Abnormal exercise adaptation after varying severities of COVID-19: A controlled cross-sectional analysis of 392 survivors.

The multisystem impairment promoted by COVID-19 may be associated with a reduction in exercise capacity. Cardiopulmonary abnormalities can change across the acute disease severity spectrum. We aimed to verify exercise physiology differences between COVID-19 survivors and SARS-CoV-2-naïve controls and how illness severity influences exercise limitation. A single-centre cross-sectional analysis of prospectively collected data from COVID-19 survivors who underwent cardiopulmonary exercise testing (CPET) in their recovery phase (x = 50[36;72] days). Patients with COVID-19 were stratified according to severity as mild [M-Cov (outpatient)] vs severe/critical [SC-Cov(inpatients)] and were compared with SARS-CoV-2-naïve controls (N-Cov). Collected information included demographics, anthropometrics, previous physical exercise, comorbidities, lung function test and CPET parameters. A multivariate logistic regression analysis was performed to identify low aerobic capacity (LAC) predictors post COVID-19. Of the 702 included patients, 310 (44.2%), 305 (43.4%) and 87 (12.4%) were N-Cov, M-Cov and SC-Cov, respectively. LAC was identified in 115 (37.1%), 102 (33.4%), and 66 (75.9%) of N-CoV, M-CoV and SC-CoV, respectively (p < 0.001). SC-Cov were older, heavier with higher body fat, more sedentary lifestyle, more hypertension and diabetes, lower forced vital capacity, higher prevalence of early anaerobiosis, ventilatory inefficiency and exercise-induced hypoxia than N-Cov. M-Cov had lower weight, fat mass, and coronary disease prevalence and did not demonstrate more CEPT abnormalities than N-Cov. After adjustment for covariates, SC-Cov was an independent predictor of LAC (OR = 2.7; 95% CI, 1.3-5.6). Almost two months after disease onset, SC-CoV presented several exercise abnormalities of oxygen uptake, ventilatory adaptation and gas exchange, including a high prevalence of LAC.Highlights Weeks after the acute disease phase, one-third of mild and three-quarters of severe and critical patients with COVID-19 presented a reduced aerobic capacity. Previous studies including SARS-CoV-1 survivors observed much lower values.A severe or critical COVID-19 case was an independent predictor for low aerobic capacity.In our sample, pre-COVID-19 exercise significantly reduced the odds of post-COVID-19 low aerobic capacity. Even severe or critical patients who exercised regularly had a prevalence of low aerobic capacity 2.5 times lower than those who did not have this routine before sickening.

Oxygen uptake kinetics and chronotropic responses to exercise are impaired in survivors of severe COVID-19.

The post-acute phase of coronavirus disease 2019 (COVID-19) is often marked by several persistent symptoms and exertional intolerance, which compromise survivors' exercise capacity. This was a cross-sectional study aiming to investigate the impact of COVID-19 on oxygen uptake (V̇o2) kinetics and cardiopulmonary function in survivors of severe COVID-19 about 3-6 mo after intensive care unit (ICU) hospitalization. Thirty-five COVID-19 survivors previously admitted to ICU (5 ± 1 mo after hospital discharge) and 18 controls matched for sex, age, comorbidities, and physical activity level with no prior history of SARS-CoV-2 infection were recruited. Subjects were submitted to a maximum-graded cardiopulmonary exercise test (CPX) with an initial 3-min period of a constant, moderate-intensity walk (i.e., below ventilatory threshold, VT). V̇o2 kinetics was remarkably impaired in COVID-19 survivors as evidenced at the on-transient by an 85% (P = 0.008) and 28% (P = 0.001) greater oxygen deficit and mean response time (MRT), respectively. Furthermore, COVID-19 survivors showed an 11% longer (P = 0.046) half-time of recovery of V̇o2 (T1/2V̇o2) at the off-transient. CPX also revealed cardiopulmonary impairments following COVID-19. Peak oxygen uptake (V̇o2peak), percent-predicted V̇o2peak, and V̇o2 at the ventilatory threshold (V̇o2VT) were reduced by 17%, 17%, and 12% in COVID-19 survivors, respectively (all P < 0.05). None of the ventilatory parameters differed between groups (all P > 0.05). In addition, COVID-19 survivors also presented with blunted chronotropic responses (i.e., chronotropic index, maximum heart rate, and heart rate recovery; all P < 0.05). These findings suggest that COVID-19 negatively affects central (chronotropic) and peripheral (metabolic) factors that impair the rate at which V̇o2 is adjusted to changes in energy demands.NEW & NOTEWORTHY Our findings provide novel data regarding the impact of COVID-19 on submaximal and maximal cardiopulmonary responses to exercise. We showed that V̇o2 kinetics is significantly impaired at both the onset (on-transient) and the recovery phase (off-transient) of exercise in these patients. Furthermore, our results suggest that survivors of severe COVID-19 may have a higher metabolic demand at a walking pace. These findings may partly explain the exertional intolerance frequently observed following COVID-19.

Effects of short sprint interval training on aerobic and anaerobic indices: A systematic review and meta-analysis.

The effects of short sprint interval training (sSIT) with efforts of ≤10 s on maximal oxygen consumption (V̇O2 max), aerobic and anaerobic performances remain unknown. To verify the effectiveness of sSIT in physically active adults and athletes, a systematic literature search was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). The databases PubMed/MEDLINE, ISI Web of Science, and SPORTDiscus were systematically searched on May 9, 2020, and updated on September 14, 2021. Inclusion criteria were based on PICO and included healthy athletes and active adults of any sex (≤40 years), performing supervised sSIT (≤10 s of "all-out" and non-"all-out" efforts) of at least 2 weeks, with a minimum of 6 sessions. As a comparator, a non-sSIT control group, another high-intensity interval training (HIIT) group, or a continuous training (CT) group were required. A total of 18 studies were deemed eligible. The estimated SMDs based on the random-effects model were -0.56 (95% CI: -0.79, -0.33, p < 0.001) for V̇O2 max, -0.43 (95% CI: -0.67, -0.20, p < 0.001) for aerobic performance, and -0.44 (95% CI: -0.70, -0.18, p < 0.001) for anaerobic performance after sSIT vs. no exercise/usual training. However, there were no significant differences (p > 0.05) for all outcomes when comparing sSIT vs. HIIT/CT. Our findings indicate a very high effectiveness of sSIT protocols in different exercise modes (e.g., cycling, running, paddling, and punching) to improve V̇O2 max, aerobic, and anaerobic performances in physically active young healthy adults and athletes.

Acute affective responses to high-intensity interval exercise: Implications on the use of different stimulus-recovery amplitudes.

The effect of high-intensity interval exercise (HIIE) on affective responses is unclear due to the several variables of HIIE, which may be minimized by using derived variables (e.g. amplitude). The amplitude reflects the difference between stimulus and recovery intensities, being more representative of the physiological changes than central tendency variables such as average intensity. This study aimed to compare the affective responses in HIIE sessions in different amplitudes with a vigorous-intensity continuous exercise (VICE) session. Eleven participants completed five sessions. The peak oxygen consumption (VO2Peak) and peak power (Wpeak) were measured. Participants performed one VICE and three HIIE sessions (10x[1min-90%WPeak/1min-50%WPeak]; 10x[1min-100%WPeak/1min-40%WPeak]; and 10x[1min-110%WPeak/1min-40%WPeak]). The exercise sessions were performed at the same average intensity (70%WPeak) and duration (20 min). The Feeling Scale (FS) was applied in each minute throughout the exercise sessions. Regarding the FS responses, a two-way repeated-measures ANOVA showed no significant interaction for FS (P=0.093) or main effect for condition (P=0.206) and time (P=0.078), indicating that irrespective of the amplitude of the HIIE, FS results were similar between conditions. The effect size (ES) analysis showed a small effect in favour of HIIE-90/50 (ES=0.30) and HIIE-100/40 (ES=0.26) and a null effect on HIIE-110/30 (ES=0.08) when compared to VICE. Chi-squared analysis showed no significant differences between conditions in the number of participants that reduced, maintained, or increased the FS from pre-exercise to last stimulus and recovery indicating a high variability of the affective responses. HIIE sessions provide similar affective responses when performed at the same average intensity, even with different amplitudes.Highlights HIIE amplitude reflects the difference between stimulus and recovery intensities and seems not to modulate the affective responses to HIIE sessions configured with different amplitudes.HIIE sessions performed at the same average intensity and different amplitudes result in similar affective responses.High inter-individual variability of affective responses occurs in HIIE sessions configured based on the amplitude.

Determinants of exercise capacity in children and adolescents with severe therapy-resistant asthma.

OBJECTIVE: To evaluate the exercise capacity of children and adolescents with severe therapy resistant asthma (STRA) aiming to identify its main determinants. METHODS: Cross-sectional study including individuals aged 6-18 years with a diagnosis of STRA. Clinical (age and gender), anthropometric (weight, height and body mass index) and disease control data were collected. Lung function (spirometry), cardiopulmonary exercise testing (CPET) and exercise-induced bronchoconstriction (EIB) test were performed. RESULTS: Twenty-four patients aged 11.5 ± 2.6 years were included. The mean forced expiratory volume in one second (FEV1) was 91.3 ± 9.2%. EIB occurred in 54.2% of patients. In CPET, the peak oxygen uptake (VO2peak) was 34.1 ± 7.8 mL kg-1 min-1. A significant correlation between ventilatory reserve and FEV1 (r = 0.57; p = 0.003) was found. Similarly, there was a significant correlation between CPET and percent of FEV1 fall in the EIB test for both VE/VO2 (r = 0.47; p = 0.02) and VE/VCO2 (r = 0.46; p = 0.02). Patients with FEV1<80% had lower ventilatory reserve (p = 0.009). In addition, resting heart rate correlated with VO2peak (r=-0.40; p = 0.04), VE/VO2 (r = 0.46; p = 0.02) and VE/VCO2 (r = 0.48; p = 0.01). CONCLUSIONS: Exercise capacity is impaired in approximately 30% of children and adolescents with STRA. The results indicate that different aspects of aerobic fitness are influenced by distinct determinants, including lung function and EIB.

Cardiopulmonary exercise testing in neuromuscular disease: a systematic review.

INTRODUCTION: Cardiopulmonary exercise testing (CPET) is increasingly used to determine aerobic fitness in health and disability conditions. Patients with neuromuscular diseases (NMDs) often present with symptoms of cardiac and/or skeletal muscle dysfunction and fatigue that might impede the ability to deliver maximal cardiopulmonary effort. Although an increasing number of studies report on NMDs' physical fitness, the applicability of CPET remains largely unknown. AREAS COVERED: This systematic review synthesized evidence about the quality and feasibility of CPET in NMDs and patient's aerobic fitness. The review followed the PRISMA guidelines (PROSPERO number CRD42020211068). Between September and October 2020 one independent reviewer searched the PubMed/MEDLINE, EMBASE, SCOPUS, and Web of Science databases. Excluding reviews and protocol description articles without baseline data, all study designs using CPET to assess adult or pediatric patients with NMDs were included. The methodological quality was assessed according to the American Thoracic Society/American College of Chest Physicians (ATS/ACCP) recommendations. EXPERT OPINION: CPET is feasible for ambulatory patients with NMDs when their functional level and the exercise modality are taken into account. However, there is still a vast potential for standardizing and designing disease-specific CPET protocols for patients with NMDs. Moreover, future studies are urged to follow the ATS/ACCP recommendations.

Cardiorespiratory Fitness and Performance in Multiple Domains of Executive Functions in School-Aged Adolescents.

The objective of this study was to investigate the association between cardiorespiratory fitness (CRF) and performance in multiple domains of executive functions in school-aged adolescents. A sample of 132 adolescents (43% girls) aged 11-16 years were included in this cross-sectional study. Each participant completed a progressive aerobic cardiovascular endurance running (PACER) test, computerized cognitive tasks (Attentional Network, Berg's Card Sorting, Go/No-Go oddball, Sternberg's Working Memory, and Tower of London) and questionnaire for daytime sleepiness, as well as other factors that might influence cognitive performance (age, sex, school year, pubertal stage, and body mass index - BMI). Generalized linear model was used to calculate the coefficient estimates (ß) and its 95% confidence interval (CI) for the cognitive tasks using PACER laps as a predictor, controlling for potential confounding variables. There was a negatively association of PACER laps with planning (ß = -17.1, 95% CI -31.9, -2.3) and solution (ß = -44.6, 95% CI -75.1, -14.2) time in performing the Tower of London task, as well as with perseverative errors in performing Berg's task (ß = -0.073, 95% CI -0.133, -0.013). Moderating effect of sex was found for the association of PACER laps with completed categories and perseverative errors in Berg's task (p < 0.05). Mediating effect of BMI was found for the association between PACER laps and NoGo task, revealing a full mediator accounted for 81% of the total effect mediated (standardized indirect effect, -0.069, 95% CI -0.140, -0.020; standardized direct effect, 0.011, 95% CI -0.149, 0.165). No association was found for Attentional or Sternberg's tasks. The findings suggest that school-aged adolescents with higher CRF level showed better planning and problem-solving abilities and cognitive flexibility. Additionally, the positive association of CRF with cognitive flexibility was sex-moderated and with inhibitory control was BMI-mediated.

Clustering of 24-h movement behaviors associated with cardiorespiratory fitness among adolescents: a latent class analysis.

This study aimed to examine the clustering of 24-h movement behaviors (moderate to vigorous physical activity, screen time, and sleep duration) and their association with cardiorespiratory fitness among adolescents. We evaluated 561 adolescents (52.1% girls; mean age, 13.0 ± 1.0 years) from Florianópolis, Brazil. A 20-m shuttle run was used to assess cardiorespiratory fitness, while a questionnaire was used to measure 24-h movement behaviors. A latent class analysis was performed to identify the clustering of 24-h movement behaviors, while linear Bayesian mixed-effect regression models were applied to identify their association with cardiorespiratory fitness. Two classes were identified: unhealthy (10.4%), characterized as a high probability of practicing less than 300 min/week of moderate to vigorous physical activity, spending more than 4 h/day in front of screens, and sleeping less than 8 h/day; and healthy (89.6%), characterized by a high probability of practicing more than 420 min/week of moderate to vigorous physical activity, spending less than 2 h/day in front of screens, and sleeping 8-10 h/day. Adolescents in the healthy class had a higher cardiorespiratory fitness level than those in the unhealthy class. Most adolescents were grouped in the healthy class and had higher cardiorespiratory fitness levels than those in the unhealthy class. These results suggest that families and professionals should work toward creating healthier lifestyles for adolescents by increasing opportunities to practice moderate to vigorous physical activity, reduce screen time, and favor healthy sleep to increase their cardiorespiratory fitness levels. What is Known: • Moderate to vigorous physical activity, screen time, and sleep duration are positively, negatively, and inconsistently associated with cardiorespiratory fitness, respectively, when analyzed separately. • Little is known about the clustering of 24-h movement behaviors and how they are associated with cardiorespiratory fitness levels in adolescents. What is New: • The 24-h movement behaviors clustered into almost opposite classes among adolescents (healthy and unhealthy classes). • Adolescents in the healthy class had greater cardiorespiratory fitness levels than those in the unhealthy class.

How do swimmers pace the 400 m freestyle and what affects the pacing pattern?

To describe the pacing pattern of elite 400 m freestyle swimmers, understand how athletes select the first half compared to their 200-m race pace, and correlate critical speed (CS) and D' with pacing parameters. The best all-time 400 m performances were obtained, and 200 m performances were retrieved from the same competition. Twenty-four performances were selected and, when possible, 50 m-splits were obtained. CS and D' were calculated based on the 200 m and 400 m performances. Most athletes adopted a parabolic pacing pattern. Performance in the 400 m correlated with that of the 200 m (rho = 0.418, p = 0.042), the % difference between 200 m performance and 200 m split correlated with CS (rho = -0.595, p = 0.002) and with D' (rho = 0.808, p < 0.001). The correlation between D' and % difference between average speed and CS was nearly perfect (rho = 1.000, p < 0.001). Recommendations of having the first half of the 400 m 4-5 s slower than their 200 m race do not seem to be appropriate for all swimmers and depends on physiological abilities.

Aerobic Exercise-Induced Changes in Cardiorespiratory Fitness in Breast Cancer Patients Receiving Chemotherapy: A Systematic Review and Meta-Analysis.

While performing aerobic exercise during chemotherapy has been proven feasible and safe, the efficacy of aerobic training on cardiorespiratory fitness (CRF) in women with breast cancer undergoing chemotherapy has not yet been systematically assessed. Therefore, the objective of this work was to determine (a) the efficacy of aerobic training to improve CRF; (b) the role of aerobic training intensity (moderate or vigorous) on CRF response; (c) the effect of the aerobic training mode (continuous or interval) on changes in CRF in women with breast cancer (BC) receiving chemotherapy. A systematic review and meta-analysis were conducted as per PRISMA guidelines, and randomized controlled trials comparing usual care (UC) and aerobic training in women with BC undergoing chemotherapy were eligible. The results suggest that increases in CRF are favored by (a) aerobic training when compared to usual care; (b) vigorous-intensity aerobic exercise (64-90% of maximal oxygen uptake, VO2max) when compared to moderate-intensity aerobic exercise (46-63% of VO2max); and (c) both continuous and interval aerobic training are effective at increasing the VO2max. Aerobic training improves CRF in women with BC undergoing chemotherapy. Notably, training intensity significantly impacts the VO2max response. Where appropriate, vigorous intensity aerobic training should be considered for women with BC receiving chemotherapy.

A capacidade preditiva de indicadores de composicao corporal, aptidao aeróbia e coordenacao motora sobre a atencao e funcao executiva em criancas de 6 a 11 anos / The predictive capacity of anthropometric indicators, body composition, aerobic fitness and motor coordination on the performance of attention and executive function in children aged 6 to 11 years

Verificar a associação e indicadores de predição do desempenho atencional e função executiva frente as variáveis antropométricas, aeróbias e motoras de crianças. Participaram do estudo 351 estudantes com idades entre 6 a 11 anos, alunos de três escolas, duas da rede privada e uma pública situadas no Distrito Federal. Os pesquisadores realizaram 3 visitas para aplicação dos instrumentos de pesquisa, realizados de forma randomizada, sendo determinadas por sorteios. Os instrumentos de pesquisa foram aplicados dentro das dependências da escola, divididos em três blocos: 1) teste de atenção por cancelamento e teste de trilhas A e B (aplicados de forma coletiva); 2) testes de capacidade aeróbia Intermittent Recovery Test ­ level 1 (Yo-Yo); 3) anamnese, composição corporal e o teste Körperkoordination für Kinder (KTK). A competência motora ≥70,5 e ≥69,45 escores mostrou-se preditora da atenção (área=0,63; IC=0,55-0,70) e função executiva (área=0,86; IC=0,82-0,90), respectivamente e estes indicadores representam 2,52 e 8,41 vezes mais chances de acontecerem em comparação as crianças que obtiveram menor valores de escore motor. A circunferência da cintura apresentou-se como um bom preditor da atenção (área=0,68; IC=0,61-0,76), e função executiva (área=0,61; IC=0,53-0,58), desta forma, as crianças com circunferência da cintura ≤ 63,5 e ≤ 69,5 apresentaram uma proporção de 60 a 28% maior de chances de alcançarem maiores valores de atenção e função executiva respectivamente. O percentual de gordura corporal também demonstrou capacidade de preditiva da atenção (≤27,7% área=0,61; IC=0,53-0,68) e função executiva (≤25,8% área=0,62; IC=0,5 6-0,69). A circunferência da cintura, percentual de gordura corporal e coordenação motora destacaram-se por apresentarem capacidade preditiva sobre o desempenho da atenção e FE. Ademais, a co ordenação motora e circunferência da cintura podem ser utilizadas como indicadores de risco ou performance daatenção e FE em crianças de 6 a 11 anos....(AU)

Similar maximal oxygen uptake assessment from a step cycling incremental test and verification tests on the same or different day.

The present study aimed to compare maximal oxygen uptake of a step incremental test with time to exhaustion verification tests (TLIM) performed on the same or different day. Nineteen recreationally trained cyclists (age: 23 ± 2.7 years; maximal oxygen uptake: 48.0 ± 5.8 mL·kg-1·min-1) performed 3 maximal tests as follows: (i) same day: an incremental test with 3-min stages followed by a TLIM at 100% of peak power output of the incremental test (TLIM-SAME) interspaced by 15 min; and (ii) different day: a TLIM at 100% of peak power output of the incremental test (TLIM-DIFF). The maximal oxygen uptake was determined for the 3 tests. The maximal oxygen uptake was not different among the tests (incremental: 3.83 ± 0.41; TLIM-SAME: 3.72 ± 0.42; TLIM-DIFF: 3.75 ± 0.41 L·min-1; P = 0.951). Seven subjects presented a variability greater than ±3% in both verification tests compared with the incremental test. The same-day verification test decreased the exercise tolerance (240 ± 38 vs. 310 ± 36 s) compared with TLIM-DIFF (P < 0.05). In conclusion, the incremental protocol is capable of measuring maximal oxygen uptake because similar values were observed in comparison with verification tests. Although the need for the verification phase is questionable, the additional tests are useful to evaluate individual variability. Novelty Step incremental test is capable of measuring maximal oxygen uptake with similar values during TLIM on the same or different day. Although the necessity of the verification phase is questionable, it can allow the determination of variability in maximal oxygen uptake.

Use of the anaerobic speed reserve to normalize the prescription of high-intensity interval exercise intensity.

The aim of this study was to compare the perceptual and physiological responses and time-to-exhaustion in high intensity interval exercise (HIIE) protocols that are prescribed based on the relative anaerobic speed reserve (ASR) or maximal aerobic speed (MAS) in athletes with different ASR values, as well as the coefficient of variation (CV) of the abovementioned variables. Eleven long-distance runners and ten rugby players were submitted to five experimental sessions on different days; the first and second session were intended for the determination of the anthropometry, MAS and maximal sprint (MSS). In the subsequent sessions, three HIIE15:15s protocols were performed until exhaustion (110%MAS, Δ25%ASR, and Δ50%ASR) in random order. The anthropometric characteristics and variables obtained from the MAS and MSS tests in the different groups were compared by Student's unpaired t-test. The analysis of mixed models for repeated measures (groups and protocols) was used to compare the speed, delta blood lactate, rating of perceived exertion, and time-to-exhaustion. Rugby players presented higher ASR (13.6 ± 0.9 km h-1) compared to long-distance runners (12.6 ± 0.9 km h-1) (P = .049). For the HIIE15:15s protocols, there were no protocol and group interaction effects. However, lower CV values were observed for time-to-exhaustion (a mean reduction of 52%) and delta blood lactate (a mean reduction of 48%) in Δ25%ASR and Δ50%ASR when compared to 110%MAS. Furthermore, the rating of perceived exertion CV was similar in all HIIE15:15s protocols. The prescription of intensity of HIIE based on the ASR was able to reduce the inter-subject variability of lactate and time-to-exhaustion in rugby players and long-distance runners.

Independent and Combined Effects of Biological Maturation and aerobic performance on the gross motor coordination in prepubertal girls

ABSTRACT The present study analyzed the effect of biological maturation on the performance in the test of gross motor coordination in girls, before and after having its effect controlled by body mass index (BMI) and aerobic performance. The sample was composed by 63 pre-pubertal girls (8.0-8.99 years). The girls who were less advanced in biological maturation presented lower body size and better physical performance in the tasks of walking backward on balance beams (t=2.706; p<0.01; d=0.70), moving sideways on boxes (t=2.128; p<0.05; d=0.48), hopping for height on one leg (t=2.076, p<0.05; d=0.54) and 20-m shuttle run (t=3.162; p <0.05; d=0.61). The maturation no longer influenced performance in the tasks of gross motor coordination when considering BMI and aerobic fitness.

RESUMO O presente estudo analisou o efeito da maturação biológica no desempenho em teste de coordenação motora grossa de meninas, antes e depois de ter seu efeito controlado pelo índice de massa corporal (IMC) e pelo desempenho aeróbio. Participaram 63 meninas pré-puberes de 8,0 a 8,99 anos. As meninas menos avançadas na maturação biológica apresentaram menores dimensões corporais e melhores desempenhos físicos nas tarefas de equilíbrio à retaguarda (t=2,706; p<0,01; d=0,70), transposição lateral (t=2,128; p<0,05; d=0,48), saltos monopedais (t=2,076; p<0,05; d=0,54) e 20-m shuttle run (t=3,162; p<0,05; d=0,61). A maturação deixou de influenciar o desempenho nas tarefas de coordenação motora grossa quando levou-se em consideração o IMC e a aptidão aeróbia.

RESUMEN El presente estudio analizó el efecto de la maduración biológica sobre el desempeño en prueba de coordinación motora gruesa de niñas, antes y después de tener su efecto controlado por el índice de masa corporal (IMC) y por el desempeño aeróbico. Participaron del estudio, 63 niñas pre-puberes de 8 años. Las niñas menos avanzadas en la maduración biológica presentaron menores dimensiones corporales y mejores desempeños físicos en las tareas de equilibrio a la retaguardia (t=2,706; p<0,01; d=0,70), transposición lateral (t=2,128; p<0,05; d=0,48), saltos monopedales (t=2,076; p<0,05; d=0,54) y 20-m shuttle run (t=3,162; p<0,05; d=0,61). La maduración dejó de influenciar el desempeño en las tareas de coordinación motora gruesa cuando se tuvo en cuenta el IMC y la aptitud aerobia.

Blood glucose threshold determination is stage length dependent

Aim: This study aimed to verify whether different stage length affects the intensity of the Blood Glucose Threshold (BGT), and the agreement between evaluators for BGT determination. Methods: Fourteen subjects attended the laboratory during the first session to perform anthropometric measures and become familiar with procedures. In the following three sessions, subjects performed an incremental test on the ergometer bicycle and in each test a different protocol was performed in randomized order (1, 3- and 5-min stage) to identify BGT. Three different evaluators determined the BGT. Results: Our data show that the BGT is stage length-dependent (1, 3- and 5-min; P<0.0001). The intraclass correlation coefficient showed that there was a strong correlation among evaluators for all protocols (ICC = 0.8 to 1 min; ICC = 0.8 to 3 min; and ICC 0.9 to 5 min). However, one evaluator determined the BGT at a higher intensity than others. The peak load was lower at long stage length. Conclusion: We concluded that stage length influences the BGT intensity determination. The BGT presents a good agreement among evaluators. However, a minimum of two evaluators is needed for BGT determination. The peak load is affected by stage length.(AU)

Health-related physical fitness and weight status in 13- to 15-year-old Latino adolescents. A pooled analysis / Aptidão física relacionada à saúde e status do peso em adolescentes latinos de 13 a 15 anos de idade. Uma análise em conjunto

Abstract Objective: The aim of this study was to investigate the relation between health-related physical fitness and weight status in 13- to 15-year-old Latino adolescents. Method: The final sample consisted of 73,561 adolescents aged 13 -15 years (35,175 girls) from Chile (n = 48,771) and Colombia (n = 24,790). Cardiorespiratory and musculoskeletal fitness were measured using 20-m shuttle run (relative peak oxygen uptake - VO2peak) and standing broad jump test (lower body explosive strength), respectively. The International Obesity Task Force definition was used to define weight status (i.e., underweight, normal weight, overweight, and obese). Results: The present study found an inverted J-shape relationship between body mass index, cardiorespiratory fitness, and musculoskeletal fitness in both genders and all age groups (p < 0.01). Results also suggest that underweight adolescents, and not just overweight and obese adolescents, have lower odds of having a healthy cardiorespiratory fitness (based on new international criterion-referenced standards) profile when compared with their normal weight peers, except in girls aged 14 (p = 0.268) and 15 years (p = 0.280). Conclusions: The present results indicate low cardiorespiratory fitness and musculoskeletal fitness levels in underweight, overweight, and obese adolescents when compared with their normal weight peers. The findings appear to suggest that exercise programs should to decrease fat mass in overweight/obese adolescents and increase muscle mass in underweight adolescents.

Resumo Objetivo: Investigar a relação entre a aptidão física relacionada à saúde e o status do peso em adolescentes latinos de 13 a 15 anos. Método: A amostra final consistiu em 73.561 adolescentes entre 13 e 15 anos (35.175 meninas) do Chile (n = 48.771) e da Colômbia (n = 24.790). As aptidões cardiorrespiratória e musculoesquelética foram medidas com a corrida vaivém de 20 m (consumo máximo de oxigênio relativo - VO2máx.) e o teste de impulso horizontal (menor força explosiva do corpo), respectivamente. A definição Força-Tarefa Internacional de Obesidade foi usada para definir o status do peso (ou seja, abaixo do peso, peso normal, sobrepeso e obeso). Resultados: O presente estudo encontrou uma relação na forma de J invertido entre o índice de massa corporal, a aptidão cardiorrespiratória e a aptidão musculoesquelética em ambos os sexos e em todas as faixas etárias (p < 0,01). Os resultados também sugerem que os adolescentes abaixo do peso e não somente os adolescentes acima do peso e obesos têm menor chance de ter um perfil de aptidão cardiorrespiratória saudável (com base em novos padrões internacionais referenciados a critério) em comparação com os pares com peso normal, exceto em meninas de 14 (p = 0,268) e 15 anos (p = 0,280). Conclusões: Nossos resultados mostram baixos níveis de aptidão cardiorrespiratória e aptidão musculoesquelética em adolescentes abaixo do peso, acima do peso e obesos em comparação com os pares com peso normal. Os achados parecem sugerir que os programas de exercícios devam ser voltados para reduzir a massa gorda em adolescentes com sobrepeso/obesos e aumentar a massa muscular em adolescentes abaixo do peso.

Housing conditions modulate spontaneous physical activity, feeding behavior, aerobic running capacity and adiposity in C57BL/6J mice.

There is evidence of reduced adiposity in rodents living in a large cages (LC) as compared to animals housed in small cages (SC). Because spontaneous physical activity (SPA) provides an important portion of the total daily energy expenditure, an increase of SPA in rodents kept in LC could explain their reduced body fat accumulation. The relationship between SPA and components of physical fitness (i.e. aerobic and anaerobic fitness and body leanness) has not been previously determined. We examined the effects of eight weeks of LC exposure on SPA, body composition, feeding behavior, as well as aerobic and anaerobic running capacity in adult C57BL/6J mice. Male mice were housed in cages of two different sizes for 8 weeks: a small (SC, n = 10) and large (LC n = 10) cages with 1320 cm2 and 4800 cm2 floor space, respectively. SPA was measured gravimetrically, and food and water intake were recorded daily. Mice had critical velocity (CV) and anaerobic running capacity (ARC) evaluated at the beginning, middle course (4th week) and at the end of study (8th week). Despite non-significant differences in each week LC-mice were more active than SC-mice by considering all SPA values obtained in the entire period of 8 weeks. The difference in SPA over the whole day was mainly due to light phase activity, but also due to activity at dark period (from 6 pm to 9 pm and from 5 am to 6 am). LC-mice also exhibited higher food and water intake over the entire 8-wk period. LC-mice had lower content of fat mass (% of the eviscerated carcass) than SC-mice (SC: 8.4 ±â€¯0.4 vs LC: 6.3 ±â€¯0.3, p < 0.05). LC-mice also exhibited reduced epididymal fat pads (% of body mass) compared to SC-mice (SC: 1.3 ±â€¯0.1 vs LC: 0.9 ±â€¯0.1, p < 0.05) and retroperitoneal fat pads (SC: 0.4 ±â€¯0.05 vs LC: 0.2 ±â€¯0.02, p < 0.05). The LC-group showed significantly higher critical velocity than SC-group at the fourth week (SC: 14.9 ±â€¯0.6 m·min-1 vs LC: 18.0 ±â€¯0.3 m·min-1, p < 0.05) and eighth week (SC: 17.1 ±â€¯0.5 m·min-1 vs LC: 18.8 ±â€¯0.6 m·min-1, p < 0.05). Our findings demonstrate that eight weeks of LC housing increases SPA of C57BL/6J mice, and this may lead to reduced fat accumulation as well as higher aerobic fitness. Importantly, our study implies that SC limits SPA, possibly generating experimental artifacts in long-term rodent studies.

A Randomized Controlled Trial Investigating the Effects of Undulatory, Staggered, and Linear Load Manipulations in Aerobic Training on Oxygen Supply, Muscle Injury, and Metabolism in Male Recreational Runners.

BACKGROUND: Taper is considered as a strategy to avoid overtraining and increase peak performance in athletes. Because aerobic exercise increases the level and duration of independence during the lifespan, the participation of recreational athletes has increased in running events around the world. However, the effects of using load reduction in their training and aerobic performance are still not well known. OBJECTIVES: Our goal was to compare load manipulations, using tapering-like periods in the end of recreational athletes training evaluating alterations in oxygen supply, muscle injury, and metabolism markers. METHODS: Healthy males (n = 88, 20-35 years old) were randomly distributed in groups using a combination of two mesocycles of 4 weeks, undulatory and staggered, with two daily microcycles, undulatory and linear. Undulatory-undulatory (Und-Und) and undulatory-linear (Und-Lin) groups had load reduction in the final week of training while the staggered-undulatory (Sta-Und) and staggered-linear (Sta-Lin) groups did not. Cardiorespiratory capacity (V̇O2max), body mass index (BMI), and body fat % were evaluated. Blood samples were also collected to analyze hematocrit (Ht), mean corpuscular hemoglobin (MCHC), circulating levels of hemoglobin (Hb), creatine kinase (CK), lactate dehydrogenase (LDH), aspartate aminotransferase (AST), alanine aminotransferase (ALT), urea (U), cortisol (C), free testosterone (FT), and free T/C ratio. RESULTS: After 8 weeks of training, Und-Und had the highest trend to increase V̇O2max. Both Und-Und and Sta-Lin reduced body fat %. Und-Und showed a significant increase in MCHC, T and Free T/C ratio, a positive trend to increase Ht% and Hb levels, and a trend to decrease CK, LDH, and C circulating levels. Sta-Lin presented a trend to decrease Ht% and Hb levels, a significant increase in CK, LDH, AST, ALT circulating levels, and a decrease in Free T/C ratio. CONCLUSION: The use of daily undulatory training load provides better gains for aerobic fitness while the use of staggered load, mainly associated with linear load, promotes inadequate recovery in recreational runners.

Associations between cardiorespiratory fitness, physical activity, intraindividual variability in behavior, and cingulate cortex in younger adults.

BACKGROUND: Higher levels of cardiorespiratory fitness (CRF) and greater amounts of physical activity have been associated with lower intraindividual variability (IIV) in executive function in children and older adults. In the present study, we examined whether CRF, measured as maximal oxygen uptake (VO2max), and daily volume of moderate-to-vigorous intensity physical activity (MVPA) were associated with IIV of reaction time during performance of the incongruent condition of the Stroop task in younger adults. Further, we examined whether the thickness of the cingulate cortex was associated with regulating variability in reaction time performance in the context of CRF or physical activity. METHODS: CRF (measured as VO2max), accelerometry-measured MVPA, Stroop performance, and thickness of the rostral anterior cingulate cortex (rACC) derived from magnetic resonance imaging data were collected in 48 younger adults (age = 24.58 ± 4.95 years, mean ± SD). Multiple regression was used to test associations between IIV during the Stroop task and CRF, MVPA, and rACC thickness. Mediation was tested using maximum likelihood estimation with bootstrapping. RESULTS: Consistent with our predictions, higher VO2max was associated with greater rACC thickness for the right hemisphere and greater daily amounts of MVPA were associated with greater rACC thickness for both the left and right hemispheres. Greater thickness of the right rACC was associated with lower IIV for the incongruent condition of the Stroop task. CRF and MVPA were not directly associated with IIV. However, we did find that IIV and both CRF and MVPA were indirectly associated via the thickness of the right rACC. CONCLUSION: These results indicate that higher CRF and greater daily volume of MVPA may be associated with lower IIV during the Stroop task via structural integrity of the rACC. Randomized controlled trials of MVPA would provide crucial information about the causal relations between these variables.