The potential of blood flow restriction exercise to overcome Jetlag : important implications for Tokyo 2020

The decision taken by the International Olympic Committee (IOC) to host the Olympic Games this summer brings new challenges for event organisers and athletes. One such measure taken by the IOC is to mandate that athletes may not enter the Olympic Village more than five days before competing at the Games in order to prevent the spread of COVID-19. As a result, athletes from around the globe that are unable to make alternative plans will need to travel to Tokyo and acclimatize within only 5 days before their event. Of particular concern are the adverse health and performance effects elicited by flight dysrhythmia, also known as jetlag, on those athletes travelling to the Olympic Games across multiple times zones. Blood flow restriction (BFR) is a safe exercise mode that can potentially diminish the impact of jetlag on performance through its numerous beneficial physiological adaptations that overlap with those of other jetlag mitigation strategies. Experimental data are required to confirm this intriguing possibility. The present commentary aims to encourage more research into the effects of BFR training in conjunction with other strategies to overcome the effects of jetlag prior, during and after a long-haul flight on the subsequent performance of elite athletes, particularly during these difficult times of the COVID19 pandemic.https://www.minervamedica.it/en/journals/medicina-dello-sport2022-07-17hj2021Sports Medicin

Recommendations for Face Coverings While Exercising During the COVID-19 Pandemic

In an effort to reduce transmission and number of infections of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2 or COVID-19) virus, governments and official bodies around the world have produced guidelines on the use of face masks and face coverings. While there is a growing body of recommendations for healthcare professionals and the wider population to use facial protection in “enclosed spaces” where minimal distancing from other individuals is not possible, there is a dearth of clear guidelines for individuals undertaking exercise and sporting activity. The present viewpoint aims to propose recommendations for face coverings while exercising during the COVID-19 pandemic that consider physical distancing, the environment, the density of active cases associated with the specific sports activity, and the practical use of face coverings in order to reduce potential viral transmission. Recommendations are provided on the basis of very limited available evidence in conjunction with the extensive collective clinical experience of the authors and acknowledging the need to consider the likelihood of the presence of the SARS-CoV-2 in the general population. We recommend that face coverings should be used in any environment considered to be of a high or moderate transmission risk, where tolerated and after individual risk assessment. In addition, as national caseloads fluctuate, individual sporting bodies should consider up to date guidance on the use of face coverings during sport and exercise, alongside other preventative measures

Extremely short duration high intensity interval training substantially improves insulin action in young healthy males

Background: Traditional high volume aerobic exercise training reduces cardiovascular and metabolic disease risk but involves a substantial time commitment. Extremely low volume high-intensity interval training (HIT) has recently been demonstrated to produce improvements to aerobic function, but it is unknown whether HIT has the capacity to improve insulin action and hence glycemic control. Methods: Sixteen young men (age: 21 ± 2 y; BMI: 23.7 ± 3.1 kg·m-2; VO2peak: 48 ± 9 ml·kg-1·min-1) performed 2 weeks of supervised HIT comprising of a total of 15 min of exercise (6 sessions; 4-6 × 30-s cycle sprints per session). Aerobic performance (250-kJ self-paced cycling time trial), and glucose, insulin and NEFA responses to a 75-g oral glucose load (oral glucose tolerance test; OGTT) were determined before and after training. Results: Following 2 weeks of HIT, the area under the plasma glucose, insulin and NEFA concentration-time curves were all reduced (12%, 37%, 26% respectively, all P < 0.001). Fasting plasma insulin and glucose concentrations remained unchanged, but there was a tendency for reduced fasting plasma NEFA concentrations post-training (pre: 350 ± 36 v post: 290 ± 39 μmol·l-1, P = 0.058). Insulin sensitivity, as measured by the Cederholm index, was improved by 23% (P < 0.01), while aerobic cycling performance improved by ∼6% (P < 0.01). Conclusion: The efficacy of a high intensity exercise protocol, involving only ∼250 kcal of work each week, to substantially improve insulin action in young sedentary subjects is remarkable. This novel time-efficient training paradigm can be used as a strategy to reduce metabolic risk factors in young and middle aged sedentary populations who otherwise would not adhere to time consuming traditional aerobic exercise regimes

Commentaries on viewpoint : physiology and fast marathons

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Strength, power and aerobic capacity of transgender athletes:a cross-sectional study

OBJECTIVE: The primary objective of this cross-sectional study was to compare standard laboratory performance metrics of transgender athletes to cisgender athletes.METHODS: 19 cisgender men (CM) (mean±SD, age: 37±9 years), 12 transgender men (TM) (age: 34±7 years), 23 transgender women (TW) (age: 34±10 years) and 21 cisgender women (CW) (age: 30±9 years) underwent a series of standard laboratory performance tests, including body composition, lung function, cardiopulmonary exercise testing, strength and lower body power. Haemoglobin concentration in capillary blood and testosterone and oestradiol in serum were also measured.RESULTS: In this cohort of athletes, TW had similar testosterone concentration (TW 0.7±0.5 nmol/L, CW 0.9±0.4 nmol/), higher oestrogen (TW 742.4±801.9 pmol/L, CW 336.0±266.3 pmol/L, p=0.045), higher absolute handgrip strength (TW 40.7±6.8 kg, CW 34.2±3.7 kg, p=0.01), lower forced expiratory volume in 1 s:forced vital capacity ratio (TW 0.83±0.07, CW 0.88±0.04, p=0.04), lower relative jump height (TW 0.7±0.2 cm/kg; CW 1.0±0.2 cm/kg, p&lt;0.001) and lower relative V̇O 2max (TW 45.1±13.3 mL/kg/min/, CW 54.1±6.0 mL/kg/min, p&lt;0.001) compared with CW athletes. TM had similar testosterone concentration (TM 20.5±5.8 nmol/L, CM 24.8±12.3 nmol/L), lower absolute hand grip strength (TM 38.8±7.5 kg, CM 45.7±6.9 kg, p =0.03) and lower absolute V̇O 2max (TM 3635±644 mL/min, CM 4467±641 mL/min p =0.002) than CM. CONCLUSION: While longitudinal transitioning studies of transgender athletes are urgently needed, these results should caution against precautionary bans and sport eligibility exclusions that are not based on sport-specific (or sport-relevant) research.</p

Resolution of habitat-associated ecogenomic signatures in bacteriophage genomes and application to microbial source tracking

Just as the expansion in genome sequencing has revealed and permitted the exploitation of phylogenetic signals embedded in bacterial genomes, the application of metagenomics has begun to provide similar insights at the ecosystem-level for microbial communities. However, little is known regarding this aspect of bacteriophage associated with microbial ecosystems, and if phage encode discernible habitat-associated signals diagnostic of underlying microbiomes. Here we demonstrate that individual phage can encode clear habitat-related “ecogenomic signatures”, based on relative representation of phage encoded gene homologues in metagenomic datasets. Furthermore, we show the  ecogenomic signature encoded by the gut-associated ɸB124-14 can be used to segregate metagenomes according to environmental origin, and distinguish “contaminated” environmental metagenomes (subject to simulated in silico human faecal pollution) from uncontaminated datasets. This indicates phage encoded ecological signals likely possess sufficient discriminatory power for use in biotechnological applications, such as development of microbial source tracking tools for monitoring water quality