Explore the vast range of titles available.

VO 2 max (maximal oxygen consumption), a validated measure of aerobic fitness, has been associated with better cerebral artery compliance and measures of brain morphology, such as higher cortical thickness (CT) in frontal, temporal and cingular cortices, and larger grey matter volume (GMV) of the middle temporal gyrus, hippocampus, orbitofrontal cortex and cingulate cortex. Single sessions of physical exercise can promptly enhance cognitive performance and brain activity during executive tasks. However, the immediate effects of exercise on macro-scale properties of the brain's grey matter remain unclear. We investigated the impact of one session of moderate-intensity physical exercise, compared with rest, on grey matter volume, cortical thickness, working memory performance, and task-related brain activity in older adults. Cross-sectional associations between brain measures and VO 2 max were also tested. Exercise did not induce statistically significant changes in brain activity, grey matter volume, or cortical thickness. Cardiovascular fitness, measured by VO 2 max, was associated with lower grey matter blood flow in the left hippocampus and thicker cortex in the left superior temporal gyrus. Cortical thickness was reduced at post-test independent of exercise/rest. Our findings support that (1) fitter individuals may need lower grey matter blood flow to meet metabolic oxygen demand, and (2) have thicker cortex.

To examine the dose–response relationship between moderate-to-vigorous physical activity (MVPA) and sitting time trajectories with cardiac and all-cause mortality in a cohort of middle-aged and older-adults after a diagnosis of coronary heart disease (CHD). This prospective cohort study comprised Australian participants aged ≥45-years with CHD (2006–2020) who had self-reported MVPA (min/wk) and sitting time (hr/day) data from at least two survey waves. MVPA and sitting time trajectories were categorised as remaining high, decreasing, increasing, and remaining low. Cardiac and all-cause mortality were the main outcomes. Associations were explored using Cox regression models. The cohort included 9430 participants (mean (SD) age, 70 (10) years; 3557 females (38 %)). During a median follow-up of 4.4 (IQR, 6.1) years, 540 cardiac and 2843 all-cause deaths were recorded. Compared with individuals that remained inactive, remaining active was associated with a 36 % and 49 % lower risk of cardiac and all-cause death, respectively. Decreasing or increasing MVPA over time was associated with a 20–33 % lower risk of all-cause death. Compared with high sitting time, individuals that maintained low sitting time or decreased their sitting time over time reduced the associated risk of cardiac and all-cause death by 33–38 %. Regardless of pre-CHD diagnosis movement behaviours, individuals' post-CHD diagnosis can reduce their risk of cardiac and all-cause mortality by achieving the physical activity thresholds at any time and reducing their sitting time over-time. Further research is needed to confirm the physical activity and sitting time thresholds to receive these benefits.

Inter-limb differences in Achilles tendon mechanical, material and morphological properties have previously been described in non-athletes and attributed to the preferential use of a given limb. Achilles tendon overuse tendon injury generally initiate unilaterally and alters triceps surae activation and Achilles tendon properties. The investigation of inter-limb differences in muscle activation and tendon properties may provide directions for injury prevention in habitual runners. In this study triceps surae and Achilles tendon properties were investigated bilaterally in habitual runners during unilateral maximal isometric contractions. Morphological, mechanical and material Achilles tendon properties were assessed using isokinetic dynamometry, motion capture and ultrasonography while triceps surae activation strategies were assessed using electromyography. Lower limb preference was assessed for inter-limb comparisons using the Waterloo questionnaire. Zero and one-dimensional statistical analysis and Cohen’s d were employed to investigate possible inter-limb differences. Inter-limb associations in Achilles tendon properties and intra-limb associations between triceps surae activations were assessed using Pearson’s correlation coefficients. No differences were observed between the preferred and non-preferred limb in terms of triceps surae muscle activation amplitude and Achilles tendon properties. However, intra-limb association among triceps surae activation ratios were not identical between limbs. Runners and triathletes present similar Achilles tendons properties between limbs, and thus initial observations of unilateral changes in the Achilles tendon properties might be used as a strategy to prevent the onset of overuse tendon injury. The non-similar associations within activation ratios between limbs should be further explored since triceps surae activation strategies may alter loading of the Achilles tendon.

Background The effect of concurrent training on the development of maximal strength is unclear, especially in individuals with different training statuses. Objective The aim of this systematic review and meta-analysis study was to compare the effect of concurrent resistance and endurance training with that of resistance training only on the development of maximal dynamic strength in untrained, moderately trained, and trained individuals. Methods On the basis of the predetermined criteria, 27 studies that compared effects between concurrent and resistance training only on lower-body 1-repetition maximum (1RM) strength were included. The effect size (ES), calculated as the standardised difference in mean, was extracted from each study, pooled, and analysed with a random-effects model. Results The 1RM for leg press and squat exercises was negatively affected by concurrent training in trained individuals (ES =  – 0.35, p  < 0.01), but not in moderately trained ( – 0.20, p  = 0.08) or untrained individuals (ES = 0.03, p  = 0.87) as compared to resistance training only. A subgroup analysis revealed that the negative effect observed in trained individuals occurred only when resistance and endurance training were conducted within the same training session (ES same session =  – 0.66, p  < 0.01 vs. ES different sessions =  – 0.10, p  = 0.55). Conclusion This study demonstrated the novel and quantifiable effects of training status on lower-body strength development and shows that the addition of endurance training to a resistance training programme may have a negative impact on lower-body strength development in trained, but not in moderately trained or untrained individuals. This impairment seems to be more pronounced when training is performed within the same session than in different sessions. Trained individuals should therefore consider separating endurance from resistance training during periods where the development of dynamic maximal strength is prioritised.

Sudden cardiac death (SCD) is the leading cause of death in athletes during sport. Whether obtained for screening or diagnostic purposes, an ECG increases the ability to detect underlying cardiovascular conditions that may increase the risk for SCD. In most countries, there is a shortage of physician expertise in the interpretation of an athlete's ECG. A critical need exists for physician education in modern ECG interpretation that distinguishes normal physiological adaptations in athletes from abnormal findings suggestive of pathology. On 13–14 February 2012, an international group of experts in sports cardiology and sports medicine convened in Seattle, Washington, to define contemporary standards for ECG interpretation in athletes. The objective of the meeting was to develop a comprehensive training resource to help physicians distinguish normal ECG alterations in athletes from abnormal ECG findings that require additional evaluation for conditions associated with SCD.

AIMS: Physical activity (PA) used as prevention and treatment of disease has created a need for effective tools for measuring patients' PA level. Our aim was therefore to assess the validity of two PA questions and their three associated answer modes. METHODS: Data on PA according to the PA questions and Actigraph GT3X+ accelerometers, aerobic fitness (VO 2 max), cardiovascular biomarkers, and self-rated general health were collected in 365 Swedish adults (21-66 years). The PA questions ask about weekly PA via categories (Categorical), an open-ended answer (Open), or specified day by day (Table). RESULTS: The Categorical mode, compared with the Open mode, correlated (Spearman's rho) significantly more strongly (p<0.05) with accelerometer PA (0.31 vs. 0.18) and VO 2 max (0.27 vs. 0.06), and the level of BMI (-0.20 vs. -0.02), waist circumference (-0.22 vs. -0.03), diastolic blood pressure (-0.16 vs. 0.08), glucose (-0.18 vs. 0.04), triglycerides (-0.31 vs. -0.07), and general health (0.35 vs. 0.19). The validity of the Categorical and Table modes were similar regarding VO 2 max and accelerometry, but the Categorical mode exhibited more significant and stronger correlations with cardiovascular biomarkers. The capacity of the PA questions to identify insufficiently physically active individuals ranged from 0.57 to 0.76 for sensitivity and from 0.47 to 0.79 for specificity. CONCLUSIONS: The Categorical mode exhibits the strongest validity and Open mode the weakest. The PA questions may be used on a population level, or as a tool for determining patents' appropriateness for treatment.

The ability to measure physical activity through wrist-worn devices provides an opportunity for cardiovascular medicine. However, the accuracy of commercial devices is largely unknown. The aim of this work is to assess the accuracy of seven commercially available wrist-worn devices in estimating heart rate (HR) and energy expenditure (EE) and to propose a wearable sensor evaluation framework. We evaluated the Apple Watch, Basis Peak, Fitbit Surge, Microsoft Band, Mio Alpha 2, PulseOn, and Samsung Gear S2. Participants wore devices while being simultaneously assessed with continuous telemetry and indirect calorimetry while sitting, walking, running, and cycling. Sixty volunteers (29 male, 31 female, age 38 ± 11 years) of diverse age, height, weight, skin tone, and fitness level were selected. Error in HR and EE was computed for each subject/device/activity combination. Devices reported the lowest error for cycling and the highest for walking. Device error was higher for males, greater body mass index, darker skin tone, and walking. Six of the devices achieved a median error for HR below 5% during cycling. No device achieved an error in EE below 20 percent. The Apple Watch achieved the lowest overall error in both HR and EE, while the Samsung Gear S2 reported the highest. In conclusion, most wrist-worn devices adequately measure HR in laboratory-based activities, but poorly estimate EE, suggesting caution in the use of EE measurements as part of health improvement programs. We propose reference standards for the validation of consumer health devices (http://precision.stanford.edu/).

Introduction Dietary inorganic nitrate is a popular nutritional supplement, which increases nitric oxide bioavailability and may improve exercise performance. Despite over a decade of research into the effects of dietary nitrate supplementation during exercise there is currently no expert consensus on how, when and for whom this compound could be recommended as an ergogenic aid. Moreover, there is no consensus on the safe administration of dietary nitrate as an ergogenic aid. This study aimed to address these research gaps. Methods The modified Delphi technique was used to establish the views of 12 expert panel members on the use of dietary nitrate as an ergogenic aid. Over three iterative rounds (two via questionnaire and one via videoconferencing), the expert panel members voted on 222 statements relating to dietary nitrate as an ergogenic aid. Consensus was reached when > 80% of the panel provided the same answer (i.e. yes or no). Statements for which > 80% of the panel cast a vote of insufficient evidence were categorised as such and removed from further voting. These statements were subsequently used to identify directions for future research. Results The 12 panel members contributed to voting in all three rounds. A total of 39 statements (17.6%) reached consensus across the three rounds (20 yes, 19 no). In round one, 21 statements reached consensus (11 yes, 10 no). In round two, seven further statements reached consensus (4 yes, 3 no). In round three, an additional 11 statements reached consensus (5 yes, 6 no). The panel agreed that there was insufficient evidence for 134 (60.4%) of the statements, and were unable to agree on the outcome of the remaining statements. Conclusions This study provides information on the current expert consensus on dietary nitrate, which may be of value to athletes, coaches, practitioners and researchers. The effects of dietary nitrate appear to be diminished in individuals with a higher aerobic fitness (peak oxygen consumption [ V̇ O 2peak ] > 60 ml/kg/min), and therefore, aerobic fitness should be taken into account when considering use of dietary nitrate as an ergogenic aid. It is recommended that athletes looking to benefit from dietary nitrate supplementation should consume 8–16 mmol nitrate acutely or 4–16 mmol/day nitrate chronically (with the final dose ingested 2–4 h pre-exercise) to maximise ergogenic effects, taking into consideration that, from a safety perspective, athletes may be best advised to increase their intake of nitrate via vegetables and vegetable juices. Acute nitrate supplementation up to ~ 16 mmol is believed to be safe, although the safety of chronic nitrate supplementation requires further investigation. The expert panel agreed that there was insufficient evidence for most of the appraised statements, highlighting the need for future research in this area. Graphical Abstract

Blood glucose regulation has been studied for well over a century as it is intimately related to metabolic health. Research in glucose transport and uptake has also been substantial within the field of exercise physiology as glucose delivery to the working muscles affects exercise capacity and athletic achievements. However, although exceptions exist, less focus has been on blood glucose as a parameter to optimize training and competition outcomes in athletes with normal glucose control. During the last years, measuring glucose has gained popularity within the sports community and successful endurance athletes have been seen with skin-mounted sensors for continuous glucose monitoring (CGM). The technique offers real-time recording of glucose concentrations in the interstitium, which is assumed to be equivalent to concentrations in the blood. Although continuous measurements of a parameter that is intimately connected to metabolism and health can seem appealing, there is no current consensus on how to interpret measurements within this context. Well-defined approaches to use glucose monitoring to improve endurance athletes’ performance and health are lacking. In several studies, blood glucose regulation in endurance athletes has been shown to differ from that in healthy controls. Furthermore, endurance athletes regularly perform demanding training sessions and can be exposed to high or low energy and/or carbohydrate availability, which can affect blood glucose levels and regulation. In this current opinion, we aim to discuss blood glucose regulation in endurance athletes and highlight the existing research on glucose monitoring for performance and health in this population.