•Phase angle was directly associated with isolated and grouped physical fitness indicators in adolescents.•The phase angle values can vary according to physical fitness, which indicates the use of ...phase angle as a marker that presents variability depending on the level of physical fitness of adolescents.•The phase angle is as a useful tool to be used in physical assessments and screening of recommendations for physical activity, physical exercise, and health-related physical fitness.
Objective: Examine association between phase angle and isolated and grouped physical fitness indicators in adolescents. Methods: The sample consisted of 353 adolescents, aged 10–16 years. Phase angle was calculated based on crude resistance and reactance values (50 kHz frequency) obtained by tetrapole electrical bioimpedance (BIA). Fat mass and lean mass were estimated by means of anthropometric equations. Hydraulic dynamometer was used to measure handgrip strength and aerobic fitness was obtained by means of the 20-m back-and-forth test. The z-score for isolated and grouped physical fitness indicators was calculated. Covariates were age, habitual physical activity and screen time (obtained by questionnaire), and sexual maturation (self-reported). Results: For males, phase angle was directly associated with lean mass (β = 0.02, p < 0.01), handgrip strength (β = 0.03, p < 0.01), and aerobic fitness (β = 0.01, p = 0.05), even adjusting for covariates. For females, phase angle was directly associated with lean mass (β = 0.02; p = 0.04) after adjusting for covariates. Phase angle was directly associated with composite physical fitness z-score in both sexes (male, β = 0.09, p < 0.01, female, β = 0.03, p = 0.05), even adjusting for covariates. Conclusions: Phase angle was directly associated with isolated and grouped physical fitness indicators in adolescents. In this way, the phase angle can be used to monitor the health of adolescents.
Rodrigues de Lima, T, Custódio Martins, P, Henrique Guerra, P, and Augusto Santos Silva, D. Muscular fitness and cardiovascular risk factors in children and adolescentsA systematic review. J Strength ...Cond Res 34(8)2394–2406, 2020—The purpose of this study was to identify and summarize the relationships between muscular fitness (MF) and individual components of metabolic syndrome (high waist circumference WC, high blood pressure BP, high systolic BP SBP, high diastolic BP DBP, high triglycerides TG, fasting blood glucose FG, and low HDL cholesterol levels HDL-C) in children and adolescents. A systematic review was conducted in 5 electronic databases, with complementary searches in reference lists, and the inclusion criteria were children and adolescents (age group up to 19 years of age) with no special clinical conditions. In all articles, risk of bias was analyzed by a standardized instrument. Of the 5,973 articles initially identified, 21 were included, with data on 22,261 children and adolescents. Higher MF values were associated with lower TG (n = 07) and WC values (n = 15). Different results in relation to the relationship between MF and SBP (n = 10) and MF and DBP (n = 07) were verified. In addition, there was no relationship between MF and FG (n = 06). In addition, inconclusive results were verified in the relationship between MF and HDL-C (n = 07). Concluded higher MF values were related to lower WC values and lower TG concentrations.
Bioelectrical impedance vector analysis (BIVA) is able to identify differences in hydration status and body composition components, such as body cell mass (BCM) by means of plotting individuals in ...ellipses, when comparing groups with different characteristics.
Compare the confidence and tolerance ellipses of BIVA in individual and team sports athletes with a non-athlete reference population.
One hundred sixty-seven college athletes (team sports: 117 athletes, individual sports: 50 athletes) aged between 18 and 35 years. Bioelectrical impedance was used to measure resistance (R) and reactance (Xc) values that were used in the BIVA analysis to identify hydration status and BCM, respectively. Hotelling's t-test was used to identify differences between groups in the confidence ellipses and the comparison was made with a non-athlete Italian reference population.
There were no differences between male team sports and individual athletes (p = 0.151) and for female athletes (p = 0.624). Most athletes were located in the 50% tolerance ellipses, indicating adequate hydration. Compared to the Italian a non-athlete population, athletes of both sexes presented left impedance vector deviation in the minor axis (Xc) of the tolerance ellipses, indicating higher BCM.
There were no differences in BIVA between team and individual sports athletes, but most athletes presented an adequate hydration state and, compared to a non-athlete population, the athletes of the present study presented higher BCM.
To examine the association between phase angle (PhA) and bioelectrical impedance vector analysis (BIVA) and components of physical performance in male youth soccer players.
Cross-sectional.
Sixty-two ...players from two professional soccer academies were recruited. Electrical bioimpedance was used to obtain the PhA and BIVA. Body fat (BF) and lean soft tissue mass (LSTM) were measured by dual-energy X-ray absorptiometry. All players completed physical tests including the standing long jump (SLJ), Carminatti's test (peak speed at the end of the test, PS
), 10 m and 30 m straight-line sprints, and repeated-sprint ability (RSA) test (RSAbest and RSAmean times).
Adjusting for chronological age, BF, and LSTM, multiple regression analysis outputs showed that PhA remained inversely related to RSAmean (β = -0.362;
< 0.001), RSAbest (β = -0.239;
= 0.020), 10 m (β = -0.379;
= 0.012), and 30 m (β = -0.438;
< 0.001) sprint times, while the association with PS
and SLJ performance were statistically non-significant. In addition, BIVA showed that differences in confidence ellipses were found between athletes in the reference population and the study sample (
< 0.05). The tolerance ellipses indicated that the athletes in the present study had more total body water (TCW) and lower proportions of intracellular water (ICW) to extracellular water (ECW). The reference population had more TCW and ICW/ECW.
Our results suggest that young soccer players with higher PhA values, indicating better cell integrity and functionality, have better performance in typical anaerobic running activities, such as sprinting speed and RSA performance, adjusted to age and body composition characteristics.
BACKGROUNDDuring childhood and adolescence, there are significant increases in bone mineral content (BMC) and bone mineral density (BMD). OBJECTIVETo investigate physical growth parameters associated ...with BMD and BMC among children and adolescents diagnosed with human immunodeficiency virus (HIV). DESIGN AND SETTINGCross-sectional study conducted in Florianópolis, Brazil, among 63 children and adolescents (aged 8-15 years) diagnosed with HIV. METHODBMD, BMC and fat percentage z score were evaluated using dual X-ray absorptiometry. Age/height z score and body mass index (BMI)/age z score were obtained in accordance with international recommendations, and bone age was obtained through hand-wrist radiography. Sex, family income, information on HIV infection (T CD4+ lymphocyte count, viral load and type of antiretroviral therapy, moderate-vigorous physical activity and sedentary behavior) were used as adjustment variables in the analyses. Simple and multiple linear regression analyses were performed, with a significance level of P ≤ 0.05. RESULTSSubtotal BMD (without the head region) was directly associated with bone age, BMI/age z score and fat percentage z score, even after adjusting for covariates. Subtotal BMC/height was directly associated with bone age, height/age z score, BMI/age z score and fat percentage z score, even after adjusting for covariates. CONCLUSIONSubtotal BMD and subtotal BMC/height were directly associated with physical growth indicators among children and adolescents diagnosed with HIV.
Studies that test associations between anthropometric indicators and insulin resistance (IR) need to provide better evidence in the context of the pediatric population (children and adolescents) with ...human immunodeficiency virus (HIV), as anthropometric indicators present a better explanation of the distribution of body fat.
To test the associations between anthropometric indicators and insulin resistance (IR) among children and adolescents diagnosed with HIV.
Cross-sectional study on 65 children and adolescents (8-15 years) infected with HIV through vertical transmission conducted at the Joana de Gusmão Children's Hospital, Florianópolis, Brazil.
The anthropometric indicators measured were the abdominal (ASF), triceps (TSF), subscapular (SSF) and calf (CSF) skinfolds. The relaxed arm (RAC), waist (WC) and neck (NC) circumferences were also measured. Body mass index (BMI) was calculated from the relationship between body mass and height. IR was calculated through the Homeostasis Model Assessment for Insulin Resistance (HOMA-IR). Simple and multiple linear regression analyses were used.
After adjustment for covariates (sex, bone age, CD4+ T lymphocytes, CD8+ T lymphocytes, viral load, and physical activity), associations between IR and models with SSF and CSF remained. Each of these explained 20% of IR variability. For females, in the adjusted analyses, direct associations between IR and models with ASF (R² = 0.26) and TSF (R² = 0.31) were observed.
SSF and CSF in males and ASF and TSF in females were associated with IR in HIV-infected children and adolescents.
The aim of the study was to investigate how phase angle (PhA) is associated with subtotal and lumbar spine bone mineral density BMD, lean soft tissue mass LSTM, total body fat mass, android and ...gynoid in children and adolescents with HIV according to sex. A cross-sectional study was conducted in Florianópolis, Brazil, involving 64 children and adolescents vertically transmitted with HIV. Resistance and reactance values were obtained using bioelectrical impedance analysis, and PhA was subsequently calculated. Dual emission X-ray absorptiometry was used to assess body composition. Antiretroviral medication, physical activity (accelerometers) and skeletal maturation (wrist-carpal radiography) were used in the adjusted model. In males, PhA was directly associated with subtotal BMD (βadj: 0.65; R²: 0.38, p < 0.01) and lumbar spine BMD (βadj: 0.53; R²: 0.22, p = 0.01), directly associated with LSTM (βadj: 0.76; R²: 0.46, p < 0.01), and inversely associated with gynoid fat (βadj: −0.47; R²: 0.2, p = 0.01), in adjusted models. In females, PhA was directly associated with subtotal BMD (βadj: 0.46; R²: 0.17, p < 0.01) and lumbar spine BMD (βadj: 0.48; R²: 0.19, p < 0.01). It is concluded that PhA was directly associated with subtotal and regional BMD, LSTM, and inversely with gynoid fat in boys with HIV. In girls, PA was directly associated only with subtotal and regional BMD.
BACKGROUNDLow bone mineral content (BMC) and bone mineral density (BMD) have been identified in human immunodeficiency virus (HIV)-infected children and adolescents. The direct adverse effects of HIV ...infection and combined antiretroviral therapy (ART) negatively contribute to bone metabolism. A direct relationship between muscle strength levels and BMD in HIV-infected adults and older adults has been described. However, it is unknown whether handgrip strength (HGS) is associated with bone mass in pediatric populations diagnosed with HIV. OBJECTIVETo ascertain whether HGS levels are associated with BMC and BMD in HIV-infected children and adolescents. DESIGN AND SETTINGCross-sectional study conducted in Florianãpolis, Brazil, in 2016. METHODSThe subjects were 65 children and adolescents (8-15 years) diagnosed with vertically-transmitted HIV. Subtotal and lumbar-spine BMC and BMD were obtained via dual-emission X-ray absorptiometry (DXA). HGS was measured using manual dynamometers. The covariates of sex, ART, CD4+ T lymphocytes and viral load were obtained through questionnaires and medical records. Sexual maturation was self-reported and physical activity was measured using accelerometers. Simple and multiple linear regression were used, with P < 0.05. RESULTSHGS was directly associated with subtotal BMD (β = 0.002; R² = 0.670; P < 0.001), subtotal BMC (β = 0.090; R² = 0.734; P = 0.005) and lumbar-spine BMC (β = 1.004; R² = 0.656; P = 0.010) in the adjusted analyses. However, no significant association was found between HGS and lumbar-spine BMD (β = 0.001; R² = 0.464; P = 0.299). CONCLUSIONHGS was directly associated with BMD and BMC in HIV-infected children and adolescents.
To identify sociodemographic, physical activity, and physical fitness factors associated with flexibility.
Cross-sectional study with 909 adolescents (486 girls) aged 14 to 19 years from the city of ...São José, Santa Catarina, Brazil. To evaluate flexibility, we used the sit and reach test. Sociodemographic and physical activity data were collected by a self-administered questionnaire. We analyzed muscle strength with manual dynamometry. Aerobic fitness was assessed with the modified Canadian aerobic fitness test, and physical activity with a questionnaire. We used multiple linear regression to identify the variables associated with flexibility, with a significance level of 5%.
For each additional centimeter in the girls' levels of flexibility, the boys were 2.94 cm less flexible. In addition, the increment of 0.12 kg/force in muscle strength levels increased the levels of flexibility in 1 cm.
Lower levels of flexibility were associated with male adolescents and with reduced strength levels.
Background: HIV infection and prolonged use of antiretroviral therapy (ART) can impact the body composition and muscle strength of HIV-infected children and adolescents. Therefore, the aim was to ...verify the association between lean soft tissue mass (LSTM) and handgrip strength (HGS) in children and adolescents diagnosed with HIV using or not using ART (with or without protease inhibitors PI).
Method: Cross-sectional study with 65 children and adolescents diagnosed with HIV aged 8-15 years of both sexes. LSTM was obtained through dual X-ray absorptiometry (DXA) and HGS using hydraulic dynamometer. Information on viral load, CD4+ T lymphocytes and type of ART (with or without PI) were obtained from medical records. Simple and multiple linear regression (adjusted for viral load and CD4+ T lymphocytes) was used, with p < 0.05.
Results: For children and adolescents diagnosed with HIV using ART without PI, the model (LSTM, viral load and CD4+ T lymphocytes) explained 68% of HGS variability. For group with ART and PI, the model explained 73%. For group that did not use ART, the model was not associated with HGS.
Conclusion: The magnitude of the association between LSTM and HGS was greater than in children and adolescents using ART with PI.
Impact
It is recognized that in the long-term antiretroviral drugs can negatively impact the body composition of children and adolescents diagnosed with HIV. However, few studies have investigated the short-term impact of drug use.
The use of antiretroviral therapy (ART) with protease inhibitor (PI) increased the explanatory power of lean soft tissue mass with muscle strength in children and adolescents diagnosed with HIV.
These results demonstrate the importance of antiretroviral drugs in the short term. Further studies are needed to identify how and when interventions are needed to reduce the negative effects of drugs in the long term.
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