Body composition is acknowledged as a determinant of athletic health and performance. Its assessment is crucial in evaluating the efficiency of a diet or aspects related to the nutritional status of the athlete. Despite the methods traditionally used to assess body composition, bioelectric impedance analysis (BIA) and bioelectric impedance vector analysis (BIVA) have recently gained attention in sports, as well as in a research context. Only until recently have specific regression equations and reference tolerance ellipses for athletes become available, while specific recommendations for measurement procedures still remain scarce. Therefore, the present narrative review summarizes the current literature regarding body composition analysis, with a special focus on BIA and BIVA. The use of specific technologies and sampling frequencies is described, and recommendations for the assessment of body composition in athletes are provided. Additionally, the estimation of body composition parameters (i.e., quantitative analysis) and the interpretation of the raw bioelectrical data (i.e., qualitative analysis) are examined, highlighting the innovations now available in athletes. Lastly, it should be noted that, up until 2020, the use of BIA and BIVA in athletes failed to provide accurate results due to unspecific equations and references; however, new perspectives are now unfolding for researchers and practitioners. In light of this, BIA and especially BIVA can be utilized to monitor the nutritional status and the seasonal changes in body composition in athletes, as well as provide accurate within- and between-athlete comparisons.

Cunha PM, Nunes JP, Tomeleri CM, Nascimento MA, Schoenfeld BJ, Antunes M, Gobbo LA, Teixeira D, and Cyrino ES. Resistance training performed with single and multiple sets induces similar improvements in muscular strength, muscle mass, muscle quality, and IGF-1 in older women: A randomized controlled trial. J Strength Cond Res 34(4): 1008–1016, 2020—The purpose of this study was to compare the effects between single set vs. multiple sets of resistance training (RT) on measures of muscular strength, muscle mass, muscle quality (MQ), and insulin-like growth factor 1 (IGF-1) in untrained healthy older women. Sixty-two older women were randomly assigned to 1 of the 3 groups: single-set RT (SS, n = 21), multiple-sets RT (MS, n = 20), or nontraining control (CG, n = 21). Both training groups performed RT for 12 weeks, using 8 exercises of 10–15 repetitions maximum for each exercise. The SS group performed only 1 set per exercise, whereas MS performed 3 sets. Anthropometry, muscle strength (1RM tests), lean soft tissue (LST), and MQ from upper limbs (UL) and lower limbs (LL), and IGF-1 were measured before and after training. Both training groups showed significant pre-training to post-training increases for UL1RM (SS: 37.1%, MS: 27.3%, CG: −3.0%), LL1RM (SS: 16.3%, MS: 21.7%, CG: −0.7%), ULLST (SS: 7.8%, MS: 8.8%, CG: −1.1%), LLLST (SS: 5.6%, MS: 6.3%, CG: −0.8%), upper-limb muscle quality (SS: 25.2%, MS: 16.7%, CG: −0.2%), lower-limb muscle quality (SS: 10.5%, MS: 15.4%, CG: −3.5%), and IGF-1 (SS: +7.1%, MS: +10.1%, CG: −2.2%). We conclude that both SS and MS produce similar increases in muscular strength, LST, and MQ of upper and lower limbs, and IGF-1 after 12 weeks of RT in untrained older women. Our results suggest that, in the early stages, the RT regardless number of sets is effective for improving muscular outcomes in this population.

de Freitas, MC, Cholewa, JM, Gobbo, LA, de Oliveira, JVNS, Lira, FS, and Rossi, FE. Acute capsaicin supplementation improves 1,500-m running time-trial performance and rate of perceived exertion in physically active adults. J Strength Cond Res 32(2): 572-577, 2018-The purpose of this study was to investigate the acute effect of capsaicin supplementation on performance, rate of perceived exertion (RPE), and blood lactate concentrations during short-duration running in physically active adults. Ten physically active men (age = 23.5 ± 1.9 years, mass = 78.3 ± 12.4 kg, and height = 177.9 ± 5.9 cm) completed 2 randomized, double-blind trials: Capsaicin condition (12 mg) or a placebo condition. Forty-five minutes after supplement consumption, the participants performed a 1,500-m running time trial. Time (in seconds) was recorded. Blood lactate concentration was analyzed at rest, immediately after exercise, after 5, 10, and 30 minutes during recovery and the RPE was collected after exercise. The time was significantly (t = 3.316, p = 0.009) lower in the capsaicin (371.6 ± 40.8 seconds) compared with placebo (376.7 ± 39 seconds). Rate of perceived exertion was significantly (t = 2.753, p = 0.022) less in the capsaicin (18.0 ± 1.9) compared with the placebo (18.8 ± 1.3). Lactate increased across time for both conditions without significant differences between (p > 0.05). In summary, acute capsaicin supplementation improves middle distance running (1,500 m) performance and reduced RPE in physically active adults.

Background: Low-grade inflammation can be present in chronic obstructive pulmonary disease (COPD), which may affect the regulation of muscle protein and body metabolism. Regular exercise show improvement in muscle strength and dyspnea in patients with COPD, however, the response to training on inflammatory and metabolic disorders is unclear. In this study, we compared the effects of resistance training using weight machines and elastic resistance (bands and tubes) on the inflammatory and metabolic responses in patients with COPD.Methods: Patients with COPD were randomized into three groups: elastic band group (EBG), elastic tube group (ETG), and weight machines equipment group (MG). EBG and ETG were analyzed together [elastic group (EG)]. The participants were evaluated for pulmonary function (spirometry), peripheral muscle strength (digital dynamometry), IL-6, TNF-α, IL-10, IL-15 (Immunoassay), glucose, triacylglycerol, total cholesterol, HDL-c, and albumin levels (Enzymatic colorimetric). Blood samples were collected to assess the acute and chronic exercise responses after 12 weeks of training protocol.Results: The patient's mean age was 71.53 ± 6.97 years old. FEV1 (percent predicted) was 50.69 ± 16.67 and 45.40 ± 15.15% for EG and MG, respectively (p = 0.28). All groups increased muscle strength (p < 0.05) with no differences between groups. The acute response to exercise after 12 weeks of training showed improvement of inflammation when compared to baseline. Regarding the chronic effects, it was observed a decrease of all cytokines, except IL-10 (p < 0.05). After 12 weeks of training, the analysis of the metabolic profile presented a reduction in glucose concentration (p < 0.01), with no differences between groups (p = 0.30) and a decrease in triacylglycerol for the EG (p > 0.01).Conclusions: Training with elastic resistances or conventional weight machines showed improvement of inflammation response after 12 weeks of training. Chronically, both training groups showed anti-inflammatory effects, with the EG showing a strong tendency to improve IL-10/TNF-α ratio and IL-10 levels.Trial registration : RBR-6V9SJJ.

The present systematic review aimed to compare the accuracy of Bioelectrical Impedance Analysis (BIA) and 33 Bioelectrical Impedance Vector Analysis (BIVA) vs. reference methods for the assessment of body composition in 34 athletes. Studies were identified based on a systematic search of internationally electronic databases (PubMed and Scopus) 35and hand searching of the reference lists of the included studies. In total, 42 studies published between 1988 and 2021 36 were included. The methodological quality was assessed using the Quality Assessment Tool for Observational Cohort 37 and Cross-sectional Studies as recommended by the National Institute of Health. Twenty-three studies had an overall 38 good rating in terms of quality, while 13 were rated as fair and six as poor, resulting in a low to moderate risk of bias. Fat 39 mass was inconsistently determined using BIA vs. the reference methods, regardless of the BIA-technology. When using 40 the foot to hand technology with predictive equations for athletes, a good agreement between BIA and the reference 41 methods was observed for fat-free mass, total body, intra and extra cellular water. However, an underestimation in fat-42 free mass and body fluids was found when using generalized predictive equations. Classic and Specific BIVA represented 43 a valid approach for assessing body fluids (Classic BIVA) and percentage of fat mass (Specific BIVA). The present 44 systematic review suggests that BIA and BIVA can be used for assessing body composition in athletes, provided that 45 foot-to-hand technology, predictive equations, and BIVA references for athletes are used.

Our findings suggest that healthy elderly women with higher values of PhA have a better muscle quality and functionality, regardless of age and body composition.

The main purpose of the present study was to investigate the effect of a hypertrophy-type resistance training protocol on phase angle, an indicator of cellular integrity, in young adult men and women. 28 men (22.2±4.3 years, 67.8±9.0 kg and 174.2±6.8 cm) and 31 women (23.2±4.1 years, 58.7±12.1 kg and 162.7±6.4 cm) underwent a progressive RT for 16 weeks (2 phases, 8 weeks each), 3 times per week, consisting of 10 to 12 whole body exercises with 3 sets of 8-12 repetitions maximum. Phase angle, resistance, reactance and total body water (intra and extracellular water compartments) were assessed by bioimpedance spectroscopy (Xitron 4200 Bioimpedance Spectrum Analyzer). Total body water, intracellular water and phase angle increased significantly (<0.05) in men (7.8, 8.3, and 4.3%, respectively) and women (7.6, 11.7, and 5.8% respectively), with no significant difference between sexes (>0.05). Bioimpedance resistance decreased (<0.05) similarly in both sex (men=-4.8%, women=-3.8%). The results suggest that regardless of sex, progressive RT induces an increase in phase angle and a rise in cellular hydration.

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