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.

Background and purpose: There is a growing body of evidence indicating that phase angle (PhA) can be used as an indicator of nutritional status, disease prognosis, and mortality risk; however, it is still unknown whether PhA can be used as an explanator of functional capacity and muscle quality in older women. The main purpose of this cross-sectional study was to explore whether PhA is associated with muscle quality and functional capacity in older women, regardless of total and regional body composition. Methods: A total of 125 older women—66.7 (4.7) years; 65.6 (10.9) kg body mass; 156.1 (5.2) cm height; 26.9 (4.0) kg/m² body mass index—participated in this study. Anthropometric, PhA, body composition (whole-body dual-energy x-ray absorptiometry) and muscle quality (defined as total muscular strength per kilogram of appendicular lean soft tissue) were measured. The functional capacity was assessed by 4 tests: 10-m walk test, rising from sitting position, rising from ventral decubitus position, and rising from a chair and walking around the house. The summing z-scores for the 4 tests was used as a continuous functional capacity score. Linear regression analysis was conducted to test whether PhA is related to the dependent variables (muscle quality and functional capacity), after adjusting for potential covariates. Results: The PhA presented a small-to-moderate relationship with muscle quality (r = 0.27; P < .01) and functional capacity (r = 0.31; P < .01), respectively. These relationships remained significant after adjustment for age, lower limb lean soft tissue, and total fat mass for muscle quality (β= 0.55; P < .01) and functional capacity (β= 1.38; P < .01). Conclusion: 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.