Aryanne Hydeko Fukuoka

This study aimed to verify the relationship between changes in thigh muscle‐localized bioelectrical impedance analysis (ML‐BIA) parameters and performance in a multiple‐set exercise. The sample consisted of 30 female university students (22.1 ± 3.2 years). The ML‐BIA parameters, including localized muscle resistance (ML‐R), reactance (ML‐Xc), and phase angle (ML‐AngF), were evaluated using a tetrapolar bioelectric impedance device operating at a frequency of 50 KHz. The multiple sets protocol was performed with an isokinetic dynamometer. For body composition, total and leg lean soft tissue (LST) were evaluated using dual X‐ray absortiometry. Student's t‐test for paired samples was used to compare the ML‐BIA parameters and thigh circumference pre and postexercise. Linear regression analysis was performed to verify the ∆ML‐PhA as a predictor of peak torque for the three sets alone while controlling for total and leg LST. There were differences in the ML‐R (∆ = 0.02 ± 1.45 Ω; p = 0.001; and E.S = 0.19), ML‐Xc (∆ = 2.90 ± 4.12 Ω; p = 0.043; and E.S = 0.36), and thigh circumference (∆ = 0.82 ± 0.60 cm; p < 0.001; and E.S = 0.16) pre‐ and post‐multiple sets. ΔML‐PhA was a predictor of performance in the first set (p = 0.002), regardless of total and leg LST. However, the ΔML‐PhA lost its explanatory power in the other sets (second and third), and the variables that best explained performance were total and leg LST. The ML‐BIA (ML‐R and ML‐Xc) parameters were sensitive and changed after the multiple sets protocol, and the ΔML‐PhA was a predictor of performance in the first set regardless of the total and leg LST.

Objective . This study aimed to investigate the capacity of the bioelectrical muscle localized phase angle (ML-PhA) as an indicator of muscle power and strength compared to whole body PhA (WB-PhA). Approach . This study assessed 30 young women (22.1 ± 3.2 years) for muscle power and strength using the Wingate test and isokinetic dynamometer, respectively. Bioimpedance analysis at 50 kHz was employed to assess WB-PhA and ML-PhA. Lean soft tissue (LST) and fat mass (FM) were quantified using dual x-ray absorptiometry. Performance values were stratified into tertiles for comparisons. Regression and mediation analysis were used to test WB-PhA and ML-PhA as performance predictors. Main results . Women in the second tertile of maximum muscle power demonstrated higher ML-PhA values than those in first tertile (13.6° ± 1.5° versus 11.5° ± 1.5°, p = 0.031). WB-PhA was a predictor of maximum muscle power even after adjusting for LST and FM ( β = 0.40, p = 0.039). ML-PhA alone predicted average muscle power ( β = 0.47, p = 0.008). FM percentage was negatively related to ML-PhA and average muscle power, and it mediated their relationship ( b = 0.14; bias-corrected and accelerated 95% confidence interval: 0.007–0.269). Significance . PhA values among tertiles demonstrated no differences and no correlation for strength variables. The results revealed that both WB and ML-PhA may be markers of muscle power in active young women.

This study aimed to compare muscle strength and power indicators according to bioimpedance spectroscopy’s phase angle (PhA) values, in resistance-trained (RT) men, while exploring associations between PhA and performance. Forty-four men aged 18–45 years, engaged in RT, were allocated according to PhA tertiles. Lean soft tissue (LST) and fat mass (%FM) were assessed using dual-energy x-ray absorptiometry; dynamic muscle strength using 1 repetition maximum (1RM) of bench press (BP) and back squat (BS) and muscle power using Wingate test (WT) and countermovement jump (CMJ). For WT and CMJ, the 3rd tertile was significantly higher than the 1st tertile (p = 0.027 and p = 0.018, respectively). Regarding BP 1RM, the 3rd tertile was significantly higher than the 2^nd tertile (p = 0.037). LST better explained the variability in the WT, BS and BP (p =< 0.001), while %FM better accounted for jump height in CMJ (p =< 0.001). PhA was a predictor of performance in both CMJ (p = 0.040) and BP (p = 0.012), independently of LST and %FM. Participants with higher PhA also displayed superior muscle strength of the upper limbs and greater muscle power of the lower limbs. PhA displayed significant moderate associations with performance in CMJ and BP, even after controlling for body composition. Still, LST was the most important predictor of muscle strength and power.

Procurando entender o declínio da atividade física objetivou-se identificar as barreiras e facilitadores para a prática de atividade física em estudantes de 11 a 16 anos da Região Sudeste do Estado de São Paulo e do Norte Pioneiro do Paraná. A amostra foi composta por 121 estudantes de escolas públicas e privadas. Para investigar as barreiras e os facilitadores foi utilizado um questionário de estilo de vida adaptado para brasileiros, de forma online, pela plataforma do Google Docs, composto por 25 perguntas fechadas. Os dados foram tabulados e analisados por meio do Statistical Package for the Social Science (SPSS), versão 26.0 e foi aplicado o Teste Qui-quadrado de Pearson. Os principais resultados foram: o principal facilitador para a prática de atividade física foi o incentivo da família. A falta de orientação profissional, apesar de não trazer um resultado estatisticamente significativo, apresentou valores expressivos (G - 11 a 14: 45,9%; G - 15 a 16: 40%). Já a falta de companhia, para o grupo G - 15 a 16 anos, se mostrou uma barreira, trazendo valor estatístico significativo (p=0,028).