BIA-assessed cellular hydration and muscle performance in youth, adults, and older adults

Nutritional physiology and body composition changes during a rapid ascent to high altitude

Exposure to high altitude might cause the body to adapt with negative energy and fluid balance that compromise body composition and physical performance. In this field study involving 12 healthy adults, sex-balanced, and aged 29 ± 4 years with a body mass index of 21.6 ± 1.8 kg/m2, we investigated the effects of a 4-day trekking up to 4556 m a.s.l. on Monte Rosa (Alps, Italy). The food intake was recorded using food diaries and nutrient averages were calculated. The bio-impedance analysis was performed at low and high altitudes, and a wearable biosensor (Swemax) was used to track hydro-saline losses in two participants. Daily total energy intake was 3348 ± 386 kcal for males and 2804 ± 415 kcal for females (13%-14% protein, 35% fat, 44%-46% carbohydrates). Although there was a significant body weight loss (65.0 ± 9.3 vs. 64.2 ± 9.10 kg, p < 0.001, d = 1.398), no significant changes in body composition parameter were found but a trend in the increase of the bioelectrical phase angle in males (p = 0.059, d = -0.991). Body water percentage significantly changed (p = 0.026, η2 p = 0.440), but the absolute water did not, suggesting that the weight loss was not due to water loss. Salivary and urinary osmolality did not change. A reduction in sweat rate at higher altitudes was observed in both participants. Interestingly, salivary leptin increased (p = 0.014, η2 p = 0.510), and salivary ghrelin decreased (p = 0.036, η2 p  = 0.403). Therefore, the 4-day trekking at altitude of hypoxia exposure induced changes in satiety and appetite hormones. High altitude expeditions require more specific nutritional guidance, and using multiplex analysis could help in monitoring fluid balance and body composition.

Association between ICW/TBW ratio and cancer prognosis: Subanalysis of a population-based retrospective multicenter study

BACKGROUND & AIMS

Disease burden is known to alter cellular integrity and water balance. Therefore, the intracellular water/total body water (ICW/TBW) ratio is used as an adjunctive indicator to predict disease severity and prognosis. The ICW/TBW ratio of patients with cancer, who typically present with low muscle mass, poor nutritional status, and high inflammatory response, reportedly differs from that of the healthy population. Herein, we aimed to evaluate the effect of the ICW/TBW ratio on the prognosis of different subgroups of patients with cancer.

METHODS

This multicenter cohort study included 2787 patients with malignancies between June 2014 and December 2018. The association between covariates and overall survival (OS) was assessed using restricted cubic spline models. The multivariate Cox regression model included variables demonstrating a statistical significance in the univariate Cox regression analysis (P < 0.05) without multicollinearity. The generated nomogram used the C-index and calibration curves to validate the predictive accuracy of the scoring system.

RESULTS

The optimal cut-off value for the ICW/TBW ratio was 0.61. The ICW/TBW ratio was an independent prognostic factor (hazard ratio [HR]: 0.621; 95 % confidence interval [CI]: 0.537-0.719, P < 0.001). Moreover, the ICW/TBW ratio had a greater impact on the prognosis of patients receiving chemoradiotherapy than on those receiving chemotherapy alone (chemoradiotherapy: HR = 0.495, P = 0.005 vs. chemotherapy: HR = 0.646, P < 0.001). Multivariate Cox regression analysis showed that sex, age, tumor stage, body mass index, neutrophil-to-lymphocyte ratio (NLR), and ICW/TBW ratio were associated with OS. Subsequently, a nomogram was developed incorporating these variables and yielded a C-index of 0.743.

CONCLUSIONS

The ICW/TBW ratio was associated with muscle mass, nutritional status, and inflammation. A low ICW/TBW ratio is an independent risk factor for poor prognosis in patients with cancer, especially when they are female, have advanced cancer stage, have sarcopenia, and are receiving radiotherapy.

Musculoskeletal fitness: relative handgrip strength and vertical jump power from 10 to 18 years old

Background

There is an increasing consensus on the relevance of musculoskeletal fitness for health throughout the life cycle, requiring evaluation approaches and description of results capable of characterizing different age groups and body sizes. This study aimed to describe the musculoskeletal fitness of young Portuguese people aged 10-18 through handgrip strength (HGS) and vertical jump power (VJP) and investigate differences between the sexes.

Methods

The sample included 736 participants (359 girls recruited from schools. HGS (kg) was assessed using a handheld dynamometer, and VJP (W) was assessed using a force platform; both measurements were standardized for body mass.

Results

Higher HGS and VJP were observed in boys than in girls from 13 years old (13 years: p ≤ 0.05; 14-18 years: p ≤ 0.001), with no significant differences before this age. The percentile distributions of HGS and VJP are described for each sex using the lambda, mu, sigma (LMS) method. The pattern of development of these variables as a function of age is presented.

Conclusions

Handgrip strength and vertical jump power show differences between the sexes from 13 years of age and similar trajectories to populations in other countries in the same age group.

Limb-specific isometric and isokinetic strength in adults: The potential role of regional bioelectrical impedance analysis-derived phase angle

BACKGROUND & AIMS

It is not yet known whether regional bioelectrical impedance (BIA) phase angle (PhA) may be informative of different types of strength performed by the lower and upper limbs, independently of lean soft tissue mass (LSTM). Using a sample of healthy adults, we aimed to examine the association and relevance of regional PhA relative to isometric and isokinetic strength of each limb.

METHODS

A total of 57 participants (32.7 ± 12.9 years; 24.7 ± 3.5 kg/m2) were included in the present investigation. Regional raw BIA variables were determined using a phase-sensitive BIA device. Dual-energy X-ray absorptiometry was used to evaluate LSTM. Absolute isometric and isokinetic (i.e., 60°/s and 180°/s) strength of each limb (extension and flexion) was assessed using an isokinetic dynamometer and used to calculate relative strength.

RESULTS

In absolute strength, only dominant leg PhA was associated with isometric extension strength (β = 0.283) and isokinetic 180°/s flexion strength (β = 0.354), regardless of LSTM (p < 0.05). In relative strength, a significant association of regional PhA was found for dominant arm flexion isometric strength (β = 0.336), and non-dominant arm and dominant leg extension isometric strength (β = 0.377, β = 0.565, respectively; p < 0.05), independently of LSTM. Similarly, for isokinetic 180°/s strength, regional PhA significantly explained the variance in the relative strength of both arms and dominant leg (β = 0.350 to 0.506), regardless of LSTM (p < 0.05). Relative isokinetic 60°/s strength was not consistently associated with regional PhA (p ≥ 0.05).

CONCLUSIONS

Regional PhA significantly explained relative (isometric and 180°/s isokinetic strength of both arms and dominant leg), but not absolute muscle strength, independently of regional LSTM. Thus, after accounting for body size, regional PhA seems to have its own characteristics that explain relative strength independently of LSTM.

Is muscle localized phase angle an indicator of muscle power and strength in young women?

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.

Bioelectrical, Anthropometric, and Hematological Analysis to Assess Body Fluids and Muscle Changes in Elite Cyclists during the Giro d’Italia

This study aimed to characterize and monitor the body fluid and muscle changes during the Giro d’Italia in nine elite cyclists via bioelectrical (whole-body and muscle-localized) anthropometric and hematological analysis. There were three checkpoint assessments: at the beginning, middle, and end of the race. The Wilcoxon signed-rank test was used to compare the data at baseline and follow up. The Spearman correlation was used to explore relationships between variables. Hotelling’s T2 test was used to determine bioelectrical differences in the complex vector. Bodyweight did not change during the competition, despite bioelectrical and hematological data indicating that at the first half of the race, there was a fluid gain, and in the second half a fluid loss occurred, reaching baseline values. These changes were especially prevalent in the extracellular water compartment. Significant correlations between whole-body bioelectrical vector changes and red blood cell parameter changes were reported. The muscle group most sensitive to changes were the calves. Quadriceps, hamstrings, and calves reported a PhA decrease trend during the first half of the race, and an increase during the second half. Bioelectrical impedance vector analysis appears to be sensitive enough to detect hydration and cellular integrity adaptions induced by competitions as demanding as the Giro d’Italia.

INFLUENCE OF DOUBLE JUMP ROPES ON ATHLETES’ LOWER LIMBS

ABSTRACT Introduction: The double jump rope swing is a rope jumping technique that combines the technology of vertical jump and rope swing, requiring participants to jump twice in a row with the soles of their feet. Objective: Study the effect of double-balance jump rope training on athletes’ muscular strength in the lower limbs. Methods: Through the experimental process, the dynamic and kinematic parameters generated during the process of vertical jump of the participants before and after the double balance rope jump exercise were tested; the effects of double balance rope jump on the biomechanical characteristics of the lower limbs and hip, knee and ankle joints of the participants were analyzed. Results: Compared to pre-training, subjects in the experimental group improved significantly (p = 0.05). Conclusion: After double rope jump training, the subjects obtained an increase in lower limb strength and ground reaction force at the extension stage in the vertical jump. They produced greater force in less time, suggesting that the lower limb burst strength was enhanced. Level of evidence II; Therapeutic studies - investigation of treatment outcomes.

Bioelectrical Impedance Analysis-Derived Phase Angle and Body Composition Are Predictors of Health-Related Fitness in Children and Adolescents with Obesity

There is little evidence in children and adolescents with obesity of the relationships between muscle strength/cardiorespiratory fitness (both components of health-related fitness = HRF) and body composition. Body composition and HRF were studied in 281 children and adolescents with obesity to explore their mutual relationship and to identify the predictors of HRF. By performing a bioelectrical impedance analysis (BIA), the fat-free mass (FFM) and percentage of body fat (%BF) were calculated, and the phase angle (PhA) was recorded. Handgrip strength (HGS), the standard broad jump (SBJ), and five broad jumps (FIVEBJ) were considered for the assessment of muscle strength, and the six-minute walking distance (SIXMWD) for cardiorespiratory fitness. The BMI Z-score was slightly higher in boys, and the %BF was higher in girls, with no difference in the FFM. HGS, the SBJ, and FIVEBJ were greater in the male sex. After controlling for sex, HGS was associated with the FFM, and with height, weight, and absolute BMI. On the contrary, the SBJ and FIVEBJ were negatively associated with adiposity, with a weak relationship with the FFM. The SIXMWD was only poorly related to height, the BMI Z-score, and the waist-to-height ratio. These results were confirmed with a multiple regression analysis. HGS, the SBJ, and FIVEBJ were higher in the first compared to the third tertile of the PhA in both sexes. The PhA also remained a consistent predictor of HGS, the SBJ, and FIVEBJ in a multiple regression analysis. In conclusion, the following predictors have been identified for HRF: the FFM for the isometric strength of the upper limbs and adiposity indicators for the SBJ and FIVEBJ. The PhA emerged as a proxy index of muscle strength.

Dietary Habits Are Related to Phase Angle in Male Patients with Non-Small-Cell Lung Cancer

Introduction: Lung cancer constitutes the most common cause of cancer death. Phase angle (PhA) has been related to lung cancer prognosis, which implies that the identification of dietary or other factors that could predict or modify PhA may have beneficial effects. Νutritional interventions have been linked with positive changes in PhA in certain types of cancer. Aim: The present study aimed to investigate the relationships between dietary habits/nutrition and PhA in NSCLC patients. Methods: The sample consisted of 82 male patients with non-small-cell lung cancer (NSCLC; stage IV) from the 'Theageneio' Cancer Hospital (Thessaloniki, Greece). Several parameters were assessed, such as body mass index (BMI), lean mass, PhA, Mediterranean diet score (MedDietScore), dietary patterns, smoking, resting metabolic rate, resting oxygen consumption (VO₂), ventilation rate, and physical activity. Results: According to our results, a dietary pattern rich in potatoes and animal proteins (meat and poultry) was a significant determinant of PhA (B ± SE, p: 0.165 ± 0.08, p = 0.05) in multiple linear regression models after adjusting for age, smoking, lean tissue, and MedDietScore. Conclusion: In conclusion, dietary patterns may affect PhA, suggesting the crucial role of protein in cancer management and the prevention of sarcopenia.

Factors of Muscle Quality and Determinants of Muscle Strength: A Systematic Literature Review

Muscle quality defined as the ratio of muscle strength to muscle mass disregards underlying factors which influence muscle strength. The aim of this review was to investigate the relationship of phase angle (PhA), echo intensity (EI), muscular adipose tissue (MAT), muscle fiber type, fascicle pennation angle (θf), fascicle length (lf), muscle oxidative capacity, insulin sensitivity (IS), neuromuscular activation, and motor unit to muscle strength. PubMed search was performed in 2021. The inclusion criteria were: (i) original research, (ii) human participants, (iii) adults (≥18 years). Exclusion criteria were: (i) no full-text, (ii) non-English or -German language, (iii) pathologies. Forty-one studies were identified. Nine studies found a weak−moderate negative (range r: [−0.26]−[−0.656], p < 0.05) correlation between muscle strength and EI. Four studies found a weak−moderate positive correlation (range r: 0.177−0.696, p < 0.05) between muscle strength and PhA. Two studies found a moderate-strong negative correlation (range r: [−0.446]−[−0.87], p < 0.05) between muscle strength and MAT. Two studies found a weak-strong positive correlation (range r: 0.28−0.907, p < 0.05) between θf and muscle strength. Muscle oxidative capacity was found to be a predictor of muscle strength. This review highlights that the current definition of muscle quality should be expanded upon as to encompass all possible factors of muscle quality.

Association between Phase Angle from Bioelectric Impedance and Muscular Strength and Power in Physically Active Adults

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 2nd 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.

Age-, sex-, and maturity-associated variation in the phase angle after adjusting for size in adolescents

Background

Applied research using the phase angle (PhA) in children and adolescents has increased notably. Using multilevel modeling in a fully Bayesian framework, we examined the relationships between PhA, age, sex, biological maturity status, and body size in 10–16-year-old adolescents.

Methods

The sample comprised 519 adolescents (women, n = 241; men, n = 278) from Campinas, São Paulo, Brazil. Biological maturity status was assessed with self-examination of pubertal development for sexual maturity and maturity offset protocol to estimate age at peak height velocity (PHV) for somatic maturity status. Stature and body mass were measured by anthropometry. Phase angle was calculated based on raw resistance and reactance values (50 kHz frequency) obtained by bioelectrical impedance with the foot-to-hand technology.

Results

The multilevel regression analysis revealed that boys had significantly higher values of phase angle than girls, adjusting for age group and sexual maturity status. Overall, older and more mature adolescents had higher values of phase angle. When considering aligning variation in the phase angle by distance to estimated PHV (maturity offset), there was a higher association between the phase angle and time before and after predicted age at PHV for boys (r = 0.31, 90% CI: 0.23 to 0.39) than girls (r = 0.2, 90% CI: 0.11 to 0.28). When including body mass in the multilevel models, corresponding changes in the overall body mass mediate most of the influence of the maturity status and age group on the phase angle.

Conclusion

The present study demonstrated that the variability in phase angle is related to inter-individual variation in sex, age, and maturity status, as well as differences in body size. Research with adolescents considering phase angle should use multilevel modeling with standardized parameters as default to adjust for the concurrent influence of sex, age, maturity status, and body size.

Bioelectrical Impedance Analysis (BIA)- Derived Phase Angle in Children and Adolescents: A Systematic Review

Phase angle (PhA), a directly-measured bioelectrical impedance analysis variable, is suggested to be a proxy of body cell mass as well as extracellular/intracellular water ratio, and is related to cellular integrity and functions. The aim of this systematic review was to evaluate PhA in healthy youths in relation to sex, age, weight status, physical fitness, and sports activities. A systematic literature search (preferred reporting items for systematic reviews and meta-analyses criteria) until January 2022 was performed using PubMed, Embase, Scopus, and Web of Science regarding studies on PhA in healthy children and adolescents 4-18 years of age. Quality was assessed according to the National Institute of Health. After removing duplicates and studies not fulfilling the inclusion criteria, 22 cross-sectional and 1 longitudinal were considered appropriate. As for quality, 14 articles were rated fair and 9 good. Ten studies found that PhA increases with age: the increase was more marked after puberty, whereas changes in younger subjects are by far less defined. A clear sex difference was found in adolescents, likely due to pubertal development. Limited evidence suggests that PhA increases in participants with very high BMI. Limited data were reported on physically active youths without convincing findings. Positive associations of PhA with physical fitness and fat-free mass were found in few studies. In conclusion, partial and limited evidence suggests that changes in PhA over the first 2 decades of life reflect modification in body composition and fat-free mass composition. Further studies are needed for confirming PhA as a relevant marker of nutritional status in youths.

Effects of an individualized and progressive multicomponent exercise program on blood pressure, cardiorespiratory fitness, and body composition in long-term care residents: Randomized controlled trial

This study analyzed the effects of an individualized and progressive multicomponent exercise program on blood pressure, cardiorespiratory fitness, and body composition in long-term care residents. This was a single-blind, multicenter, randomized controlled trial performed in 10 long-term care settings and involved 112 participants. Participants were randomly assigned to a control group or an intervention group. The control group participated in routine activities; the intervention group participated in a six-month individualized and progressive multicomponent exercise program focused on strength, balance, and walking recommendations. The intervention group maintained peak VO₂, oxygen saturation, and resting heart rate, while the control group showed a significant decrease in peak VO₂ and oxygen saturation and an increase in resting heart rate throughout the six-month period. Individualized and progressive multicomponent exercise programs comprising strength, balance, and walking recommendations appear to be effective in preventing cardiorespiratory fitness decline in older adults living in long-term care settings.

Evaluating Sarcopenia by Using the Bioelectrical Impedance Analysis in Patients with Acute Myeloid Leukemia After Chemotherapy

Background

We aimed to explore the potential association of body composition parameters measured by bioelectrical impedance analysis (BIA) with the incidence of sarcopenia in patients with acute myeloid leukemia (AML) (non-M3) after chemotherapy.

Patients and Methods

This was a single-center observational study. Sixty-nine patients with newly diagnosed AML underwent BIA at the time of initial diagnosis and after completion of three chemotherapy sessions. Pre- and post-chemotherapy BIA parameters were compared. Sarcopenia was defined as low skeletal muscle mass plus low muscle strength according to the Asian Working Group for Sarcopenia (AWGS). Association of sarcopenia with mid-arm muscle circumference (MAMC) and intracellular water (ICW) was assessed by multivariate logistic regression.

Results

There was a significant increase in the prevalence of sarcopenia after chemotherapy (39.1% vs 14.5%, P<0.001). Skeletal muscle mass (SMM), fat-free mass (FFM), and soft lean mass (SLM) showed a significant decrease after chemotherapy (P<0.05). MAMC, ICW, and total body water (TBW) significantly decreased after chemotherapy (P<0.05). BIA indices including appendicular skeletal muscle mass (ASM) (r=0.889, P<0.001), ICW (r=0.869, P<0.001), MAMC (r=0.849, P<0.001) showed a positive correlation with SMI. Moreover, ASM (r=−0.453 P=0.001), ICW (r=−0.322, P<0.05), and MAMC (r=−0.352, P<0.05) showed a negative correlation with sarcopenia. On multivariate logistic regression analysis, increased ICW was associated with decreased risk of sarcopenia [odds ratio (OR): 0.50; 95% confidence interval (CI) 0.30–0.82]. Each additional unit of MAMC after chemotherapy was associated with 71% lower risk of sarcopenia (OR: 0.29; 95% CI 0.13–0.66).

Conclusion

The incidence of sarcopenia was associated with chemotherapy of patients with AML (non-M3) as reflected by body composition changes.

Relationships between Body Composition Parameters and Phase Angle as Related to Lifestyle among Young People

The aim of the study was to indicate which body composition parameters and which lifestyle components affect the phase angle (PA) value in young adults. Two-hundred-and-eighty-one students at Wroclaw Medical University participated in the study. A survey on respondent lifestyles was followed by anthropometric measurements, body composition analysis, and basal metabolic rate (BMR) calculation. The differences in the body composition of men and women corresponded to their sexual anatomy and physiology. Sex-dependent differences in lifestyle were also reported. The study revealed a relationship between PA and height, weight, BMR, BMI (body mass index), FFM (fat-free body mass), bone mass, water mass, muscle mass (r~0.4–0.7), ECW/ICW (extracellular water/intracellular water) and fat mass (r~−(0.4–0.6)) for the entire studied group. The relationship between PA values and lifestyle components concerned consumption of energy drinks, cola, alcohol, water, vegetables and fruits, meat, and also intervals between meals, time for physical exercises, and screen time (r~±0.2). The research shows that the PA value increases with an increase in positive body composition parameters. Following the principles of proper nutrition and physical activity increases PA values in most cases.

Skeletal muscle quality in 6- and 7-y-old children assessed using bioelectrical impedance analysis

OBJECTIVES

The condition of skeletal muscles is a key marker of the nutritional status and function of an organism. It is necessary to monitor muscle quality in basic pediatric preventive health care, especially due to the increase in negative health behaviors during a pandemic. The aims of this study were to assess body composition and muscle strength as well as to analyze the relationship between muscle functional quality and impedance parameters in 6- and 7-y-old children.

METHODS

The study involved 292 healthy 6- and 7-y-old children. Handgrip strength and bioimpedance parameters were measured. Body composition components, including appendicular skeletal muscle mass, were estimated. Handgrip strength in relation to the appendicular skeletal muscles mass was adopted as an indicator of the muscle functional quality. The relationship between the muscle quality index and impedance parameters was assessed by multiple regression.

RESULTS

A 1-y age difference between the children differentiated not only basic somatic parameters, body composition, and handgrip strength, but also the electrical properties of the tissues. The relative difference in muscle mass between younger and older children was twice that of the muscle strength. A significant regression model of the muscle quality index was obtained, in which reactance and impedance phase angle were strong positive predictors. Adjusted fat mass negatively correlated with the muscle quality.

CONCLUSIONS

Reactance and phase angle are good indicators of the quality of appendicular skeletal muscle in healthy children and can be potentially used in pediatric preventive health care and screening.

Body Composition and Bioelectrical-Impedance-Analysis-Derived Raw Variables in Pole Dancers

Few data are available on the body composition of pole dancers. Bioelectrical impedance analysis (BIA) is a method that is used to estimate fat-free mass (FFM) and fat mass (FM), while raw BIA variables, such as the impedance ratio (IR) and phase angle (PhA), are markers of body cell mass and the ratio between extracellular and total body water. The aim of this study was to evaluate the body composition of pole dancers compared to controls, in particular, those raw BIA variables that are considered as markers of muscle composition. Forty female pole dancers and 59 controls participated in the study. BIA was performed on the whole body and upper and lower limbs, separately, at 5, 50, 100 and 250 kHz. The FFM, FFM index, FM and body fat percentage (BF%) were predicted. The bioelectrical impedance indexes IR and PhA were also considered. Pole dancers exhibited higher FFMI and BI indexes and lower BF%. PhA was greater and IRs were smaller in pole dancers than in controls for the whole body and upper limbs. Considering the training level, FFM, whole-body IR and PhA were higher in the professionals than non-professionals. Raw BIA variables significantly differed between the pole dancers and controls, suggesting a higher BCM; furthermore, practicing pole dancing was associated with a greater FFM and lower FM.

Raw bioelectrical impedance analysis variables (phase angle and impedance ratio) are significant predictors of hand grip strength in adolescents and young adults

OBJECTIVES

Musculoskeletal fitness and body composition are major components of health-related physical fitness that are expected to be linked to each other. The aim of this study was to explore the association of musculoskeletal fitness (expressed as hand grip strength [HGS]) and raw bioelectrical impedance analysis (BIA) variables and other predictors in the second and third decades of life.

METHODS

Four groups of healthy normal-weight and overweight participants were studied: 130 male adolescents (age 16.0 ± 1.1 y), 143 female adolescents (16.0 ± 0.9 y), 141 young men (25.5 ± 2.0 y), and 141 young women (25.2 ± 1.9 y). Raw BIA variables (impedance [Z] and phase angle [PhA]) for the whole body were measured at four frequencies (5, 50, 100, and 250 kHz), and HGS was measured in both upper limbs.

RESULTS

HGS was higher in males than females and higher in young men than male adolescents. A fairly strong correlation emerged in both genders between HGS and raw BIA variables-that is, bioimpedance index (height²/Z), PhA, and impedance ratios (Z at high frequency/Z at low frequency). In multiple regression analysis, bioimpedance index, PhA, and impedance ratio were more effective predictors of HGS than BIA-derived estimates of body composition or anthropometric variables such as height, weight, and body mass index. In both genders, HGS was significantly higher in young adults than in adolescents for the same PhA or impedance ratio.

CONCLUSIONS

This study provides some insight into the use of raw BIA variables and HGS in the first decades of life, suggesting a new approach for a reliable assessment of muscle quality in terms of both muscle structure and strength.

Association of phase angle and appendicular upper and lower body lean soft tissue with physical performance in young elite soccer players: a pilot study

BACKGROUND

In soccer, a better understanding of the bioimpedance parameters with physical performance may be useful to efficiently monitor and interpret players' performance variation throughout a certain period of the season. Therefore, this study aimed to examine the association between phase angle (PhA) and arms and legs lean soft tissue (ALST and LLST) with physical performance in young elite soccer players.

METHODS

Fifteen young male elite soccer players (age = 14.2±1.2 years, BMI = 20.51±1.38 kg/m2) participated in this investigation. Raw bioimpedance parameters (reactance, resistance, and phase angle) were obtained by a bioelectrical impedance analysis (BIA) device. Then, ALST and LLST were estimated. All players underwent a physical testing battery including countermovement jump (CMJ), 10-m and 20-m sprint, and Yo-Yo Intermittent Recovery Test level 1 (YoYo IRTL1) in the domains of anaerobic and aerobic performance, respectively.

RESULTS

The results showed that LST (total, arms and legs) positively correlated with CMJ (0.64 < r < 0.69; p < 0.001) and negatively correlated with 10-m (-0.59 < r < -0.63; p < 0.05) and 20-m sprint (-0.67 < r < -0.73; p < 0.001), while PhA positively correlated with CMJ (r = 0.57; p < 0.05) and negatively correlated (r = -0.54; p < 0.05) only with 20-m sprint. No significant association was found between the BIA-related parameters (PhA and LST) and Yo- Yo IRT level 1.

CONCLUSIONS

The present findings highlight the existing association of PhA and LST with jumping and sprinting performance in young elite soccer players. This result supports the use of BIA-related measures as a simple and practical approach to monitoring anaerobic performance changes, rather than aerobic, over time throughout the season.

Association of phase angle with muscle strength and aerobic fitness in different populations: A systematic review

OBJECTIVES

The aim of this study was to summarize the evidence on the association of phase angle (PhA) with muscle strength and aerobic fitness in different populations.

METHODS

A systematic search on this topic was performed in nine electronic databases (CINAHL, LILACS, PubMed, SciELO, Scopus, SPORTDiscus, ScienceDirect, MEDLINE, and Web of Science) in January 2021. Studies with different designs that permitted extraction of information about the relationships between PhA and muscle strength and between PhA and aerobic fitness were included. A total of 4446 studies were initially identified; 34 were included after reading of the title, abstract, full text, and references. Four of the studies included had a longitudinal design, with samples consisting of participants ages 6 to 92 years. Thirty-two of the 34 studies evaluated the relationship between PhA and muscle strength, two cross-sectional studies investigated only PhA and aerobic fitness, and three cross-sectional studies evaluated both components (muscle strength and aerobic fitness).

RESULTS

PhA was directly associated with muscle strength in 30 cross-sectional studies and two longitudinal studies; the two studies that did not find a direct relationship had a cross-sectional design. For aerobic fitness, the five studies identified reported a direct relationship with PhA.

CONCLUSIONS

PhA is directly associated with muscle strength and aerobic fitness in different age groups (children, adolescents, adults, and older adults) and in people with different health conditions (human immunodeficiency virus, Crohn's disease, chronic obstructive pulmonary disease, bariatric surgery, kidney transplant, cancer, hemodialysis, and sarcopenia).

New Frontiers of Body Composition in Sport

The body composition phenotype of an athlete displays the complex interaction among genotype, physiological and metabolic demands of a sport, diet, and physical training. Observational studies dominate the literature and describe the sport-specific physique characteristics (size, shape, and composition) of adult athletes by gender and levels of competition. Limited data reveal how body composition measurements can benefit an athlete. Thus, the objective is to identify purposeful measurements of body composition, notably fat and lean muscle masses, and determine their impact on the health and performance of athletes. Areas of interest include relationships among total and regional body composition measurements, muscle function, sport-specific performance, risk of injury, return to sport after injury, and identification of activity-induced fluid shifts. Discussion includes the application of specific uses of dual X-ray absorptiometry and bioelectrical impedance including an emphasis on the need to minimize measurement errors and standardize protocols, and highlights opportunities for future research. This focus on functional body composition can benefit the health and optimize the performance of an athlete.

Whole body and regional phase angle as indicators of muscular performance in athletes

Bioelectrical impedance analysis (BIA)-derived phase angle (PhA) has been used to assess cellular health in various populations, but its usefulness as a tool for measuring muscular performance in adult athletes has not been extensively investigated. Our investigation examined the association of whole-body (WB) PhA with muscular performance in 117 adult athletes from different sports and additionally assessed whether regional PhA was a better indicator of muscular performance compared to WB, while accounting for lean soft tissue (LST). Muscular performance was assessed with handgrip strength and countermovement jump power. WB and regional PhA and LST were obtained by BIA and dual-energy x-ray absorptiometry, respectively. Multiple linear regression was used to model outcomes, while adjusting for LST. WB PhA was positively associated with relative power and relative and absolute strength (p < 0.05), irrespective of LST. Regional PhA measures explained similar amounts of variance in absolute and relative power and strength as that of WB PhA after accounting for age, sex, height, and sport type (lower limb adj R² = 0.42, 0.60 for power; upper limb adj R² = 0.38, 0.74 for strength; WB adj R² = 0.44, 0.63 and 0.38, 0.75 for power and strength, respectively). Only upper limb PhA was related with strength (p < 0.05) after accounting for upper limb LST. PhA may have the potential to be used as a marker of functional muscle mass, which is important when it comes to assessing muscular performance of athletes. Regional measures of PhA do not provide a better indicator of regional strength or power when compared to WB PhA.

Correlation between the SARC-F Score and Hydration Status in Older Gastrointestinal Cancer Outpatients

OBJECTIVES

The aim of this study was to assess the association between the extracellular water/total body weight ratio (ECW/TBW) and SARC-F scores among elderly gastrointestinal cancer patients.

MEASUREMENTS

A cross-sectional study was performed with 57 older male patients with gastrointestinal cancer. Muscle function was assessed using the SARC-F questionnaire. Total body water (TBW) and extracellular water (ECW) were determined using bioelectrical impedance analysis, and fluid retention was assessed as the ratio of ECW to TBW (ECW/TBW). Pearson´s correlation analysis was used to assess the relationship between the SARC-F score and ECW/TBW, TBW and water intake. Results were considered significant at p < 0.05.

RESULTS

Of the 57 older patients evaluated (65 ± 7 y), 13 ± 8% presented severe weight loss in the last 6 months. The median SARC-F score was 1.0 (0-10), and only four patients had SARC-F ≥4, which indicates the risk of sarcopenia. There was a positive correlation between the SARC-F score and ECW/TBW (r = 0.26, p = 0.02). However, no correlation was found between daily water intake or TBW and the SARC-F score.

CONCLUSION

In older gastrointestinal cancer outpatients, we found a positive, albeit low, correlation between the SARC-F score and the ECW/TBW ratio. This outcome indicates the likelihood of muscle function loss due to accumulation of extracellular fluid.

Effectiveness of impedance parameters for muscle quality evaluation in healthy men

We investigated the relationship between impedance parameters and skeletal muscle function in the lower extremities, as well as the effectiveness of impedance parameters in evaluating muscle quality. Lower extremity impedance of 19 healthy men (aged 23-31 years) measured using the direct segmental multi-frequency bioelectrical impedance analysis were arc-optimized using the Cole-Cole model, following which phase angle (PA), [Formula: see text], and β were estimated. Skeletal muscle function was assessed by muscle thickness, muscle intensity, and isometric knee extension force (IKEF). IKEF was positively correlated with PA (r = 0.58, p < 0.01) and β (r = 0.34, p < 0.05) was negatively correlated with [Formula: see text] (r = - 0.43, p < 0.01). Stepwise multiple regression analysis results revealed that PA, β, and [Formula: see text] were correlated with IKEF independently of muscle thickness. This study suggests that arc-optimized impedance parameters are effective for evaluating muscle quality and prediction of muscle strength.

Phase Angle from Bioelectric Impedance and Maturity-Related Factors in Adolescent Athletes: A Systematic Review

Phase angle (PhA) is a body composition (BC) parameter from bioelectrical impedance analysis that is suggested as a marker of cell integrity and general health. In adolescent athletes, PhA values are used to monitor the effects of training and competitions and seem to vary according to age, having an upward trajectory during puberty. Since adolescence is a period composed of maturation stages, the aim of this systematic review was to investigate the relationship between PhA and maturation stage in adolescent athletes. A search was conducted in PubMed/MEDLINE, BVS, Web of Science (WOS), Scopus, Science Direct, and Academic Search Complete (EBSCO) databases up to May 2020. Eligibility criteria followed the PICOS strategy and studies with healthy athletes aged 10–19 years of any level of competition were included. Six cross-sectional studies and two longitudinal studies met the inclusion criteria. Results showed that early and mature athletes have higher PhA than those who are non-matured or maturated late. Thus, PhA is influenced by the pubertal status. Considering BC is one of the factors influencing sports performance together with its growth-related changes, practitioners may use PhA values in BC analysis of adolescent athletes.