) dilution and predicted from bioelectrical impedance (Z) gave a more accurate prediction of TBW by bioelectrical impedance analysis on the study subjects, with biases of -0.1 (SD 1.8) and 0.5 (SD 1.7) litres in controls and patients respectively (NS). However, the individual bias was sometimes high. It is concluded that bioelectrical impedance analysis can be used to predict TBW in anorexic women at a population level, but the predictions are less good than those based on body weight alone.

Bioelectrical impedance analysis has been widely used in the clinical and sport areas because it is a safe, non-invasive, rapid and inexpensive technique that evaluates some electrical properties of the body, such as resistance (R), reactance (X c ) and phase angle (PhA). The aim of this study is to evaluate body composition changes in professional cyclists, participating at the Giro D'Italia 2012, a three week stage race, and in particular PhA modifications as an expression of fat free mass nutritional status. Data were collected at the beginning, in the middle and at the end of the competition. Body weight, circumferences, skinfold thickness and BIA variables (total and segmental body) were measured. Body composition, measured by skinfold thickness, changed during the competition: fat free mass increased, but not significantly, in the middle and at the end of the competition, whereas fat mass significantly decreased versus the baseline in the middle and at the end of the competition. The total PhA did not significantly change in the middle of the competition but was significantly reduced at the end. The arm PhA did not change significantly at both times of the competition, whereas a significant reduction was reported for leg PhA in the middle and at the end of the competition. These results suggest the use of bioimpedance analysis, in particular PhA measurement, to monitor athletes' fat free mass characteristics during medium- and long-term competitions.