Physiological stress of basketball referees during a national competition

abstract The aim of this study was to examine the physiological demands of seven referees during a national basketball competition. We recorded heart rate (HR), relative exercise intensity as a percentage of age – predicted maximum HR (HRmax), proportion of playing time within the exercise intensity categories defined by the ACSM during each of the tournament matches for each referee per period, as well as the entire game. None of the variables shows significant differences between periods. Based on a format of three referees per match, referees worked with an average HR of 150 bpm (range 110-181 bpm) for each quarter of the match, which equals a relative intensity> 70% of HRmax for most (∼76%) of each quarter. Other studies will assist in developing appropriate training programs for elite basketball referees to maintain and / or maximize performance.

Prevalence of overweight and obesity in Brazilian children and adolescents: a systematic review

abstract It is important to know about overweight and obesity situation of Brazilian children and adolescents. The present study aims to update scientific production, through a systematic review, on the prevalence and factors associated with overweight and obesity in Brazilian children and adolescents. Nine databases were verified, and 1,316 references were examined from 2018 to 2019. The electronic search was conducted by three independent researchers. All review steps followed a strategy based on PRISMA. 40 studies were included in this systematic review. Most studies use the World Health Organization classification criteria. The prevalence of overweight in Brazilian children and adolescents varies from 8.8% to 22.2% (boys: 6.2% to 21%; girls: 6.9% to 27.6%). The prevalence of obesity varied from 3.8% to 24% (boys: 2.4% to 28.9%; girls: 1.6% to 19.4%). It was observed that the socioeconomic factors (sex, skin color, economic level, region, mother's educational level, living in a rented house and without access to the internet), hereditary/genetic (family history of dyslipidemia and overweight and rs9939609 genotype) and behavioral (physical activity, screen time, eating habits, perceived body weight, health vulnerability, presence of a result close to home, alcoholic beverages, cigarette consumption) were associated with the outcome. It is concluded that the prevalence of overweight and obesity among Brazilian children and adolescents are worrisome and most of the factors associated with the outcomes are subject to change from the adoption of a healthy lifestyle.

Prevalence and correlates of excess body weight in university students

abstract – This study aimed to identify the prevalence of excess body weight in university students from a representative state in Brazil's southern region and establish associations with the demographic, university environment, and health behavior correlates. A random sample of 5,310 university students answered an online questionnaire with demographic, university environment, and eight health behavior data. Excess body weight was identified using the body mass index (BMI ≥ 25 kg/m2). The data were processed using bivariate analysis and hierarchical multiple regression. The overall prevalence of excess body weight exposure was equivalent to 39.1% [35.7-42.6], with significantly different rates between gender, age, and marital status. Likewise, housing type and study year showed significant associations with excess body weight. Among health behavior indicators, with control of all other variables involved in the model, depressive symptoms (p = 0.031), high stress (p = 0.045), sleep duration < 6 hours/night (p < 0.001), moderate-vigorous physical activity < 150 min/week (p = 0.022) and fruit/vegetable consumption < 5 servings per day (p < 0.001) were independently associated with the outcome. However, tobacco use, binge drinking, and prescription drug misuse did not remain in the adjusted multivariate model. In conclusion, the findings emphasize the importance of proposing and implementing multifaceted preventive intervention actions to prevent health outcomes related to excess body weight, once since significant associations with modifiable factors have been identified.

Relationship between postural changes and physical and functional variables in schoolchildren aged 6-12 years

The aim of this study was to evaluate the prevalence of postural changes and their relationship with BMI, pain, postures adopted in activities of the daily living (ADL), physical activity practice, gender and age (6 to 12 years). This study is characterized as cross-sectional, quantitative and descriptive. The convenience sample consisted of 840 schoolchildren. Regarding the sample characteristics, 477 (56.79%) were female aged 6-12 years (average=8.90±1.71years). Evaluations were carried out at the school premises and a questionnaire was used to collect data on gender, age, pain report, practice of out-of-school physical activities and postures adopted in ADLs. Body mass, height and posture were evaluated. Some schoolchildren (43.21%) reported not practicing physical activity outside of school, 544 (64.76%) correctly carried their backpack and 51.9% adopted correct postures to study and watch TV. Musculoskeletal pain was reported by 62.73%, and shoulders were the most affected. BMI indicated 55.6% of the sample with leanness/normal weight and 44.40% with overweight/obesity. Postural changes were present in 97.02% of students and the region with the highest number of alterations was the upper limbs. Girls presented greater number of trunk alterations (p=0.001), as well as those who did not practice physical activity (p=0.02) and alterations in the lower limbs for younger students (p=0.02) and female students (p=0.01). This study identified high prevalence of postural changes in schoolchildren.

Variations of workload and well-being measures across a professional basketball season

The aims of this study were: (i) to describe weekly variations of acute load (AL), acute:chronic workload ratio, delayed onset muscle soreness (DOMS), and fatigue; (ii) to analyze variations of weekly workload and well-being in three periods of the season (P1, P2, and P3); and (iii) to analyze the relationships between workload and well-being measures. Fifteen professional basketball players from a first-league European club were monitored throughout the season using the CR-10 Borg scale and the Hooper questionnaire. Weekly AL and acute:chronic workload ratio (ACWR) were weekly calculated for monitoring of the internal load. In addition, DOMS and fatigue values were weekly calculated. Greater AL, DOMS, and fatigue values were found during the early season, and the highest ACWR value was found during the second period. Overall, AL presented large correlations with DOMS (r=0.60) and fatigue (r=0.62). The results of this study indicate that load is higher in the first period and then decreases throughout the season. The results also showed that AL is more closely related to well-being parameters than ACWR.

Interval training during concurrent training optimizes cardiorespiratory adaptations in women

This study compared the effects of using continuous and interval aerobic exercise during concurrent training on cardiorespiratory adaptations in women. Thirty-two participants were randomly assigned into one of the following groups: continuous running and resistance training (C-RUN, n = 10), interval running and resistance training (I-RUN, n = 11), or control group that performed resistance training only (RT, n = 11). Each group trained twice a week during 11 weeks. Oxygen uptake corresponding to the first ventilatory threshold (VO2VT1), second ventilatory threshold (VO2VT2) and maximal effort (VO2max) was measured in a maximal incremental test performed before and after training. Significant increases in VO2VT1, VO2VT2 and VO2max were observed in all training groups. VO2VT2 and VO2max presented time-group interactions, indicating that the magnitude of the increase in these variables was dependent on the training group (VO2VT2: C-Run = 6.6%, I-Run = 15.7%, RT = 1.7%; VO2max: C-Run = 7.2%, I-Run = 14.3%, RT = 2.7%). The effect size observed for post-training values comparing C-RUN and RT groups was d = 0.566 for VO2VT2 and d = 0.442 for VO2max. On the other hand, values of d = 0.949 for VO2VT2 and d = 1.189 for VO2max were verified between I-RUN and RT groups. In conclusion, the use of continuous and interval aerobic exercise during concurrent training improved different cardiorespiratory parameters in women, but in a greater magnitude when interval aerobic exercise was performed simultaneously to resistance training.

Functional flexibility in institutionalized sedentary older adults

The aging process leads to deterioration in physiological functions, decreasing functional capacity. Since physical exercise reduces deleterious effects, measuring physical condition is necessary in older adults. The aim of this study was to verify the evolution of the range of motion in institutionalized sedentary older adults. The sample consisted of 19 volunteers aged 65-95 years who completed the Chair Sit-and-Reach test (CSR) and the Back-Scratch test (BS) to measure flexibility of the lower and upper limbs, respectively, before and after a period of 12 weeks without intervention. The results showed significant decrease during the control period (BS, p=0.004; CSR, p=0.001). These findings confirm that physical inactivity could lead to important loss of flexibility of institutionalized individuals, indicating decline of the elastic properties of musculoskeletal tissues and of connective tissues of joints. Therefore, the participation of institutionalized older adults in properly prescribed and guided physical exercises should be continuous and regular.

Obesity and decrease of daily physical activity among children and adolescents: a follow-up study

ABSTRACT We analyzed the effect of obesity on daily physical activity (DPA), light-intensity physical activity (LPA), moderate-intensity physical activity (MPA) and vigorous- intensity physical activity (VPA) in children and adolescents. Overall, 462 students from a public school (53.6% boys; aged 7-12 years) were involved in this one-year longitudinal study. Physical activities and sedentary behaviors (SB) were reported in the questionnaire Food Intake and Physical Activity of Students (Web-CAAFE). Obesity was evaluated through Body Mass Index (BMI z score ≥ 2). Obesity was observed in 16.5% of participants, but it did not influence LPA, MPA or DPA. However, VPA were 20% less frequent among obese students (β2=0.80; CI 95%: 0.66-0.98). Obese girls showed less frequency of VPA than non-obese boys (Mean Difference = -0.97; CI 95%: -1.36 to -0.57). Non-obese girls showed less VPA than non-obese boys (Mean Difference = -1.18; CI 95%: -1.40 to -0.95) and obese ones (Mean Difference = -0.57; CI 95%: -0.90 to -0.24). Obese boys showed fewer VPA, if compared to non-obese ones (Mean Difference = -0.61; CI 95%: -0.96 to -0.26). The analysis of the obesity-sex-age interaction showed a greater reduction in VPA among obese girls aged 10 years or more when compared to obese girls aged 7-9 years, and among boys obese and non-obese regardless of age. Amounts of VPA and SB increased simultaneously among non-obese boys and non-obese children aged 7-9 years. Obesity reduced VPA in the sample during the follow up of one year, independently of age and SB.

The influence of the ACTN3 R577X polymorphism in the responsiveness to post-activation jump performance enhancement in untrained young men

ABSTRACT We aimed to investigate the influence of alpha-actinin-3 (ACTN3) R577X polymorphism on responsiveness to post-activation performance enhancement (PAPE) of countermovement jumps (CMJ) in untrained subjects. Sixteen untrained men were allocated into two groups according to their ACTN3 gene alleles: homozygous for the X allele (XX, n = 9) or homozygous for the R allele (RR, n = 7). CMJ height, mean power output and vertical force were determined twice (CMJ1 and CMJ2) in two conditions: control (CON) and potentiated (PAPE). In the CON condition, CMJ were performed before and after a 15-min rest. In the PAPE condition, CMJ were performed 15 min before and 4 min following five squats with a 5-repetition maximum (5RM) load. Different conditions were applied on separate days in a randomized order. Statistical analysis involved three-way ANOVAs to compare the differences between conditions (CON and PAPE), time (CMJ1 and CMJ2), and groups (XX and RR). Significance level considered was p < 0.05. Effect sizes were calculated as Cohen’s d. The effect sizes for changes in CMJ height for CON and following pre-activation for PAPE were 0.04 and 0.08, respectively. No significant differences were found for CMJ height between XX and RR at baseline (1.07 ± 2.54 cm e -0.82 ± 2.56 cm, respectively). No differences were found (p>0.05) in responsiveness to PAPE between the groups (XX = -0.20 ± 1.6 cm and RR = -0.81 ± 2.7 cm). We conclude that ACTN3 gene polymorphisms does not influence responsiveness to PAPE.

Analysis of serve and serve return on different surfaces in elite tennis players

The aim of the current study was to analyze players’ interactions in serve and serve return situations and examine the way points were decided due to players’ positions and surfaces. Fourteen ATP 1000 tournament matches were analyzed (7 on hard surface; 7 on clay surface). The type of surface did not affect the way points ended (χ²=9.26; p > 0.05) but did influence serve return vertical positioning (χ²=270.86; p < 0.001). The return positioning, both lateral (χ²=92.68; p < 0.001 on deuce side - χ² = 78.98; p < 0.001 on advantage side) and vertical (χ²=33.59; p < 0.001), and the type of serve (χ²=45.13; p < 0.001) affected the way points were decided. The results from the present study suggest that tennis players should use, or at least seek, strategies based on aggressiveness and consistency of the 1st serve and also indicate that in the 2nd serve return, players are more offensive, and that on hard surfaces, players stand a few steps inside the court to return the serve, differently from clay surfaces. It recommended that serve returns should combine aggression, by inside the court positioning, and accuracy.