Purpose: To analyze the association between body fluid changes evaluated by bioelectrical impedance vector analysis and dilution techniques over a competitive season in athletes. Methods: A total of 58 athletes of both sexes (men: age 18.7 [4.0] y and women: age 19.2 [6.0] y) engaging in different sports were evaluated at the beginning (pre) and 6 months after (post) the competitive season. Deuterium dilution and bromide dilution were used as the criterion methods to assess total body water (TBW) and extracellular water (ECW), respectively; intracellular water (ICW) was calculated as TBW–ECW. Bioelectrical resistance and reactance were obtained with a phase-sensitive 50-kHz bioelectrical impedance analysis device; bioelectrical impedance vector analysis was applied. Dual-energy X-ray absorptiometry was used to assess fat mass and fat-free mass. The athletes were empirically classified considering TBW change (pre–post, increase or decrease) according to sex. Results: Significant mean vector displacements in the postgroups were observed in both sexes. Specifically, reductions in vector length (Z/H) were associated with increases in TBW and ICW (r = −.718, P < .01; r = −.630, P < .01, respectively) and decreases in ECW:ICW ratio (r = .344, P < .05), even after adjusting for age, height, and sex. Phase-angle variations were positively associated with TBW and ICW (r = .458, P < .01; r = .564, P < .01, respectively) and negatively associated with ECW:ICW (r = −.436, P < .01). Phase angle significantly increased in all the postgroups except in women in whom TBW decreased. Conclusions: The results suggest that bioelectrical impedance vector analysis is a suitable method to obtain a qualitative indication of body fluid changes during a competitive season in athletes.
Francesco Campa, Catarina N. Matias, Elisabetta Marini, Steven B. Heymsfield, Stefania Toselli, Luís B. Sardinha and Analiza M. Silva
Nuno M. Pimenta, Helena Santa-Clara, Xavier Melo, Helena Cortez-Pinto, José Silva-Nunes and Luís B. Sardinha
Central accumulation and distribution of body fat (BF) is an important cardiometabolic risk factor. Waist-to-hip ratio (WHR), commonly elevated in nonalcoholic fatty liver disease (NAFLD) patients, has been endorsed as a risk related marker of central BF content and distribution, but no standardized waist circumference measurement protocol (WCmp) has been proposed. We aimed to investigate whether using different WCmp affects the strength of association between WHR and BF content and distribution in NAFLD patients. BF was assessed with dual energy X-ray absorptiometry (DXA) in 28 NAFLD patients (19 males, 51 ± 13 years, and 9 females, 47 ± 13 years). Waist circumference (WC) was measured using four different WCmp (WC1: minimal waist; WC2: iliac crest; WC3: mid-distance between iliac crest and lowest rib; WC4: at the umbilicus) and WHR was calculated accordingly (WHR1, WHR2, WHR3 and WHR4, respectively). High WHR was found in up to 84.6% of subjects, depending on the WHR considered. With the exception of WHR1, all WHR correlated well with abdominal BF (r = .47 for WHR1; r = .59 for WHR2 and WHR3; r = .58 for WHR4) and BF distribution (r = .45 for WHR1; r = .56 for WHR2 and WHR3; r = .51 for WHR4), controlling for age, sex and body mass index (BMI). WHR2 and WHR3 diagnosed exactly the same prevalence of high WHR (76.9%). The present study confirms the strong relation between WHR and central BF, regardless of WCmp used, in NAFLD patients. WHR2 and WHR3 seemed preferable for use in clinical practice, interchangeably, for the diagnosis of high WHR in NAFLD patients.
Alex S. Ribeiro, Rafael Deminice, Brad J. Schoenfeld, Crisieli M. Tomeleri, Camila S. Padilha, Danielle Venturini, Décio S. Barbosa, Luís B. Sardinha and Edilson S. Cyrino
The purpose of this study was to investigate the effect of two different resistance training (RT) systems on oxidative stress biomarkers in older women. Fifty-nine older women (67.9 ± 5.0 years) were randomly assigned to one of three groups. Two training groups performed an 8 week RT program either in traditional (TD, n = 20) or a pyramid (PR, n = 20) system 3 times per week, or a control group (CG, n = 19). The TD program consisted of 3 sets of 8–12 RM with constant load for the 3 sets, whereas the PR training consisted of 3 sets of 12/10/8 RM with incremental loads for each set. As compared with the CG, both TD and PR achieved upregulation of the antioxidant system as evidenced by higher (p < .05) values of total radical-trapping antioxidant parameter plasma concentration after intervention (TD= 930.4 ± 160.0 µmolTrolox, PR= 977.8 ± 145.2 µmolTrolox, CG= 794.4 ± 130.2 µmolTrolox). For the protein oxidation adducts, TD and PR presented lower (p < .05) scores compared with CG (TD= 91.2 ± 25.0 µmol/L, PR= 93.0 ± 30.3 µmol/L, CG= 111.0 ± 20.4 µmol/L). However, there were no differences (p < .05) between trained groups in the antioxidant capacity markers and in the protein oxidation adducts markers. The results suggest that 8 weeks of progressive RT promotes an improvement in markers of oxidative stress in older women independent of the load-management RT system.