Factors associated with perceived performance drops and musculoskeletal injuries in Brazilian recreational triathletes.

OBJECTIVE: The aim of the study was to investigate sleep characteristics, use of supplements, and training volume of recreational triathletes, and to verify possible associations with perceived performance drops and occurrence of injuries. MATERIALS AND METHODS: Recreational triathletes (n=942) answered a questionnaire inquiring about their demographic characteristics, performance, injuries and training volume. RESULTS: When comparing athletes who slept more (9-10 hours) with those who slept less, less sleep was associated with a higher prevalence of perceived performance drops. Regarding difficulties in initiating sleep, the absence of initiating difficulties (p<0.001) was a protective factor against perceived performance drops. Regarding weekly training volume, compared to those who trained more than 20 hours, training less than 3 hours (p<0.001), 3-5 hours (p<0.001), or 12-14 hours (p<0.001) were protective factors against perceived performance drops. Concerning training volume and injuries, we found that compared to those who trained more than 20 hours, training 18-20 hours (p<0.001), 15-17 hours (p<0.001), 12-14 hours (p<0.001), 6-8 hours (p<0.001), or 3-5 hours (p<0.001) were protective factors against injuries. CONCLUSIONS: Triathletes with a lower sleep quantity and those who have difficulties initiating sleep frequently experience drops in performance. Training volumes can influence both performance and the likelihood of injuries.

Effects of aerobic and strength training on depression, anxiety, and health self-perception levels during the COVID-19 pandemic.

OBJECTIVE: This study aimed at comparing the depression and anxiety levels, and health self-perception during the coronavirus disease 2019 pandemic among subjects who practice aerobic, strength, and mixed (aerobic and strength) exercises and nonsports participants. MATERIALS AND METHODS: We included 304 Brazilians of both sexes in this cross-sectional study. All participants were recruited through online advertisement and completed a self-administered questionnaire regarding the personal information, level of restriction adopted, physical activity, and mood state screening (Patient Health Questionnaire-9 and General Anxiety Disorder-7). We divided the participants into four groups: strength sports group (CrossFit or strength training), aerobic/endurance sports groups (running, cycling, triathlon, or swimming), mixed sports groups (individuals who practice endurance and strength sports), and nonsports group. RESULTS: The Kruskal-Wallis test showed a significant effect of the group on the depression and anxiety levels. Meanwhile, the post-hoc comparisons showed a significantly lower depression level in the mixed and aerobic sports groups than in the strength sports and nonsports groups, and a significantly lower anxiety level in the mixed and aerobic sports groups than in the nonsports group. Furthermore, participants in the mixed, strength, and aerobic sports groups presented a better level of health self-assessment than the nonsports group, and those in the mixed sports group had a better level of health self-assessment than the strength or aerobic sports groups. CONCLUSIONS: Individuals practicing aerobic exercises present lower depression and anxiety levels than those practicing strength training and are inactive. However, individuals who practice strength exercises and aerobics have the best levels of health perception.

Comparison of the levels of depression and anxiety during the first and fourth waves of coronavirus disease-2019 pandemic in Brazil.

OBJECTIVE: To compare the levels of depression, anxiety, physical activity, and mobility restrictions between the first wave in June 2020 and the fourth wave in January 2022 of the coronavirus disease-2019 (COVID-19) pandemic in Brazil. PATIENTS AND METHODS: Brazilian citizens answered a self-administered questionnaire that included questions related to personal information, mobility restriction levels, physical activity levels, and the status of mood disorders in June 2020 (n=1853) and January 2022 (n=728). RESULTS: The levels of mobility restrictions (p<0.001), anxiety (p<0.001), and depression (p<0.001) significantly decreased from 2020 to 2022. In June 2020, 23.2% of the participants presented moderate to severe anxiety, and in January 2022, this percentage decreased to 14.8%. In June 2020, 29.6% of the participants presented moderate to severe depressive symptoms, and in January 2022 this percentage decreased to 19.3%. On the contrary, physical activity levels significantly increased between 2020 and 2022 (p<0.001). CONCLUSIONS: During the fourth wave of the COVID-19 pandemic, participants were less restricted and more physically active than in the first wave. Furthermore, anxiety and depression levels were significantly lower in the fourth wave than in the first wave. Despite this reduction, levels of anxiety and depression remain high; therefore, the authors suggest measures to encourage physical activity and promote mental health.

The aspects of sex, age and nationality in winter swimming performance.

OBJECTIVE: Winter swimming is a new sport discipline. Very little is known, however, about the sex differences, origin, participation and performance of the world's best winter swimmers. Therefore, the study aimed to investigate sex differences in performance and age. Furthermore, it should be determined which country has the fastest swimmers, the highest numbers of participants and the most successful age group athletes in winter swimming. SUBJECTS AND METHODS: A total of 6,477 results from the 25 m events of the IWSA (International Winter Swimming Association) World Cups from 2016-2020 was collected from the official website of IWSA. Data were analyzed using a generalized linear model (GLM) with a gamma probability distribution and identity link function. The 25 m events were carried out in head-up breaststroke style, freestyle and butterfly. The nationalities were grouped into six groups, the five nationalities with the highest number of participants in the 25 m competitions and one group with the other nationalities. The mean time of 25 m races by sex and country of the total sample was compared. For the top 10 comparisons, the best ten athletes from the six groups were selected. The mean time of each top 10 groups was compared by sex and nationality. RESULTS: Men were faster than women for all categories. Swimmers in age group 15-29 years were the fastest, where females were the fastest in age group 15-19 years and males in age group 20-29 years. Women from both Russia and Estonia and men from both Russia and China were the fastest. Both Russian and Chinese males were the fastest in all water categories in the top 10 section in the 25 m events. CONCLUSIONS: In summary, males were faster than females in the IWSA World Cups between 2016 and 2020. The age group of 15-29 years old athletes was the most successful while females had their age of peak performance earlier than males. Russian and Estonian males and Russian females were the overall fastest in the 25 m events in all water categories. Future studies should investigate the optimal anthropometric characteristics of male and female winter swimming sprint athletes and whether there are distinct areas in Russia, Estonia and China, where many international winter swimming athletes originate.

Association between lowering restriction levels during the coronavirus outbreak and physical activity among adults: a longitudinal observational study in Brazil.

OBJECTIVE: The COVID-19 pandemic has had significant consequences on public health and lifestyle and has negatively affected mental health and the level of physical activity worldwide. This study examined the impact of reopening fitness centers and nonessential services and introducing flexible measures to ensure social distancing on physical activity and mental health. MATERIALS AND METHODS: This was a longitudinal study. A self-administered questionnaire, including personal, behavioral, physical activity, perception of health, and mood state disorder information, was answered by 128 Brazilians in June 2020 (during severe restrictive measures) and again in April 2021 (after fitness centers and nonessential services were reopened). RESULTS: The restriction level adopted in April 2021 was significantly lower than that in June 2020 (p<0.001). The level of physical activity (p<0.001) and health status perception (p<0.001) decreased from June 2020 to April 2021. The median values for depression and anxiety did not differ across the study period. CONCLUSIONS: The level of physical activity was reduced during the COVID-19 pandemic, and anxiety and depression were not improved following less restrictive social distancing measures and the reopening of fitness centers. Thus, the return to a prepandemic level of physical activity and mental health status may not be automatic. The results presented herein suggest that the decrease in physical activity observed in the population may be challenging in the postpandemic period.

Strength field tests performance are correlated with isokinetic strength of shoulder rotator muscles in female handball players.

BACKGROUND: The aim of this study was to analyze the relationship between the isokinetic shoulder strength of the athletes and their performance on strength field tests. Data on the balance and functional strength ratios of the internal and external rotator muscles of shoulders of handball players was also investigated. METHODS: Twenty-seven female athletes (23±3.4 years, 71±10.6 kg and 173.3±7.1 cm) underwent an isokinetic assessment of the strength of the shoulder rotator muscles. Athletes also performed the following strength field tests: bench press test, lying bench barbell row test, handgrip test, and medicine ball throwing. RESULTS: The bench press test results and the lying bench barbell row test results were significantly correlated with the concentric internal and external rotator peak torques at 1.05 rad.s-1 and 5.23 rad.s-1, with total work at 1.05 rad.s-1 and with average power at 5.23 rad.s-1 (r=0.51 to 0.81). CONCLUSION: We suggested the use of field test to infer about internal and external rotator muscular strength, but not to infer about isokinetic muscular strength ratios. These findings could be useful to coaches and trainers.

Analytical linear theory for the interaction of a planar shock wave with a two- or three-dimensional random isotropic density field.

We present an analytical linear model describing the interaction of a planar shock wave with an isotropic random pattern of density nonuniformities. This kind of interaction is important in inertial confinement fusion where shocks travel into weakly inhomogeneous cryogenic deuterium-wicked foams, and also in astrophysics, where shocks interact with interstellar density clumps. The model presented here is based on the exact theory of space and time evolution of the perturbed quantities generated by a corrugated shock wave traveling into a small-amplitude single-mode density field. Corresponding averages in both two and three dimensions are obtained as closed analytical expressions for the turbulent kinetic energy, acoustic energy flux, density amplification, and vorticity generation downstream. They are given as explicit functions of the two parameters (adiabatic exponent γ and shock strength M(1)) that govern the dynamics of the problem. In addition, these explicit formulas are simplified in the important asymptotic limits of weak and strong shocks and highly compressible fluids.

Relationship between aerobic and anaerobic parameters and functional classification in wheelchair basketball players.

Participation in sports for individuals with disabilities continues to gain popularity. In order to provide fair and equitable competition among persons with different disabilities and functional capacity, a separate functional classification system has been devised for each sport. The aims of the present study were to evaluate aerobic and anaerobic performance of wheelchair basketball athletes and verify a correlation with the International Wheelchair Basketball Federation functional classification system. For this, 17 highly trained male Brazilian basketball wheelchair athletes (25.4+/-4.4 years) from the national team who had taken part in the Athens 2004 Paralympic Games were assessed. These athletes were submitted to cardiopulmonary exercise testing and Wingate-like 30-s sprint test using upper limbs. The present study demonstrated that the functional classification score correlated with relative (r=0.90; P<0.0001) and absolute peak power (r=0.50; P=0.0353) and absolute mean power (r=0.93; P<0.0001) obtained from the Wingate-like 30-s sprint test and also correlated with absolute O(2) peak (r=0.68; P=0.0026) and O(2) at ventilatory threshold (r=0.71; P=0.0014), measured on cardiopulmonary exercise testing. Therefore, our findings support the functional classification created to classify athletes' functional capability on the court, which also correlated with aerobic and anaerobic performance parameters of the elite wheelchair basketball players.

Analytical linear theory for the interaction of a planar shock wave with an isotropic turbulent vorticity field.

An exact analytical model for the interaction between an isolated shock wave and an isotropic turbulent vorticity field is presented. The interaction with a single-mode two-dimensional (2D) divergence-free vorticity field is analyzed in detail, giving the time and space evolutions of the perturbed quantities downstream. The results are generalized to study the interaction of a planar shock wave with an isotropic three-dimensional (3D) or 2D preshock vorticity field. This field is decomposed into Fourier modes, and each mode is assumed to interact independently with the shock front. Averages of the downstream quantities are made by integrating over the angles that define the orientation of the upstream velocity field. The ratio of downstream/upstream kinetic energies is in good agreement with existing numerical and experimental results for both 3D and 2D preshock vorticity fields. The generation of sound and the sonic energy flux radiated downstream from the shock front is also discussed in detail, as well as the amplification of transverse vorticity across the shock front. The anisotropy is calculated for the far downstream fields of both velocity and vorticity. All the quantities characteristic of the shock-turbulence interaction are reduced to closed-form exact analytical expressions. They are presented as explicit functions of the two parameters that govern the dynamics of the interaction: the adiabatic exponent gamma and the shock Mach number M1 . These formulas are further reduced to simpler exact asymptotic expressions in the limits of weak and strong shock waves (M_{1}-11, M_{1}1) and high shock compressibility of the gas (gamma-->1) .

Physicochemical characterization of nopal pads (Opuntia ficus indica) and dry vacuum nopal powders as a function of the maturation.

This paper presents the physicochemical and nutrimental characterization of fresh nopal (Opuntia ficus indica, Redonda variety) and nopal powder produced at different stages of development. Nopal powder was obtained by dry vacuum technique using 10(2) Torr and low temperature (40 degrees C). The results showed that the nutrimental and mineral composition of nopal changes as a function of the maturation as follow: The ash content increases from 18.41 for nopalitos (60 g of weight) to 23.24% (nopal pads 200 g); calcium content increases from 1.52 to 3.72%, while phosphorous exhibits an opposite trend: 0.43 to 0.27%, respectively. Calcium oxalate was determined by X-ray diffraction and SEM microscopy and quantified by using atomic absorption spectroscopy. Calcium oxalate decreases from 7.95 to 3.47 mg/g and the Ca/P ratio varies from 3.6 to 11. The soluble fibre decreases from 25.22 to 14.91%, while insoluble fibre increases from 29.87 to 41.65%. These results suggest that nopal could be an important source of minerals within the diets of people in Mexico and the rest of Latin America.