Interval Training with Different Intensities in Overweight/Obese Adolescent Females.

To compare the effects of 12 weeks of high-intensity interval training (HIIT) versus moderate-intensity interval training (MIIT) on hematological and inflammatory markers in youth females, 38 overweight/obese females (16.4±1.0 yrs.) were randomly assigned to HIIT (2×6-8 repetitions of 30 s at 100-110% maximal aerobic speed (MAS), with 30 s active recovery between repetitions at 50% MAS; n=13), MIIT (2×6-8 repetitions of 30 s at 70-80% MAS, with 30 s active recovery between repetitions at 50% MAS; n=13), and a control group (CG, no intervention; n=12). Body composition, blood pressure, maximal heart rate, hematological and inflammatory markers (C-reactive protein [CRP], and erythrocyte sedimentation rate [ESR]) markers were assessed in all groups before and following the training program. Results revealed a significant (P<0.05) interaction effect for body composition, systolic blood pressure (SBP), MAS, maximal heart rate, and CRP. Within-group analyses for the HIIT and MIIT groups showed significant improvements in body mass (P=0.009 and P=0.025, respectively), BMI Z-score (P=0.011 and P=0.028, respectively), and MAS (P<0.001 and P=0.011, respectively). The HIIT program showed a significant decrease in body fat (P=0.002), waist circumference (P=0.002), maximal heart rate (P=0.003), SBP (P=0.001), and plasma CRP (P=0.004). In both groups, no significant changes were observed in ESR and hematological markers after intervention. No variable changed in CG. HIIT was the effective method to manage cardiometabolic health and inflammatory disorders in obese youth.

Isokinetic Muscular Strength and Aerobic Physical Fitness in Recreational Long-Distance Runners: A Cross-Sectional Study.

ABSTRACT: Andrade, MS, Silva, WA, de Lira, CAB, Mascarin, NC, Vancini, RL, Nikolaidis, PT, and Knechtle, B. Isokinetic muscular strength and aerobic physical fitness in recreational long-distance runners: A cross-sectional study. J Strength Cond Res 36(3): e73-e80, 2022-Muscular strength, bilateral asymmetry, and imbalance between antagonist muscles have been considered as risk factors for knee injuries. Moreover, muscular strength has also been associated with aerobic performance. The aim of the study was to investigate bilateral muscular symmetry and muscular strength balance assessed by isokinetic dynamometry in recreational long-distance runners and to verify whether knee muscular strength would be associated with maximal oxygen uptake (V̇o2max), anaerobic threshold (AT), and running economy (RE). Thirty-nine runners (male [n = 24]: age, 30 ± 8 years; height, 176.0 ± 7.3 cm; body mass, 70.3 ± 8.0 kg; race pace below 4:30 min·km-1 and female [n = 15]: age, 31 ± 7 years; height, 163.0 ± 3.8 cm; body mass, 55.9 ± 4.7 kg; race pace below 5:00 min·km-1) participated in this study. Comparing the conventional knee balance ratio with the literature recommendation (60%), male runners presented significantly lower values for the nondominant side (55.5 ± 7.3%; p = 0.001; d = 0.85; confidence interval [CI] = 0.47 to 1.20) but not for the dominant side (58.1 ± 6.8%; p = 0.208; d = 0.37; CI = -0.12 to 0.86). Female runners presented lower values for both sides (52.1 ± 7.1%; p = 0.001; d = 1.55; CI = 0.86 to 2.20 and 50.7 ± 8.0%; p = 0.001; d = 1.62; CI = 0.90 to 2.30 for dominant and nondominant sides, respectively). Female and male runners presented nonfunctional ratio imbalance and asymmetry of bilateral strength. Strength outcomes were not associated with V̇o2max, AT, or RE. In conclusion, recreational runners were characterized by an imbalance in muscular strength between knee flexor and extensor muscles, which was more obvious in female runners, and by symmetrical thigh muscle strength values. Moreover, muscular isokinetic knee flexor and extensor muscle strength was not associated with aerobic fitness parameters.

Return to classes impact on mental health of university students during the COVID-19 pandemic.

BACKGROUND: The coronavirus disease 2019 (COVID-19) pandemic and the necessary social isolation and distancing measures - that were adopted to prevent spreading the virus, including the suspension of university classes - negatively impacted the mental health of young adults. The aim of the current study was to investigate whether returning to online classes, even not presential, during the social isolation of the COVID-19 pandemic, affected the mental health of university students. METHODS: Forty students (10 men and 30 women) (age, 22.3 ± 3.8 years; body mass, 62.5 ± 17.8 kg; height, 165.6 ± 8.7 cm) from undergraduate health courses participated in the study. The students answered a self-administered questionnaire designed to gather personal and quarantine information as well as information about the frequency of depression (PHQ-9) and anxiety (GAD-7) symptoms. The questionnaire was answered before and after the return to online classes. RESULTS: There was a significantly lower frequency of depression symptoms after the return to online classes (Z = -2.27; p = 0.02). However, there was no difference in anxiety symptoms before and after returning to online classes (Z = -0.51; p = 0.61). CONCLUSIONS: Return to online classes positively impacted the mental health (decrease of frequency of depression symptoms) of university students. Future studies are needed to observe whether the changes observed after returning to school are maintained over time.

Trends in Participation, Sex Differences and Age of Peak Performance in Time-Limited Ultramarathon Events: A Secular Analysis.

Background and Objectives: Increases in the number of participants in time-limited ultra-marathons have been reported. However, no information is available regarding the trends in participation, performance and age in 12 h and 24 h time-limited events. The aim of the study was to describe the trends in runners' participation, performance and age in 12 h and 24 h ultra-marathons for both sexes and to identify the age of peak performance, taking into account the ranking position and age categories. Materials and Methods: The sample comprised 210,455 runners in time-limited ultra-marathons (female 12 h = 23,706; female 24 h = 28,585; male 12 h = 61,594; male 24 h = 96,570) competing between 1876 and 2020 and aged 18 to 86 years. The age of peak performance was tested according to their ranking position (first−third; fourth−tenth and >tenth position) and taking into account their running speed in different age categories (<30 years; 31−40 years; 41−50 years; 51−60 years; >60 years), using the Kruskal−Wallis test, followed by the Bonferroni adjustment. Results: An increase in the number of participants and a decrease in running speed were observed across the years. For both events, the sex differences in performance decreased over time. The sex differences showed that male runners performed better than female runners, but the lowest differences in recent years were observed in the 24 h ultra-marathons. A positive trend in age across the years was found with an increase in mean age ("before 1989" = 40.33 ± 10.07 years; "1990−1999" = 44.16 ± 10.37 years; "2000−2009" = 45.99 ± 10.33 years; "2010−2020" = 45.62 ± 10.80 years). Male runners in 24 h races were the oldest (46.13 ± 10.83 years), while female runners in 12 h races were the youngest (43.46 ± 10.16 years). Athletes ranked first−third position were the youngest (female 12 h = 41.19 ± 8.87 years; female 24 h = 42.19 ± 8.50 years; male 12 h = 42.03 ± 9.40 years; male 24 h = 43.55 ± 9.03 years). When age categories were considered, the best performance was found for athletes aged between 41 and 50 years (female 12 h 6.48 ± 1.74 km/h; female 24 h 5.64 ± 1.68 km/h; male 12 h 7.19 ± 1.90 km/h; male 24 h 6.03 ± 1.78 km/h). Conclusion: A positive trend in participation in 12 h and 24 h ultra-marathons was shown across the years; however, athletes were becoming slower and older. The fastest athletes were the youngest ones, but when age intervals were considered, the age of peak performance was between 41 and 50 years.

The Sex Difference in 6-h Ultra-Marathon Running-The Worldwide Trends from 1982 to 2020.

Background and Objectives: The 6-h ultra-marathon is the shortest time-limited ultra-marathon race, but little has been investigated regarding this race format. Previously, only the age of peak performance in the context of longer time-limited ultra-marathons was determined. The purpose of this study was to investigate the trends in 6-h ultra-marathon races from 1982 to 2020 for female and male ultra-runners, the participation and performance by countries, the age of peak performance, and the differences in performance regarding countries. Materials and Methods: The sample included 23,203 female ultra-runners, aged 18-83 years, and 87,264 male ultra-runners, aged 18-85 years, who were finishers in a 6-h ultra-marathon held between 1982 and 2020. The age of peak performance was tested using the Kruskal-Wallis test, followed by the Bonferroni Correction. The difference in performance by countries was verified using a linear regression model with the fastest runners from Russia in women, and Tunisia in men, used as reference. Results: Over the years, the men-to-women ratio decreased. The mean age was 43.20 ± 9.30 years for female and 46.09 ± 10.17 years for male runners. Athletes in younger age groups were faster than athletes in older age groups. Most female and male participants originated from Germany. Women from Russia (10.01 ± 1.28 km/h) and men from Tunisia (12.16 ± 1.46 km/h) were the fastest. Conclusions: In summary, in 6-h ultra-marathons held between 1982 and 2020, the participation for both women and men increased, while the men-to-women ratio decreased. The mean age was higher in men compared to women. Most female and male runners originated from Germany, but the fastest women were from Russia, and the fastest men from Tunisia. Future studies need to investigate whether Russian women and Tunisian men are also the best in other distance-limited ultra-marathon races, such as 12-h and 24-h.

Training, psychometric status, biological markers and neuromuscular fatigue in soccer.

The study examined the relationship between psychometric status, neuromuscular, and biochemical markers of fatigue in response to an intensified training (IT) period in soccer. Fifteen professional soccer players volunteered to participate in the study (mean ± SD: age: 25 ± 1 years; body height: 179 ± 7 cm, body mass: 73.7 ± 16.2 kg, experience: 13.2 ± 3 years). Training load, monotony, strain, Hooper index and total quality recovery (TQR) were determined for each training session during a 2-week of IT. Counter-movement jump (CMJ) and biochemical responses [testosterone, cortisol, testosterone-to-cortisol ratio (T/C ratio), creatine kinase, and C-reactive protein] were collected before and after IT. Results showed that IT induced significant increases in cortisol, creatine kinase and C-reactive protein and significant decreases in T/C ratio and CMJ performance from before to after IT (p < 0.01, p < 0.001, p < 0.001, p < 0.01, p < 0.05, respectively). However, testosterone did not differ from before to after IT (p > 0.05). Training loads were positively correlated with Hooper index (p < 0.05) and negatively correlated with total quality recovery (p < 0.05). Hooper index was positively correlated with cortisol (p < 0.05), T/C ratio (p < 0.01), and creatine kinase (p < 0.01), and negatively correlated with CMJ (p < 0.05). Furthermore, TQR was negatively correlated with T/C ratio (p < 0.01), creatine kinase (p < 0.001), and C-reactive protein (p < 0.05), and positively correlated with CMJ (p < 0.01). Neuromuscular fatigue, muscle damage, and change in the anabolic/catabolic state induced by the IT were related to well-being and perceived recovery state among professional soccer players.

Body composition adaptations to lower-body plyometric training: a systematic review and meta-analysis.

The aim of this meta-analysis was to explore the effects of plyometric jump training (PJT) on body composition parameters among males. Relevant articles were searched in the electronic databases PubMed, MEDLINE, WOS, and SCOPUS, using the key words "ballistic", "complex", "explosive", "force-velocity", "plyometric", "stretch-shortening cycle", "jump", "training", and "body composition". We included randomized controlled trials (RCTs) that investigating the effects of PJT in healthy male's body composition (e.g., muscle mass; body fat), irrespective of age. From database searching 21 RCTs were included (separate experimental groups = 28; pooled number of participants = 594). Compared to control, PJT produced significant increases in total leg muscle volume (small ES = 0.55, p = 0.009), thigh muscle volume (small ES = 0.38, p = 0.043), thigh girth (large ES = 1.78, p = 0.011), calf girth (large ES = 1.89, p = 0.022), and muscle pennation angle (small ES = 0.53, p = 0.040). However, we did not find significant difference between PJT and control for muscle cross-sectional area, body fat, and skinfold thickness. Heterogeneity remained low-to-moderate for most analyses, and using the Egger's test publication bias was not found in any of the analyses (p = 0.300-0.900). No injuries were reported among the included studies. PJT seems to be an effective and safe mode of exercise for increasing leg muscle volume, thigh muscle volume, thigh and calf girth, and muscle pennation angle. Therefore, PJT may be effective to improve muscle size and architecture, with potential implications in several clinical and sport-related contexts.

Effects of strength training with elastic band programme on fitness components in young female handball players: a randomized controlled trial.

This study examined the effect of a 10-week programme of strength training with elastic band (STEB) on fitness components in young female handball players. Twenty-six young female handball players (aged 15.8 ± 0.2 years) from the same club participated in this study. They were randomly assigned between experimental (EG; n = 13) and control (CG; n = 13) groups. The EG performed the STEB, replacing some handball-specific drills in the regular handball training. The CG followed the regular handball training (i.e., mainly technical-tactical drills, small sided and simulated games, and injury prevention drills). Two-way analyses of variance were used to assess: handgrip; back extensor strength; medicine ball throw; 30 m sprint times; Modified Illinois change-of-direction (Illinois-MT); four jump tests: squat jump (SJ), countermovement jump (CMJ), countermovement jump with arm swing (CMJA) and five-jump test (5JT); static (Stork test) and dynamic balance (Y Balance Test); and repeated sprint T-test (RSTT). Results revealed significant gains in handgrip - right (p < 0.001, d = 1.75: large), handgrip - left (p < 0.001, d = 2.52: large), back extensor (p < 0.001, d = 2.01: large), and medicine ball throw (p = 0.002, d = 0.95: large) with EG compared to the CG. The EG also demonstrated greater improvement in sprint performance over 20 m (Δ = 10.6%, p = 0.001, d = 1.07: large) and 30 m (Δ = 7.2%, p < 0.0001, d = 1.56: large) compared to the CG. The EG showed better Illinois-MT (Δ = 5.6%, p = 0.034, d = 0.62: medium) compared to the CG. Further, EG posted significant improvements in the SJ (Δ = 17.3%, p = 0.048, d = 0.58: medium), CMJ (Δ = 17.7%, p = 0.017 d = 0.71: medium), and CMJA (Δ = 16.3%, p = 0.019, d = 0.69: medium) compared to the CG. Similarly, the EG exhibited significant improvement in RSTT best time [p = 0.025, d = 0.66 (medium)], RSTT mean time [p = 0.019, d = 0.69 (medium)] and RSTT total time [p = 0.019, d = 0.69 (medium)] compared to the CG. In conclusion, the 10-week STEB improved the physical abilities in young female handball players.

Fear of failure in Brazilian runners.

This study aims to investigate the fear or failure (FoF) in Brazilian runners of both sex, performance levels and age categories, as well as to verify the relationship between FoF and socioeconomic status (SES). Sample size as composed by 916. Age, sex, body height, body weight, SES, and running pace were self-reported. The Multidimensional Questionnaire of FoF was applied in an online platform. Running pace, and SES were categorized and processed through multivariate analysis and Spearman correlations, with the p-value set at 0.05. Female runners with better performance (2.13 ± 0.74) and younger (2.16 ± 0.80), as a well as male runners with worse performance (2.04 ± 0.69) and older (2.04 ± 0.89) presented the highest values of FoF. Among women, SES was negatively associated with FoF (r = -0.144; p = 0.006), while a positive association between running pace and SES was observed among men (r = 0.290; p < 0.001). Non-professional Brazilian runners presented low values of FoF.

Reduced level of physical activity during COVID-19 pandemic is associated with depression and anxiety levels: an internet-based survey.

BACKGROUND: The coronavirus disease 2019 (COVID-19) pandemic has resulted in a strong negative impact on economic and social life worldwide. It has also negatively influenced people's general health and quality of life. The aim of the present study was to study the impact of social distancing on physical activity level, and the association between mood state (depression and anxiety level) or sex with actual physical activity levels, the change in physical activity caused by social distancing period, the adhesion level to social distancing, the adoption time of social distancing, family income and age. METHODS: A self-administered questionnaire with personal, quarantine, physical activity, and mood state disorders information's was answered by 2140 Brazilians of both sex who were recruited through online advertising. RESULTS: The physical activity level adopted during the period of social distancing (3.5 ± 0.8) was lower than that the adopted prior to the pandemic period (2.9 ± 1.1, p < 0.001). Thirty percent of the participants presented symptoms of moderate/severe depression and 23.3% displayed moderate/severe anxiety symptoms. A greater presence of symptoms related to anxiety and depression were associated with low physical activity levels, low family monthly income, and younger age. A higher percentage of men who had no mood disorders was observed among those who were very active than among those less active. CONCLUSION: The COVID-19 pandemic has a negative impact on physical activity. Those who reduced their level of physical activity had the highest levels of mood disorders. Therefore, physical activity programs should be encouraged, while respecting the necessary social distancing to prevent the spread of Severe Acute Respiratory Syndrome Coronavirus 2.

Exergaming and Aquatic Exercises Affect Lung Function and Weight Loss in Obese Children.

We investigated the effect of exergames and aquatic exercises on lung function and weight loss in obese children. Sixty-one obese male primary-school children were randomly allocated to video game, aquatic exercise, and control groups. Lung functions and anthropometric variables were measured before and after the intervention and after one month (follow-up). In the video game group, an Xbox Kinect game was played for 60 min during three sessions a week. The aquatic aerobic exercise was performed three times per week and consisted of a warm-up, main exercises, and a cool down phase. For the video game group, there was a significant reduction in body weight between (i) pre- and (ii) post-intervention and follow-up. In the aquatic exercise group, there was a significant reduction in body weight between pre- and post-intervention and between pre-intervention and follow-up. Both exercise groups improved the waist/hip ratio index compared to the control group. Forced vital capacity was significantly improved in the follow-up of the video game group and the aquatic exercise group compared to the control group. A significant improvement was found in forced expiratory volume in the first second at post-intervention and follow-up in the video game and the aquatic exercise groups. Exergames and aquatic exercises improved weight loss and lung function in obese children.

Participation and Performance Trends in the ITU Duathlon World Championship From 2003 to 2017.

ABSTRACT: Nikolaidis, PT, Villiger, E, and Knechtle, B. Participation and performance trends in the ITU Duathlon World Championship from 2003 to 2017. J Strength Cond Res 35(4): 1127-1133, 2021-Participation and performance across years have been studied extensively in various endurance and ultra-endurance sports; however, less information exists with regards to duathlon (i.e., Run 1, Bike, and Run 2). The aim of this study was to examine performance and participation trends of duathletes competing either to short (10-km Run 1, 50-km Bike, and 5-km Run 2) or to long distance (10-km Run 1, 150-km Bike, and 30-km Run 2) in the Powerman World Championship "Powerman Zofingen." We analyzed 7,951 finishers (women, n = 1,236, age 36.7 ± 9.1 years; men, n = 6,715, 40.1 ± 10.1 years) competing in "Powerman Zofingen" from 2003 to 2017. Men were faster than women by 8.2% (171 ± 21 minutes vs. 186 ± 21 minutes, p < 0.001, η2 = 0.068) and 7.5% (502 ± 57 minutes vs. 543 ± 64 minutes, p < 0.001, η2 = 0.068) in the short and long distances, respectively. Women were younger than men by 4.6 years (35.0 ± 9.0 years vs. 39.6 ± 10.5 years, p < 0.001, η2 = 0.026) and 1.8 years (38.8 ± 8.7 years vs. 40.6 ± 9.5 years, p < 0.001, η2 = 0.005) in the short and long distances, respectively. An increase of women finishers across years in the long distance was observed (e.g., n = 19 in 2003 and n = 58 in 2017; p < 0.001), whereas no change was shown in short distance and men finishers. The men-to-women ratio (MWR) decreased across years in the long, but not in the short distance. No change of race time across years was observed. The sex difference in race time increased in long distance (p = 0.014), whereas it did not change in the short. Age increased across years in both sexes and distances (p < 0.001). The sex difference in age decreased in the long (p = 0.007), but not in the short distance. In summary, the number of women finishers increased and the MWR decreased in the long distance. The age of the finishers increased across years, and their performance remained unchanged. The increase of the sex difference in race time in the long distance might be attributed to the increased number of women finishers.

Physiological Responses to Swimming Repetitive "Ice Miles".

ABSTRACT: Knechtle, B, Stjepanovic, M, Knechtle, C, Rosemann, T, Sousa, CV, and Nikolaidis, PT. Physiological responses to swimming repetitive "Ice Miles." J Strength Cond Res 35(2): 487-494, 2021-"Ice Mile" swimming (i.e., 1,608 m in water of below 5° C) is becoming increasingly popular. Since the foundation of the International Ice Swimming Association (IISA) in 2009, official races are held as World Cup Races and World Championships. Ice swimming was a demonstration sport at the 2014 Winter Olympics in Sochi, Russia. This case study aimed to identify core body temperature and selected hematological and biochemical parameters before and after repeated "Ice Miles." An experienced ice swimmer completed 6 consecutive Ice Miles within 2 days. Three Ice Miles adhered to the strict criteria for the definition of Ice Miles, whereas the other 3 were very close (i.e., 5.2, 6.1, and 6.6° C) to the temperature limit. Swimming times, changes in core body temperatures, and selected urinary and hematological parameters were recorded. The athlete showed after each Ice Mile a metabolic acidosis (i.e., an increase in lactate and TCO2; a decrease in base excess and HCO3-) and an increase in blood glucose, cortisol, and creatine kinase concentration. The decrease in pH correlated significantly and negatively with the increase in cortisol level, indicating that this intense exercise causes a metabolic stress. The change in core body temperature between start and finish was negatively associated with metabolic acidosis. The increase in creatine kinase suggests skeletal muscle damages due to shivering after an Ice Mile. For athletes and coaches, swimming in cold water during Ice Miles leads to a metabolic acidosis, which the swimmer tries to compensate with a respiratory response. Considering the increasing popularity of ice swimming, the findings have practical value for swimmers and practitioners (e.g., coaches, exercise physiologists, and physicians) working with them because our results provide a detailed description of acute physiological responses to repeated swimming in cold conditions. These findings are of importance for athletes and coaches for National Championships and World Championships in Ice Swimming following the IISA rules.

Pacing in Long-Distance Running: Sex and Age Differences in 10-km Race and Marathon.

Background and objective: The recent availability of data from mass-participation running events has allowed researchers to examine pacing from the perspective of non-elite distance runners. Based on an extensive analysis of the literature, we concluded that no study utilizing mass-participation events data has ever directly compared pacing in the 10-km race, with other long-distance races. Therefore, the main aim of this study was to assess and compare pacing between 10-km runners and marathoners, in regards to their sex and age. Materials and methods: For the purpose of this study, official results from the Oslo marathon (n = 8828) and 10-km race (n = 16,315) held from 2015 to 2018 were included. Results: Both 10-km runners and marathoners showed positive pacing strategies. Moreover, two-way analysis of variance showed that women were less likely to slow in the marathon than men (9.85% in comparison to 12.70%) however, not in the 10-km race (3.99% in comparison to 3.38%). Finally, pace changing is more prominent in youngest and oldest marathoners comparing to the other age groups (12.55% in comparison to 10.96%). Conclusions: Based on these findings, practitioners should adopt different training programmes for marathoners in comparison to shorter long-distance runners.

Vitamin D and Stress Fractures in Sport: Preventive and Therapeutic Measures-A Narrative Review.

There are numerous risk factors for stress fractures that have been identified in literature. Among different risk factors, a prolonged lack of vitamin D (25(OH)D) can lead to stress fractures in athletes since 25(OH)D insufficiency is associated with an increased incidence of a fracture. A 25(OH)D value of <75.8 nmol/L is a risk factor for a stress fracture. 25(OH)D deficiency is, however, only one of several potential risk factors. Well-documented risk factors for a stress fracture include female sex, white ethnicity, older age, taller stature, lower aerobic fitness, prior physical inactivity, greater amounts of current physical training, thinner bones, 25(OH)D deficiency, iron deficiency, menstrual disturbances, and inadequate intake of 25(OH)D and/or calcium. Stress fractures are not uncommon in athletes and affect around 20% of all competitors. Most athletes with a stress fracture are under 25 years of age. Stress fractures can affect every sporty person, from weekend athletes to top athletes. Stress fractures are common in certain sports disciplines such as basketball, baseball, athletics, rowing, soccer, aerobics, and classical ballet. The lower extremity is increasingly affected for stress fractures with the locations of the tibia, metatarsalia and pelvis. Regarding prevention and therapy, 25(OH)D seems to play an important role. Athletes should have an evaluation of 25(OH)D -dependent calcium homeostasis based on laboratory tests of 25-OH-D3, calcium, creatinine, and parathyroid hormone. In case of a deficiency of 25(OH)D, normal blood levels of ≥30 ng/mL may be restored by optimizing the athlete's lifestyle and, if appropriate, an oral substitution of 25(OH)D. Very recent studies suggested that the prevalence of stress fractures decreased when athletes are supplemented daily with 800 IU 25(OH)D and 2000 mg calcium. Recommendations of daily 25(OH)D intake may go up to 2000 IU of 25(OH)D per day.

Physical Activity Levels and Mental Health during the COVID-19 Pandemic: Preliminary Results of a Comparative Study between Convenience Samples from Brazil and Switzerland.

Background and objectives: It has been suggested that the COVID-19 pandemic impaired people's moods and general levels of physical activity, but the way in which each country is coping with the situation may result in different outcomes. The aim of the present study was to compare the mental health and physical activity levels between residents of Brazil and Switzerland during the social distancing period associated with COVID-19 pandemic. Materials and Methods: A self-administered questionnaire aiming to assess personal, quarantine, physical activity, and mood state disorders data was answered by 114 participants (57 from each country) of both sexes. Results: Swiss participants presented a higher frequency of people (47.4%) not abiding by social distancing measures compared to Brazilian participants (1.8%; p < 0.001, effect size = 0.56). There were no significant differences between the participants from the two countries regarding physical activity levels (p = 0.09). The Swiss presented a higher frequency (78.9%) of people without symptoms of depression compared to Brazilians (31.6%; p < 0.001, effect size = 0.48). The Swiss also presented a higher frequency (77.2%) of people without symptoms of anxiety compared to Brazilians (35.1%; p < 0.001, effect size = 0.43). There was a significant association between the restriction level and depression symptoms (p = 0.01, effect size = 0.25) but not with anxiety symptoms (p = 0.21, effect size = 0.16). Conclusions: According to the preliminary results, Brazilians presented a much higher frequency of depression and anxiety symptoms, which can be explained by characteristics other than the restriction level.

Age-related differences in torque in angle-specific and peak torque hamstring to quadriceps ratios in female soccer players from 11 to 18 years old: Α Cross-sectional study.

The aim of this study was to evaluate and compare the hamstring (H) and quadriceps (Q) strength, bilateral difference and balance ratios in female soccer players. Ninety-three athletes from three age groups: under 13 (U13), 15 (U15) and 18 (U18) participated in the study performing isokinetic tests to measure peak torque, total work, average power and torque at 30º of thigh muscles. Conventional strength balance ratios, angle-specific balance ratio and bilateral strength difference were evaluated. There was bilateral strength difference for extensor muscles total work (p = 0.02) in U13 and flexor muscles peak torque (p = 0.02) in U15. All variables were superior in U15 than U13 (p <.05). There was no strength difference between U15 and U18. Balance ratios did not differ between sides or age groups. The study showed that although peak torque values were higher in U15 than in U13, balance ratios were similar.

The influence of chlorine in indoor swimming pools on the composition of breathing phase of professional swimmers.

OBJECTIVES: Swimming is one of the most popular forms of physical activity. Pool water is cleaned with chlorine, which - in combination with compounds contained in water - could form chloramines and trichloromethane in the swimmer's lungs. The aim of the present study was to examine the effect of swimming training in an indoor pool on the composition of swimmers' respiratory phase metabolomics, and develop a system to provide basic information about its impact on the swimmer's airway mucosa metabolism, which could help to assess the risk of secondary respiratory tract diseases i.e. sport results, condition, and health including lung acute and chronic diseases). DESIGN: A group of competitive swimmers participated in the study and samples of their respiratory phase before training, immediately after training, and 2 h after training were assessed. METHODS: Sixteen male national and international-level competitive swimmers participated in this study. Respiratory phase analysis of the indoor swimming pool swimmers was performed. Gas chromatography combined with mass spectrometry (GCMS) was used in the measurements. All collected data were transferred to numerical analysis for trends of tracking and mapping. The breathing phase was collected on special porous material and analyzed using GCMS headspace. RESULTS: The obtained samples of exhaled air were composed of significantly different metabolomics when compared before, during and after exercise training. This suggests that exposition to indoor chlorine causes changes in the airway mucosa. CONCLUSION: This phenomenon may be explained by occurrence of a chlorine-initiated bio-reaction in the swimmers' lungs. The obtained results indicate that chromatographic exhaled gas analysis is a sensitive method of pulmonary metabolomic changes assessment. Presented analysis of swimmers exhaled air indicates, that indoor swimming may be responsible for airway irritation caused by volatile chlorine compounds and their influence on lung metabolism.

Effects of a 30 min nap opportunity on cognitive and short-duration high-intensity performances and mood states after a partial sleep deprivation night.

This study evaluated the effects of partial-sleep-deprivation (SDN) and a 30 min nap opportunity on physical and cognitive performances and mood states. Fourteen physically active students (BMI = 232.8 ± 0.4 kg/m2) performed the reaction time, the number cancellation (i.e., assessing vigilance) and the 5-m shuttle run tests and responded to the Profile of Mood States (POMS-f) questionnaire at 18h00 after a normal-sleep (NSN) and a SDN) and after two nap conditions (Nap and no-Nap) realized between 13h00 and 13h30. Vigilance and the reaction time were better after Nap compared to no-Nap opportunity following NSN and SDN and during NSN compared to SDN only during no-Nap. Total and peak distance during the 5-m shuttle run test were higher and the fatigue index was lower during Nap compared to no-Nap condition after NSN and SDN and during NSN compared to SDN during Nap and no-Nnap. Anxiety, fatigue, confusion, and depression were lower and vigour was higher during Nap compared to no-Nap after NSN and SDN and during NSN compared to SDN during Nap and no-Nap. In conclusion, a 30-min of nap opportunity helps to overcome the negative effect of SDN on mood states as well as physical and cognitive performances.

Performance in 100-km Ultramarathoners-At Which Age, It Reaches Its Peak?

Nikolaidis, PT and Knechtle, B. Performance in 100-km ultramarathoners-At which age, it reaches its peak? J Strength Cond Res 34(5): 1409-1415, 2020-The number of those participating in 100-km ultramarathon has increased over the past years; however, we have limited knowledge about performance trends in this sport, and particularly, the effect of age. The aim of this study was to analyze the age when women and men runners achieve their peak performance considering 1- and 5-year age group intervals, and examining all or the fastest (i.e., top 10) participants in each age group. We analyzed 370,051 athletes (i.e., 44,601 women and 325,450 men) who finished a 100-km ultramarathon between 1959 and 2016, and studied the age of peak performance using a second-order nonlinear regression analysis. The age of peak performance was 40-44 years in women and 45-49 years in men when all finishers were analyzed, whereas it was 30-34 years in women and 35-39 years in men when the top 10 finishers were considered in 5-year age groups. When we analyzed finishers in 1-year age groups, we found the age of peak performance at 41 years in women and 45 years in men considering all finishers, and at 39 years in women and 41 years in men considering the top 10 finishers. In conclusion, the age of peak performance was younger in women than in men, which might reflect the overall younger age of women participants than men. Compared with previous studies, we observed the peak performance at an age older by ∼10 years, which could be attributed to an increase of finishers' age across calendar years. Because the knowledge of the age of peak performance is unique for each sport, coaches and fitness trainers might benefit from the findings of this study in the long-term training of their athletes.