Effectiveness of elastic band training and group-based dance on physical-functional performance in older women with sarcopenia: a pilot study.

BACKGROUND: Sarcopenia is a syndrome associated with aging that causes progressive loss of skeletal muscle mass and muscle function. In this pilot study, we compared the effectiveness of elastic band training regarding group-based dance on fat mass, fat-free mass, handgrip strength (HGS; dominant and non-dominant hand), leg strength, timed up-and-go (TUG) and walking speed in older women with sarcopenia. METHODS: This is a randomized controlled trial, single-blind, repeated measures of parallel groups (elastic band group: EBG, n = 21; group-based dance: GBD, n = 19), and a quantitative methodology. Three 60-minute sessions per week for 12 weeks were dedicated to the interventions with pre- and post-assessments. A two-factor mixed analysis of variance (ANOVA) model with repeated measures was performed to measure the group×time effect. RESULTS: A significant interaction revealed for fat-free mass (F1,16= 18.91; p < 0.001; EBG + 10.9% vs. GBD - 1.97%), HGS dominant hand (F1,16= 7.44; p = 0.014; EBG + 10.9% vs. GBD + 0.59%), HGS non-dominant hand (F1,16= 6.41; p = 0.022; EBG + 10.21% vs. GBD + 3.80%), leg strength (F1,16= 17.98; p < 0.001; EBG + 9.1% vs. GBD + 3.83%), TUG (F1,16= 7.52; p = 0.014; EBG - 14.7% vs. GBD - 1.0%) and walking speed (F1,16 = 6.40; p = 0.019; EBG - 7.6% vs. GBD - 4.35%) in favor of EBG. CONCLUSION: Elastic band training produces significantly greater responses on physical-functional performance regarding group-based dance in older women with sarcopenia. On the other hand, the EBG revealed a significant improvement in fat-free mass and upper and lower limb muscle strength, as well as a significant decrease time in TUG, and walking speed. Elastic band exercise is a safe, easy, affordable, and effective physical activity strategy, according to the findings.

Association between fitness, anthropometric indices and laboratory parameters in elderly women.

BACKGROUND: Aging causes an involution of anthropometric and health indices that can affect physical fitness. AIM: To determine the influence of anthropometric and health indices on the physical fitness of elderly women. MATERIAL AND METHODS: Anthropometric parameters, serum lipids, blood glucose and physical fitness evaluated using Senior Fitness Test, were assessed in 140 women aged 70 ± 5 years. The association between parameters was analyzed using Pearson's correlation coefficient and multiple regression models. RESULTS: In the regression models serum lipids and the suprailiac skinfold were significant predictors of the up and go test (R2= 0.48). HDL cholesterol and the level of physical activity were predictors of the two minutes step test (R2= 0.31). Serum lipids, suprailiac skinfold and age were predictors of the back-scratch test (R2= 0.41). Fasting blood glucose and HDL cholesterol were predictors of the chair sit and reach test (R2= 0.24). Serum lipids and body mass index were predictors of the arm curl test (R2= 0.37). Body mass index and serum lipids were predictors of the chair stand test (R2= 0.49). CONCLUSIONS: Anthropometric variables, serum lipid levels and blood glucose were predictors of different physical fitness parameters in these women.

[Factors associated with low quality of life in Chilean adults during the COVID-19 quarantine]. / Factores asociados a una baja calidad de vida en adultos chilenos durante la cuarentena por COVID-19.

BACKGROUND: The quarantine and social distancing implemented during COVID 19 pandemic may hamper the quality of life of the population. AIM: To determine the factors associated with a low quality of life during COVID 19 quarantine in Chilean adults. MATERIAL AND METHODS: The SF-36 survey about quality of life was answered by 1,082 Chilean adults aged between 18 and 60 years, who were quarantined by the COVID-19 health alert. Other variables studied were sociodemographic background, nutritional status, lifestyles, level of physical activity, sedentary behavior and sleep hours. Risk factors associated with low quality of life were identified by logistic regression analysis for each of the 8 dimensions evaluated in the SF-36 questionnaire. RESULTS: The factors that increased the probability of having a lower general health perception were being female (Odds ratio (OR) = 1.29; p = 0.05), being physically inactive (OR = 2.76 p < 0.01), unhealthy hours of sleep (OR = 1.58, p < 0.01), smoking (OR = 1.59, p < 0.01) and eating junk food (OR = 2.26; p < 0.01). For the other dimensions of quality of life, the most frequently repeated factors were being female, junk food consumption, and being physically inactive and sedentary. CONCLUSIONS: There are factors associated with a low quality of life during the quarantine of the COVID-19 pandemic in the Chilean population. Their identification could reinforce remedial actions at the government level to benefit the health of the population during this health emergency.

Effects of Physical Activity Governmental Programs on Health Status in Independent Older Adults: A Systematic Review.

This systematic review analyzes the evidence of the effects of physical activity governmental programs oriented toward the health of independent older adults. Medline, Web of Science, PsycINFO, and Psychology & Behavioral Sciences Collection databases were used for data mining, and the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols recommendations were followed. Five studies (n = 2,545 participants) fulfilled the established inclusion criteria. The physical activity programs had beneficial effects on the older adults' quality of life, fall risk, activities of daily living, physical activity levels, nutritional risk, body mass index, arterial pressure, resting heart rate, blood glucose, triglycerides, and/or cholesterol, but did not significantly alter their body fat mass percentage. Programs involving diverse physical capacities seem to be more effective for healthy aging. It is recommended that governments start to disseminate the outcomes of these programs within society and the scientific community.

[Levels of physical activity and excess body weight in university students]. / Factores de riesgo asociados a bajo nivel de actividad física y exceso de peso corporal en estudiantes universitarios.

BACKGROUND: University students are considered a vulnerable group due to their adoption of unhealthy diets and lifestyles. AIM: To determine the main risk factors associated with low level of physical activity and excess body weight in university students. MATERIAL AND METHODS: This cross-sectional study included 358 university students from Talca, (53% female). Sociodemographic, academic, health, lifestyle, nutritional status, physical activity and sedentary behavior variables were analyzed by logistic regression. RESULTS: Men were more likely to present excess body weight than women (Odds ratio (OR): 2.16 [95% CI: 1.17-4.01], p = 0.01). Similarly, those with low level of physical activity (OR: 2.13 [95% CI: 1.10-414], p = 0.03), musculoskeletal injuries (OR: 2.43 [95% CI: 1.09-6.34], p = 0.05) and smokers (OR: 2.09 [95% CI: 1.05-4.14], p = 0.04) were more likely to have excess body weight. Individuals with excess body weight (OR: 2.94 [95% CI: 1.31-6.61], p < 0.01), high sedentary behaviors (OR: 2.01 [95% CI: 1.04-4.55], p = 0.04), those who spent more than 7 hours per week studying (OR: 2.11 [95% CI: 1.06-4.66], p = 0.04), and those with presence of musculoskeletal injuries (OR: 1.49 [95% CI: 1.06- 3.66], p = 0.04) were more likely to be physically inactive. In addition, men were 73% less likely to have low physical activity levels compared to women (OR: 0.27 [95% CI: 0.11-0.56], p < 0.01). CONCLUSIONS: University students have several modifiable risk factors associated with low levels of physical activity and excess weight. Healthy lifestyles promotion should modify these risk behaviors.

[An equation to predict maximum oxygen consumption from the six-minute walk test in healthy young adults]. / Ecuación para predecir el consumo máximo de oxígeno a partir de la prueba de caminata de seis minutos en jóvenes sanos.

BACKGROUND: The six-minute walk test (SMWT) is an easy-to-use test that measures walking distance. AIM: To elaborate an equation to estimate the maximum oxygen consumption (VO2 max) using the results of the SMWT. MATERIAL AND METHODS: Forty men and 40 women aged 22.5 ± 2 years, underwent a SMWT to measure the total walked distance and the recovery heart rate (RhR) Also, VO2 max was estimated from the maximal workload achieved in a cyclo-ergometer using the Storer test. A multivariate regression analysis resulted in a prediction equation that was validated with distributional assumptions of normality, independence and homoscedasticity. The limits of concordance of the predictive model were checked with the Bland-Altman diagram. RESULTS: Body mass index (BMI), sex, RhR and total walked distance explained VO2 max variance by 3.4, 73.1, 17.9 and 32.8%, respectively. The prediction equation achieved was VO2 max (ml.min-1) = -3672.585 + (966.472 × Sex [1: female, 2: male]) + (-18.492 X RhR [beats.minute-1]) + (9.191 X Distance [m]) + (87.707 × BMI). The R2 of the equation was 0.91 (p < 0.01). CONCLUSIONS: This equation predicts VO2 max in Chilean university students according to sex, BMI, cardiovascular response and performance in the SMWT.

[Reference values for the senior fitness test in Chilean older women]. / Valores de referencia para la batería de pruebas Senior Fitness Test en mujeres mayores chilenas físicamente activas.

BACKGROUND: The Senior Fitness Test (SFT) is frequently used to assess physical fitness and functional independence in older people. AIM: To establish reference values for the SFT in Chilean physically active older women according to age ranges. MATERIAL AND METHODS: Cross-sectional study that included 1048 Chilean women aged between 60 and 85 years. Chair stand (CS), arm curl (AC), two-min walk (2 min), chair sit-and-reach (CSr), back scratch (BS), and timed up-and-go test (TUG) were evaluated. The reference values are presented in percentiles (p5, p10, p25, p50, p75, p90 and p95) and are distributed age intervals (60-64, 65-69, 70-74, 75-79 and ≥ 80 years). RESULTS: There was a decrease in strength (CS and AC), aerobic resistance (2 min) and flexibility (CSr and BS) along with age, whereas the time required to perform the timed up and go increased along with age. CONCLUSIONS: Physically active older women show a deterioration in physical fitness along with age. These women have higher reference values in CS, AC, 2 min and CSr, and lower in BS and TUG, than those reported abroad for the SFT.

[Association between health anthropometric indexes with physical fitness in physically active elderly women]. / Asociación entre índices antropométricos de salud y condición física en mujeres mayores físicamente activas.

OBJECTIVE: To associate health anthropometric indexes with physical fitness of elderly women (EW) who participate in physical exercise workshops. MATERIALS AND METHODS: 272 Chilean women over 60 years took part in the study. The variables studied were BMI, waist circumference (WC), waist-height index (WHI) and physical fitness (PF). Correlations were made through the Pearson or Spearman coefficient, and bivariate associations using Pearson's Chi-square and the Fisher's exact test, considering p<0.05. RESULTS: 70.8% of the EW were overweight or obese; 68.8% and 96% were at cardiometabolic risk due to their WC and WHI, respectively. Their PF showed equal performance (53.5%) or higher (33.8%) according to their age and gender. Inverse correlations were found between nutritional status and cardiometabolic risk with PF tests (except for agility and dynamic balance [direct]), and direct association with back scratch test. CONCLUSIONS: Excess weight in physically active EW would not affect their physical-functional performance; however, cardiometabolic risk would be inversely associated with motor function.

OBJETIVO: Asociar los índices antropométricos de salud con la condición física de las mujeres mayores (MM) que participan en talleres de ejercicio físico. MATERIAL Y MÉTODOS: Participaron 272 mujeres chilenas mayores de 60 años. Las variables correspondieron al IMC, perímetro de cintura (PC), índice cintura estatura (ICE) y condición física (CF). Se realizaron correlaciones a través del coeficiente de Pearson o Spearman, y asociaciones bivariadas mediante ji cuadrada de Pearson y el test exacto de Fisher, considerando un p<0.05. RESULTADOS: De las MM, 70.8% alcanzó sobrepeso u obesidad; y 68.8% y 96% riesgo cardiometabólico de acuerdo con PC e ICE, respectivamente. Su CF presentó un rendimiento igual (53.5%) o superior (33.8%) según su edad y sexo. Se encontraron correlaciones inversas entre estado nutricional y riesgo cardiometabólico con las pruebas de CF (excepto la agilidad y equilibrio dinámico, en donde la relación fue directa), y asociación directa con juntar manos. CONCLUSIONES: El exceso de peso en MM físicamente activas no afecta su rendimiento físico-funcional; sin embargo, el riesgo cardiometabólico se asocia inversamente con la funcionalidad motriz.

[Association of sedentariness and health promoting lifestyles in older adults]. / Actividad física y perfil de estilos de vida promotores de la salud en adultos mayores chilenos.

Background Part of having healthy lifestyles should be a regular practice of physical activities. Aim To evaluate the association between the practice of physical activity and healthy lifestyles in older people. Material and Methods The Health-Promoting Lifestyle Profile survey was applied to 1688 older people living in the community, aged 72 ± 7 years (61% women). This survey includes questions about regular physical activity. Results Twenty four percent of surveyed participants declared to practice physical activities at least three times per week, without gender differences. Sedentariness increased along with age. There was a negative association between low physical activity and healthy lifestyles (odds ratio (OR): 3.2 confidence intervals (CI): 2.3-4.5). There was also an association between sedentariness and low self-realization (OR 2.4 CI: 1.8-3.3), low responsibility with health (OR 1.6 CI: 1.22.1), low concern about nutrition (OR 1.8 CI: 1.4-2.4), low stress management (OR 2.0 CI: 1.5-2.7) and low interpersonal support (OR 2.0 CI: 1.5-2.6). Conclusions Sedentariness is negatively associated with health promoting lifestyles in this group of older people.

Frailty, Seasonal Sensitivity and Health-related Quality of Life in Older People Living in High Southern Latitudes: a Bayesian Analysis.

Background: In older people, a notable research gap exists regarding the intricate dynamics between frailty, seasonal sensitivity, and health-related quality of life (HRQoL). This study aimed to determine the association between frailty, seasonal sensitivity, and HRQoL in older people from high southern latitudes. Methods: A cross-sectional observational study was conducted. Frailty, seasonal sensitivity, and HRQoL measurements were self-reported by participants through questionnaires. A total of 118 older people were recruited from a local community. The participants were selected through intentional non-probabilistic sampling. Results: The adjusted models showed a trend where lower education was associated with a higher risk of frailty (BF = 0.218). For frailty and HRQoL, we observed a trend suggesting that HRQoL decreases with increasing severity of frailty (BF = 1.76). In addition, we observed a linear effect based on the severity of seasonal sensitivity, meaning that older people with higher perceived severity report a proportional decrease in HRQoL (BF = 6.66). Conclusion: Sociodemographic factors, such as lower education levels, have increased the risk of frailty. At the same time, frailty and seasonal sensitivity perceived severity were associated with a lower HRQoL in older people.

Quadriceps muscle reaction time in obese children.

This study aimed to determine the influence of obesity, according to body mass index (BMI) and fat mass percentage, on quadriceps muscle reaction times. The study utilized a cross-sectional design. The sample size consisted of 42 schoolchildren (54.5% girls) aged 11 to 12 years old. Participant measurements included weight and height, which were used to categorize individuals based on BMI. Additionally, the electrical bioimpedance technique was employed to categorize participants based on their body fat percentage. A sudden destabilization test of the lower limb was performed to assess the reaction time of the rectus femoris, vastus medialis, and vastus lateralis muscles. The results show that overweight/obese children have a longer muscle reaction time for both the rectus femoris (ß = 18.13; p = 0.048) and the vastus lateralis (ß = 14.51; p = 0.042). Likewise, when the children were classified by percentage of body fat the results showed that overfat/obese children have a longer muscle reaction time for both the rectus femoris (ß = 18.13; p = 0.048) and the vastus lateralis (ß = 14.51; p = 0.042). Our results indicate that BMI and fat mass classification negativity alter the muscle reaction time in children. Overweight/obese or overfat/obese children showed longer reaction times in the rectus femoris and vastus lateralis muscles compared to children with normal weight. Based on these findings, it is suggested that in overweight and obese children, efforts not only focus on reducing body weight but that be complemented with training and/or rehabilitation programs that focus on preserving the normal physiological function of the musculoskeletal system.

Obesity as a Risk Factor for Complications and Mortality in Individuals with SARS-CoV-2: A Systematic Review.

This systematic review aimed to analyze the available studies that identified overweight and/or obesity as a risk factor for mortality, use of respiratory support, and changes in biochemical markers in adults hospitalized with SARS-CoV-2. The PubMed, Web of Science, and Scopus databases were searched using PRISMA guidelines until January 2024. The protocol was registered with PROSPERO (code: CRD42024501551). Of the 473 articles, only 8 met the inclusion criteria (e.g., adult individuals aged 18 or over diagnosed with COVID-19 individuals with overweight and/or obesity). In addition, the Downs and Black tool was used to assess the quality of the studies. The studies analyzed totaled 9782 adults hospitalized for COVID-19, indicating that overweight and obesity are present in more than half of adults. Diseases such as diabetes mellitus and hypertension are more prevalent in adults with obesity. The systematic review also highlighted that a higher incidence of respiratory support is related to a higher incidence of hospitalization in intensive care units and that adults with overweight and obesity have a higher risk of mortality from COVID-19. Biochemical markers such as procalcitinin, C-reactive protein, and interleukin-6 are associated with the severity of COVID-19 infection. This systematic review exposed overweight and/or obesity as a risk factor for worse COVID-19 disease, as well as for the need for intensive care, respiratory support, mortality, and changes in essential blood markers.

Effects of active exergames on physical performance in older people: an overview of systematic reviews and meta-analysis.

This overview assessed the available body of published peer-reviewed systematic reviews and meta-analyses related to the effects of active exergames compared with active/passive control on physical performance outcomes in older people. The methodological quality and certainty of evidence were assessed using PRISMA, AMSTAR 2, and GRADE. The protocol was registered in PROSPERO (code: CRD42023391694). The main outcomes indicate that 4,477 records, five systematic reviews, and 10 meta-analyses were included. The AMSTAR-2 reported six meta-analyses with high methodological quality, four moderate quality, two systematic reviews with low quality, and three very-low quality. Meta-analysis was performed on balance using the Berg Balance Scale (BBS) and Timed Up-and-Go (TUG) tests, on cardiorespiratory fitness using the 6-min walk test, and on upper and lower limbs muscle strength using the handgrip strength, knee extension, and 30-s chair stand tests. Significant differences in favor of the active exergames groups concerning active/passive groups were reported in BBS (SMD = 0.85; 95% CI = 0.12-1.58; I2 = 96%; p = 0.02), TUG (SMD = 1.44; 95% CI = 0.71-2.16; I2 = 97%; p < 0.0001), and 30-s chair stand test (SMD = 0.79; 95% CI = 0.33-1.25; I2 = 88%; p = 0.0008). However, no significant differences were reported in favor of the active exergames groups in 6-min walk (SMD = 0.93; 95% CI = -0.64 to 2.50; I2 = 95%; p = 0.24), handgrip strength (SMD = 0.67; 95% CI = -0.04 to 1.38; I2 = 84%; p = 0.06), and knee extension tests (SMD = 0.20; 95% CI = -0.05 to 0.44; I2 = 95%; p = 0.12) compared to active/passive control. However, it was impossible to perform a meta-analysis for the variables of walking speed as a fall risk due to the diversity of instruments and the small number of systematic reviews with meta-analysis. In conclusion, interventions utilizing active exergames have shown significant improvements in the static and dynamic balance and lower limb muscle strength of apparently healthy older people, compared to control groups of active/inactive participants, as measured by BBS, TUG, and 30-s chair stand tests. However, no significant differences were found in the 6-min walk, HGS, and knee extension tests. Systematic review registration: PROSPERO, CRD42023391694.

The Mediating Role of Cardiorespiratory Fitness in the Association between a Negative Lifestyle and Poor Mental Health in Chilean Schoolchildren.

BACKGROUND: A negative lifestyle has a reported relationship with psychological problems and deteriorated well-being. However, there is little information regarding the mediating role of cardiorespiratory fitness (CRF) in this relationship. OBJECTIVES: The objectives of the present study are twofold: first, to investigate the association between negative lifestyle, physical self-concept (PSC), and depression, and second, to assess the potential mediating role of CRF in this complex relationship. METHODS: This cross-sectional study included 612 schoolchildren aged between 9 and 14 years from the Araucanía region (southern Chile). CRF was measured using the Leger test, and lifestyle, depression, and PSC were measured using validated questionnaires. RESULTS: A negative lifestyle reported an inverse association with PSC (p < 0.001) and a positive association with depression levels (p < 0.001). The mediation analysis showed that CRF was positively related to PSC (p < 0.001) and inversely related to depression (p = 0.001); besides, the indirect effect CRF acted as a partial mediator in the association between a negative lifestyle and PSC (indirect effect = -1.15; SE = 0.01; 95% CI, -1.87, -0.55) and depression levels (indirect effect = 0.22; SE = 0.08; 95% CI, 0.08, 0.38). CONCLUSION: In conclusion, CRF in schoolchildren played a potential mediating role in the association between a negative lifestyle and depression and PSC.

Effects of combat sports on cognitive function in older people: a systematic review.

INTRODUCTION: This systematic review aimed to analyze the available body of published peer-reviewed studies on the effects of combat sports compared with active/passive control on cognitive function and electrophysiological markers of brain activity in older people. EVIDENCE ACQUISITION: The studies were searched in Scopus, Web of Science, PubMed, MEDLINE, and PsycINFO databases from deadline to June 2023. The PRISMA, TESTEX, RoB, and GRADE scales assessed the evidence's methodological quality and certainty of evidence. The protocol was registered in PROSPERO (code: CRD42022361695). EVIDENCE SYNTHESIS: After reviewing 3768 studies, seven combat sports interventions (score ≥60% in methodological quality) were selected, composed of 381 older people (63% female), with a mean age of 66 years. In the selected studies, interventions based on judo, karate, and taekwondo were carried out, where it was not possible to verify the benefits of combat sports in cognitive function and electrophysiological markers of brain activity regarding active/passive control groups, although the individual results of the analyzed studies indicate that the practice of combat sports favor selective attention, divided attention, executive function, visual perception, and cognitive processing speed in older people. CONCLUSIONS: The available evidence does not allow a definite recommendation regarding combat sports as an effective cognitive function intervention in older people.

Effectiveness of an Ecological Model-Based Active Transport Education Program on Physical and Mental Health in High School Students (MOV-ES Project): Study Protocol for a Randomized Controlled Trial.

The United Nations, through its 2030 Agenda and Sustainable Development Goals, advocates for the establishment of conducive environments for physical activity, following the ecological model. In line with this initiative, active transportation emerges as an accessible, cost-effective, and sustainable approach to augmenting daily physical activity levels. This study protocol endeavors to assess the impact of an active transportation education program rooted in the ecological model on the physical and mental well-being of high school students. Drawing upon scientific insights, we hypothesize that a 16-week active transportation intervention will lead to a 3% reduction in average body fat percentage and a noteworthy enhancement in executive function (including inhibition, cognitive flexibility, and working memory), physical fitness (comprising cardiorespiratory fitness and muscle strength), and mental health (encompassing mood disorders and cognitive functioning). If this intervention proves effective, it could offer a viable solution for the school community, especially in reducing congestion within the school environment. The study protocol aims to evaluate the impact of an active transportation educational program based on the ecological model on the physical and mental well-being of high school students. Three high schools located in the urban area of Talca, Chile, will be randomly selected (one public, one privately subsidized, and one private non-subsidized). Each high school will be randomly assigned an experimental group (n = 30) and a control group (n = 30; without intervention). The experimental groups will receive an active transportation educational intervention during their physical education classes for four months (60 to 90 min sessions, once a week), while the control group will receive no intervention. The primary outcome will provide information on body composition and executive function. Secondary outcomes will include objective physical activity level, physical fitness, mental well-being, academic achievement, health-related quality of life, perception of environmental urban features, physical activity barriers, and adherence to active transportation. It is expected that the results of the MOV-ES Project will transcend the physical health of schoolchildren and will have an impact on the school community, especially by decongesting the school environment.

Comparison between Measured and Predicted Resting Metabolic Rate Equations in Cross-Training Practitioners.

This study aimed to investigate the resting metabolic rate (RMR) in cross-training practitioners (advanced and novice) using indirect calorimetry (IC) and compare it with predictive equations proposed in the scientific literature. METHODS: A cross-sectional and comparative study analyzed 65 volunteers, both sexes, practicing cross-training (CT). Anthropometry and body composition were assessed, and RMR was measured by IC (FitMate PRO®), bioimpedance (BIA-InBody 570®), and six predictive equations. Data normality was tested by the Kolgomorov-Smirnov test and expressed as mean ± standard deviation with 95% confidence intervals (CI), chi-square test was performed to verify ergogenic resources, and a Bland-Altman plot (B&A) was made to quantify the agreement between two quantitative measurements. One-way ANOVA was applied to body composition parameters, two-way ANOVA with Bonferroni post hoc was used to compare the RMR between groups, and two-way ANCOVA was used to analyze the adjusted RMR for body and skeletal muscle mass. The effect size was determined using Cohen's d considering the values adjusted by ANCOVA. If a statistical difference was found, post hoc Bonferroni was applied. The significance level was p < 0.05 for all tests. RESULTS: The main results indicated that men showed a higher RMR than women, and the most discrepant equations were Cunningham, Tinsley (b), and Johnstone compared to IC. Tinsley's (a) equation indicated greater precision in measuring the RMR in CM overestimated it by only 1.9%, and BIA and the Harris-Benedict in CW overestimated RMR by only 0.1% and 3.4%, respectively. CONCLUSIONS: The BIA and Harris-Benedict equation could be used reliably to measure the RMR of females, while Tinsley (a) is the most reliable method to measure the RMR of males when measuring with IC is unavailable. By knowing which RMR equations are closest to the gold standard, these professionals can prescribe a more assertive diet, training, or ergogenic resources. An assertive prescription increases performance and can reduce possible deleterious effects, maximizing physical sports performance.

Narrative review: The role of circadian rhythm on sports performance, hormonal regulation, immune system function, and injury prevention in athletes.

Objectives: This study was a narrative review of the importance of circadian rhythm (CR), describes the underlying mechanisms of CR in sports performance, emphasizes the reciprocal link between CR, endocrine homeostasis and sex differences, and the unique role of the circadian clock in immune system function and coordination. Method: As a narrative review study, a comprehensive search was conducted in PubMed, Scopus, and Web of Science (core collection) databases using the keywords "circadian rhythm", "sports performance", "hormonal regulation", "immune system", and "injury prevention". Inclusion criteria were studies published in English and peer-reviewed journals until July 2023. Studies that examined the role of CR in sports performance, hormonal status, immune system function, and injury prevention in athletes were selected for review. Results: CR is followed by almost all physiological and biochemical activities in the human body. In humans, the superchiasmatic nucleus controls many daily biorhythms under solar time, including the sleep-wake cycle. A body of literature indicates that the peak performance of essential indicators of sports performance is primarily in the afternoon hours, and the evening of actions occurs roughly at the peak of core body temperature. Recent studies have demonstrated that the time of day that exercise is performed affects the achievement of good physical performance. This review also shows various biomarkers of cellular damage in weariness and the underlying mechanisms of diurnal fluctuations. According to the clock, CR can be synchronized with photonic and non-photonic stimuli (i.e., temperature, physical activity, and food intake), and feeding patterns and diet changes can affect CR and redox markers. It also emphasizes the reciprocal links between CR and endocrine homeostasis, the specific role of the circadian clock in coordinating immune system function, and the relationship between circadian clocks and sex differences. Conclusion: The interaction between insufficient sleep and time of day on performance has been established in this study because it is crucial to balance training, recovery, and sleep duration to attain optimal sports performance.

The Mediating Role of the Muscle Quality Index in the Relation of Screen Time and Abdominal Obesity with Health-Related Quality of Life in Chilean Schoolchildren.

Screen time (ST) and abdominal obesity have a negative effect on health-related quality of life (HRQoL). However, there is little information regarding the mediating role of the muscle quality index (MQI) in these relationships. The aim of the present study was to investigate the association between HRQoL, physical status (i.e., anthropometrics and fitness), lifestyle (i.e., ST and physical activity), and the MQI, and then to determine the potential mediating role of the MQI in the relation of ST and abdominal obesity with HRQoL in Chilean schoolchildren. The cross-sectional study included 750 schoolchildren (girls, n = 332 and boys, n = 418) aged between 10 and 14 years (11.73 ± 1.08 y). MQI, lifestyle, fitness parameters, waist-to-height ratio (WtHR) and HRQoL were measured. HRQoL presented a significant correlation with WtHR (r: -0.19), VO2max (r: 0.20), physical activity after school (r: 0.26), ST (r: -0.26) and MQI (r: 0.15). According to MQI, the high-MQI group reported higher HRQoL than the low-MQI group (low MQI: 36.10 ± 3.63 vs. high MQI: 37.43 ± 4.00, p < 0.001). In the mediation model, ST and abdominal obesity were negatively linked to HRQoL; the indirect effect confirmed that MQI is a partial mediator in the relation between ST and HRQoL (indirect effect = -0.04; SE = 0.02; 95% CI: -0.09, -0.01) and in the relation between abdominal obesity and HRQoL (indirect effect = -1.81; SE = 0.83; 95% CI: -3.41, -0.40). In conclusion, MQI is related to better HRQoL in schoolchildren, and the negative relation of ST and abdominal obesity with HRQoL is mediated by MQI.