The effect of a single dose of beetroot juice on speed, strength, and power in healthy recreationally active females.

Nitrate-rich beetroot juice (BR) improves muscle contraction which is relevant for intense intermittent-type sports. However, few studies have examined the effect of BR ingestion on performance using sport-specific exercise protocols. Moreover, there is a scarcity of research that include female participants which limits real world application given that females potentially have different responses to BR ingestion. The purpose of the present study was to examine the effect of BR supplementation on speed, acceleration, strength and power before and after fatigue in females. In a double-blind, randomized crossover design, 15 recreationally active females consumed BR and nitrate-depleted placebo juice (PL) ~2.5 hours prior to exercise testing. Measurements included 20 m sprint and acceleration using timing gates, strength using isokinetic handgrip dynamometry, and upper and lower body power using the medicine ball power throw and countermovement jump (CMJ) before and after a fatiguing running protocol. Data from a subset of participants (n=15) were analyzed and revealed no significant difference between PL and BR for 20 m speed and 10 m acceleration (P\u3e0.05), isokinetic handgrip dynamometry (PL: PRE: 76±10 vs POST: 76±13; BR: PRE: 78±12 vs POST: 78±12 lb; P\u3e0.05), medicine ball power throw (PL: PRE: 4.45±0.48 vs POST: 4.35±0.48; BR: PRE: 4.41±0.38 vs POST: 4.49±0.47 m; P\u3e0.05) or CMJ (PL: PRE: 1.72±0.27 vs POST: 1.7±0.26; BR: PRE: 1.77±0.25 vs POST: 1.73±0.28 m; P\u3e0.05). These results indicate that there are no effects of BR supplementation on exercise performance in female athletes; however, this study is currently underpowered, and research is still in progress

The effects of nitrate-rich beetroot juice supplementation on nonverbal executive function in healthy recreationally active females

Nitrate-rich beetroot juice (BR) supplementation has been reported to preserve executive function (i.e. decision making and reaction time) before and after a simulated soccer match in recreationally active males, which may be due to enhanced cerebral blood flow. However, the literature examining the physiological response following BR ingestion in females is scarce, which hampers the extrapolation of results since physiological sex-differences may exist. Therefore, the purpose of this study was to assess if BR ingestion influenced executive function in an unfatigued and fatigued state in healthy recreationally active females. In a double-blind, randomized crossover design, 20 females consumed 140 mL of concentrated BR or nitrate-depleted placebo juice (PL) approximately 2.5 hours prior to each experimental visit. The Delis-Kaplan Executive Function (D-KEF) test, used for assessing higher-level cognitive function, was administered before and after completing a high-intensity intermittent running protocol. The D-KEF test involved 3 x 60-s conditions evaluating various cognitive tasks. A two-way repeated measures analysis of variance was conducted (n=15) and revealed no significant differences in executive function between PL (PRE: 15.27 ± 32.71 vs. POST: 16.93 ± 1.44) and BR (PRE: 15.80 ± 2.65 vs. POST: 16.60 ± 1.88). These preliminary data suggest that acute BR ingestion does not have an influence on processing and creative thinking of nonverbal executive function in an unfatigued or fatigued state in healthy recreationally active females, although importantly, the study is still in progress

The Effects of Acute Beetroot Juice Ingestion on Exercise and Cognitive Performance in Female Athletes

Nitrate-rich beetroot juice can enhance intense exercise performance which is attributed to enhanced skeletal muscle contractility. However, limited data exist in females and it is unknown whether dietary nitrate has an ergogenic effect in this population. PURPOSE: To investigate the potential effects of acute nitrate ingestion on a battery of exercise performance and cognitive tests before and after fatiguing intermittent running exercise. METHODS: Fifteen female team-sport athletes were assigned in a randomized, double-blind, crossover design to consume nitrate-rich beetroot juice (BR; 12 mmol of nitrate) and nitrate-depleted beetroot juice (PL; 0.10 mmol of nitrate) 2.5 h prior to performing the exercise protocol, with a washout period of 7 days between trials. Running 10 m and 20 m sprint split times, sprint reaction time, upper- and lower-body power, handgrip strength, and cognitive flexibility were measured before and after the Yo-Yo intermittent recovery level 1 (Yo-Yo IR1) test, during which performance and rate of perceived exertion were recorded. RESULTS: There were no significant differences in any performance outcome or cognitive flexibility (P \u3e 0.05). CONCLUSION: These findings indicate that acute nitrate ingestion does not influence performance in sprints, intermittent running, power, strength, or cognitive function in young adult female team-sport athletes

Effects of Dietary Nitrate Supplementation on Performance and Muscle Oxygenation during Resistance Exercise in Men

The purpose of the current study was to assess the effects of acute and short-term nitrate (NO3−)-rich beetroot juice (BR) supplementation on performance outcomes and muscle oxygenation during bench press and back squat exercise. Fourteen recreationally active males were assigned in a randomized, double-blind, crossover design to supplement for 4 days in two conditions: (1) NO3−-depleted beetroot juice (PL; 0.10 mmol NO3− per day) and (2) BR (11.8 mmol NO3− per day). On days 1 and 4 of the supplementation periods, participants completed 2 sets of 2 × 70%1RM interspersed by 2 min of recovery, followed by one set of repetitions-to-failure (RTF) at 60%1RM for the determination of muscular power, velocity, and endurance. Quadriceps and pectoralis major tissue saturation index (TSI) were measured throughout exercise. Plasma [NO3−] and nitrite ([NO2−]) were higher after 1 and 4 days of supplementation with BR compared to PL (p \u3c 0.05). Quadriceps and pectoralis major TSI were not different between conditions (p \u3e 0.05). The number of RTF in bench press was 5% greater after acute BR ingestion compared to PL (PL: 23 ± 4 vs. BR: 24 ± 5, p \u3c 0.05). There were no differences between BR and PL for RTF for back squat or power and velocity for back squat or bench press (p \u3e 0.05). These data improve understanding on the ergogenic potential of BR supplementation during resistance exercise

The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance

INTRODUCTION Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic. RATIONALE We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs). RESULTS Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants. CONCLUSION Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

Effects of Dietary Nitrate Supplementation on Performance and Muscle Oxygenation during Resistance Exercise in Men

The purpose of the current study was to assess the effects of acute and short-term nitrate (NO3−)-rich beetroot juice (BR) supplementation on performance outcomes and muscle oxygenation during bench press and back squat exercise. Fourteen recreationally active males were assigned in a randomized, double-blind, crossover design to supplement for 4 days in two conditions: (1) NO3−-depleted beetroot juice (PL; 0.10 mmol NO3− per day) and (2) BR (11.8 mmol NO3− per day). On days 1 and 4 of the supplementation periods, participants completed 2 sets of 2 × 70%1RM interspersed by 2 min of recovery, followed by one set of repetitions-to-failure (RTF) at 60%1RM for the determination of muscular power, velocity, and endurance. Quadriceps and pectoralis major tissue saturation index (TSI) were measured throughout exercise. Plasma [NO3−] and nitrite ([NO2−]) were higher after 1 and 4 days of supplementation with BR compared to PL (p 0.05). The number of RTF in bench press was 5% greater after acute BR ingestion compared to PL (PL: 23 ± 4 vs. BR: 24 ± 5, p 0.05). These data improve understanding on the ergogenic potential of BR supplementation during resistance exercise

Effects of dietary nitrate supplementation on performance and muscle oxygenation during resistance exercise in men

The purpose of the current study was to assess the effects of acute and short-term nitrate (NO3−)-rich beetroot juice (BR) supplementation on performance outcomes and muscle oxygenation during bench press and back squat exercise. Fourteen recreationally active males were assigned in a randomized, double-blind, crossover design to supplement for 4 days in two conditions: (1) NO3−-depleted beetroot juice (PL; 0.10 mmol NO3− per day) and (2) BR (11.8 mmol NO3− per day). On days 1 and 4 of the supplementation periods, participants completed 2 sets of 2 × 70%1RM interspersed by 2 min of recovery, followed by one set of repetitions-to-failure (RTF) at 60%1RM for the determination of muscular power, velocity, and endurance. Quadriceps and pectoralis major tissue saturation index (TSI) were measured throughout exercise. Plasma [NO3−] and nitrite ([NO2−]) were higher after 1 and 4 days of supplementation with BR compared to PL (p 0.05). The number of RTF in bench press was 5% greater after acute BR ingestion compared to PL (PL: 23 ± 4 vs. BR: 24 ± 5, p 0.05). These data improve understanding on the ergogenic potential of BR supplementation during resistance exercise.</p