No evidence of improvements in energy metabolism after 1 week of nitrate and citrulline co-supplementation in elite rowers.

PURPOSE: Citrulline (CIT) and beetroot extract (BR) supplements positively impacts exercise performance in elite rowers. However, its influence on metabolic outcomes such as whole-body volumes of oxygen consumption (VO2) and carbon dioxide production (VCO2), substrate oxidation, energy expenditure (EE), and gross efficiency remains unknown. We studied the effects of 1 week of daily co-supplementation of 3.5 g BR (500 mg NO3-) plus 6 g CIT on VO2 and VCO2 kinetics, substrate utilization, EE, and gross efficiency in elite male rowers compared to a placebo and to a BR supplementation. METHODS: Twenty elite rowers participated in this randomized, double-blind, placebo-controlled crossover trial completing 1 week of supplementation in each group of study: Placebo (PLAG); BRG; and BR-CITG. Efficiency (70% VO2max) and performance (incremental maximal) tests were performed, and gas-exchange data were collected via indirect calorimetry. RESULTS: Analysis of covariance (ANCOVA) showed no mean between-condition differences on respiratory exchange ratio (RER), EE, and gross efficiency in the efficiency test (all P > 0.06), and in the performance test (all P > 0.28). Moreover, in both tests no interaction Time × Supplement effects were observed for VO2, VCO2, RER, EE, substrate oxidation, and, gross efficiency (all P > 0.12). CONCLUSION: After 1 week, no effects on energy metabolism and substrate utilization were observed after the daily co-ingestion of BR extract plus CIT supplement, therefore longer (> 7 days) and higher doses of supplementation might be needed to influence metabolism.

Low-volume combined aerobic and resistance high-intensity interval training in type 2 diabetes: a randomised controlled trial.

Objective: The objective of this study was to compare the effects of novel, time-efficient, low-volume combined aerobic and resistance high-intensity interval training (C-HIIT), and current exercise guidelines (210 min/week of combined moderate-intensity continuous training (C-MICT)), with waitlist control (CON) on glycaemic control in people with type 2 diabetes mellitus (T2D). Methods: Sixty-nine low-active people with T2D were randomised to 8 weeks of supervised C-HIIT (78 min/week), supervised C-MICT (210 min/week), or waitlist CON. Those in waitlist CON were re-randomised to supervised C-HIIT/C-MICT at week 8. Following 8 weeks of supervised training, participants completed 10 months of self-directed exercise. Outcomes were assessed at baseline, week 8 and month 12. Participants in waitlist CON were only included in the exercise groups for the month 12 analysis. Analyses were completed using intention-to-treat analysis of covariance (n=69; week 8) and linear mixed modelling (n=63; month 12). Results: Compared with CON, at week 8, HbA1c decreased in C-HIIT (adjusted mean difference: -0.7% (95% CI -1.3, -0.2%)) and C-MICT (-1.2% (-1.9, -0.6%)). There were also improvements in C-HIIT and C-MICT versus CON at week 8 for fat mass (-1.9 (-3.1, -0.6) and -1.5 (-2.6, -0.4) kg, respectively), lean mass (1.5 (0.8, 2.3) and 0.9 (0.1, 1.7) kg), and exercise capacity (124 (77, 171) and 49 (5, 93) s). At month 12, adherence was low, and most measures returned to baseline. Conclusions: Low-volume C-HIIT (78 min/week) and C-MICT (210 min/week) improved glycaemic control, body composition and exercise capacity similarly over 8 weeks in people with T2D. However, at month 12, improvements were not maintained following self-directed exercise. Regardless, these data suggest that supervised low-volume C-HIIT is a time-efficient and effective strategy for improving outcomes in T2D.

Determining the Levels of Cortisol, Testosterone, Lactic Acid and Anaerobic Performance in Athletes Using Various Forms of Coffee.

BACKGROUND: Coffee is considered one of the most preferred and consumed beverage types in the world, and caffeine is known to increase physical performance due to its ergogenic properties. The aim of this study is to examine the effects of coffee consumption in different forms on cortisol, testosterone, lactic acid and anaerobic performance levels. METHODS: A total of 15 licensed male football players participated in the research voluntarily. The research was implemented in a single-blind, counterbalanced, randomized and crossover study design. Participants were given caffeinated coffee (CK), decaffeinated coffee (placebo) (DK), powdered caffeine (in a gelatin capsule) (PC) and powdered placebo (maltodextrin in a capsule) (PM) on different days, and the Wingate test protocol was performed after the warm-up protocol. Blood samples were collected post-test. Cortisol, testosterone and lactic acid levels in the serum samples taken were determined by the ELISA method. RESULTS: As a result, it was revealed that caffeinated coffee given to participants who exercise increased anaerobic power. However, it was observed that lactic acid levels were higher in placebo and decaffeinated coffee. The highest level of cortisol was found in caffeinated coffee and powdered caffeine compared to the placebo. Testosterone values were observed to be highest in caffeinated coffee and decaffeinated coffee compared to a placebo. CONCLUSIONS: The study suggests that the type of caffeine is a factor that affects absorption rate, which impacts performance and hormone levels.

The Effectiveness and Validity of Inspiratory Muscle Training in the Training Process of Disabled Swimmers.

Objectives: The aim of this study was to evaluate the effect of medium-intensity inspiratory muscle training added to standard swimming training on inspiratory muscle strength and aerobic endurance levels and training status in disabled swimming athletes. Methods: This study involved 16 disabled athletes: group I-athletes performing swimming training with 8 weeks inspiratory muscle training-IMT (50% of the maximum inspiratory pressure); group II-athletes performing standard swimming training with 8 weeks inspiratory muscle training (15% MIP). The following tests were performed three times: MIP, MEP, Borg RPE scale and swimming test: T-30 test; 8 × 100 progressive test. Results: There was a significant increase in the MIP and MEP in group I after IMT. There was a significant increase in the distance swam during the T-30 only in group I after IMT. Significant differences were found between the first and third measurements in group I, and the effect was maintained at follow-up. There was also a significant reduction in La concentration in group I after IMT. There was a significant reduction in heart rate at 88% and 93% of the maximum speed in group I after the applied training. Conclusion: Inspiratory muscle training with 50% of the maximum inspiratory pressure load significantly increased the respiratory muscle strength of disabled swimmers. The application of higher-intensity IMT effectively improved the training level and physiological parameters of the swimmers' effort, indicating the need to include this type of training in the standard preparation of disabled swimmers.

Comparative Study of Different Respiratory Muscle Training Methods: Effects on Cardiopulmonary Indices and Athletic Performance in Elite Short-Track Speedskaters.

Respiratory muscle training (RMT) improves endurance performance, balance, and ability to repeat high-intensity exercise bouts, providing a rationale to be applied in short-track speedskating. To establish a preferable RMT method for short-track speedskating, the influence of inspiratory pressure threshold loading (IPTL) and voluntary isocapnic hyperpnoea (VIH) on cardiopulmonary indices and athletic performance was investigated. Sixteen elite short-track speedskaters completed 6 weeks of RMT based on IPTL or VIH. Wingate Anaerobic Tests (WAnTs), cardiopulmonary exercise tests (CPETs), spirometry assessments, and on-ice time trials were performed before and after RMT intervention. Repeated measures ANOVA was used to assess the differences between each method's influence. No statistically significant (p > 0.05) differences between RMT methods were found in performance during the WAnT, CPET, or specific on-ice time trials. Spirometry measures were similar between both methods. Significant effects were found for the interaction between maximum breathing frequency during CPET (BFmax) and method (p = 0.009), as well as for the interaction between BFMax, method, and sex (p = 0.040). BFmax decreased for IPTL and increased for VIH. The interaction between method and sex revealed that BFmax increased only in males performing VIH. Our findings suggest that IPTL and VIH lead to analogous effects in the study participants, highlighting a negligible practical disparity in the impact of different RMT methods in elite short-track speedskaters.

Critical Analysis of Information Provided by ChatGPT on Lactate, Exercise, Fatigue, and Muscle Pain: Current Insights and Future Prospects for Enhancement.

This study aimed to critically evaluate the information provided by ChatGPT on the role of lactate in fatigue and muscle pain during physical exercise. We inserted the prompt: "What is the cause of fatigue and pain during exercise?" using ChatGPT versions 3.5 and 4o. In both versions, ChatGPT associated muscle fatigue with glycogen depletion and "lactic acid" accumulation, while pain was linked to processes such as inflammation and microtrauma. We deepened the investigation with ChatGPT 3.5, implementing user feedback to question the accuracy of the information about lactate. The response was then reformulated, involving a scientific debate about the true role of lactate in physical exercise and debunking the idea that it is the primary cause of muscle fatigue and pain. We also utilized the creation of a "well-crafted prompt", which included persona identification and thematic characterization, resulting in much more accurate information in both the ChatGPT 3.5 and 4o models, presenting a range of information from the physiological process of lactate to its true role in physical exercise. The results indicated that the accuracy of the responses provided by ChatGPT can vary depending on the data available in its database and, more importantly, on how the question is formulated. Therefore, it is indispensable that educators guide their students in the processes of managing the AI tool to mitigate risks of misinformation.

Exerting force at the maximal speed drives the increase in power output in elite athletes after 4 weeks of resistance training.

PURPOSE: In the present study, we examined how a 4-week intervention of maximal intended velocity (MIVRT) and controlled velocity resistance training (CRT)-induced task-specific responses in expert individuals. METHODS: Twenty elite athletes were randomly assigned to either a MIVRT (n = 10) or CRT (n = 10) group, both following the same volume-load training based on the back-squat three times a week but with different intentions in moving load (force-exertion speed). We assessed one-repetition maximum (1RM), mean propulsive velocity (MPV), and mean propulsive power (MPP) using a progressive-loading test before and after the intervention. A linear position transducer was used to monitor propulsive velocity in training and testing sessions. RESULTS: Both groups significantly increased their 1RM (CRT: + 12.3%, p < 0.001, d = 0.39; MIVRT: + 12.5%, p < 0.001, d = 0.45). Only the MIVRT group showed a significant improvement in MPV (p < 0.01) across different stepping loads, while both groups improved in MPP (MIVRT: + 22.4%, p < 0.001, d = 0.54; CRT: + 8.1%, p = 0.04, d = 0.17). CONCLUSIONS: MIVRT induced significant adaptations in MPV and MPP at various loads (%1RM), underlining its specificity in targeting these parameters. Despite similar enhancements in 1RM, the distinct training protocols suggest that strength gains may stem from either maximal intent in moving loads or longer times under tension. This study highlights the role of execution speed in optimizing power outcomes, emphasizing task specificity as paramount to elicit physiological adaptations in chronically strength-trained individuals.

The acute effect of respiratory muscle training on cortisol, testosterone, and testosterone-to-cortisol ratio in well-trained triathletes - exploratory study.

The study investigated acute changes in cortisol (C) and testosterone (T) associated with a popular RMT method, voluntary isocapnic hyperpnoea (VIH), in well-trained triathletes. 19 athletes (7 females, 12 males) performed a VIH training session with pre- and post- serum C and T measurements. Repeated measures ANOVA was employed to analyze hormone changes during VIH, with additional time-sex interaction. Pearson correlation coefficient has been computed to identify the relationship between hormonal changes and age, anthropometric indices, respiratory muscle strength, and training experience. There was a statistically significant effect for C changes (F = 13.101, p = 0.002, ηp2 = 0.421, ω2 = 0.08). The C concentration was significantly lower after VIH (Mean Difference = -32.49 ± 39.13 nmol*L-1). No significant effects for T, T/C ratio, and time-sex interactions were observed (p > 0.05). Amongst many, significant correlations between the percentage of body fat and changes in C (r=-0.464, p=0.045), body mass and changes in T (r=0.516, p=0.024), height and changes in T (r=0.509, p=0.026) were found. VIH significantly lowered C concentration. No significant effects for T, T/C ratio, and no between-sex differences were observed. Noteworthy individual variability was observed in all the monitored indices. Significant correlations were found between acute hormone changes associated with VIH and selected anthropometric indices. The study provides initial insight into VIH's role in athletes' hormonal balance to possibly guide exercise prescription, autoregulation, arousal state management, and recovery practices in athletes.

Novel techniques for quantifying oxygen pulse curve characteristics during cardiopulmonary exercise testing in tetralogy of fallot.

Background: Cardiopulmonary exercise testing (CPET) is used in evaluation of repaired tetralogy of Fallot (rTOF), particularly for pulmonary valve replacement need. Oxygen pulse (O2P) is the CPET surrogate for stroke volume and peripheral oxygen extraction. Objectives: This study assessed O2P curve properties against non-invasive cardiac output monitoring (NICOM) and clinical testing. Methods: This cross-sectional study included 44 rTOF patients and 10 controls. Three new evaluations for O2P curve analysis during CPET were developed. Best fit early and late regression slopes of the O2P curve were used to calculate: 1) the early to late ratio, or "O2 pulse response ratio" (O2PRR); 2) the portion of exercise until slope inflection, or "flattening fraction" (FF); 3) the area under the O2P response curve, or "O2P curve area". Results: rTOF patients (median age 35.2 (27.6-39.4); 61% female) had a lower VO2 max (23.4 vs 45.6 ml/kg/min; p < 0.001) and O2P max (11.5 vs 19.1 ml/beat; p < 0.001) compared to controls. Those with a FF occurring <50% through exercise had a lower peak cardiac index and stroke volume, but not VO2 max, compared to those >50%. FF and O2P curve area significantly correlated with peak cardiac index, stroke volume, left and right ventricular ejection fraction, and right ventricular systolic pressure. Conclusion: CPET remains an integral part in the evaluation of rTOF. We introduce three non-invasive methods to assess exercise hemodynamics using the O2P curve data. These evaluations demonstrated significant correlations with stroke volume, cardiac output, and right ventricular pressure.

Acute Cardiovascular Responses to the 100-Mile Western States Endurance Run.

Ultramarathon participation is growing in popularity and exposes runners to unique stressors including extreme temperatures, high altitude, and exceedingly long exercise duration. However, the acute effects of ultramarathon participation on the cardiovascular system are not well understood. PURPOSE: To determine the acute effects of trail ultramarathon participation on central artery stiffness and hemodynamics. METHODS: Forty-one participants (9F, 32M) participating in the 2023 Western States Endurance Run underwent measures of carotid-femoral pulse wave velocity (cf-PWV) and pulse wave analysis pre- and <1h post-race. Subendocardial viability ratio (SEVR) was calculated from central blood pressure (BP) waveforms. Serum was analyzed for creatine kinase (CK) activity as a measure of muscle damage. Normally distributed data are presented as mean±SD and non-normally distributed data are presented as median (interquartile range). RESULTS: Runners were middle-aged and generally lean (age=44±9 y, BMI=22.7±1.8 kg●m-2). There was no difference in cf-PWV from pre- to post-race (pre=6.4±1.0, post=6.2±0.85 m/s, p=0.104), a finding that persisted after adjusting for mean arterial pressure (p=0.563). Systolic and diastolic BP were lower post-race (pre=129/77±9/7, post=122/74±10/8 mmHg, ps<0.001). Augmentation index (AIx; pre=17.3±12.2, post=6.0±13.7%, p<0.001), AIx normalized to a heart rate of 75bpm (p=0.043), reflection magnitude (pre=55.5(49.0-60.8), post=45.5(41.8-48.8) %, p<0.001), and SEVR (pre=173.0(158.0-190.0), post=127.5(116.5-145.8) %, p<0.001) were reduced post-race. CK increased markedly from pre- to post-race (pre=111(85-162), post=11,973(5,049-17,954) U/L, p<0.001). CONCLUSIONS: Completing a 161-km trail ultramarathon does not affect central arterial stiffness and acutely reduces BP despite eliciting profound muscle damage. However, the reduced post-race SEVR suggests a short-term mismatch between myocardial work and coronary artery perfusion.

Oxygen Consumption, Ventilatory Thresholds, and Work Zones in Nordic Walking Competitors.

Background: Nordic walking (NW) is a physical sports activity that has been sufficiently studied from the point of view of health, but physiological and performance analyses have not been so much. Objectives: With this study, we intend to analyse the physical work areas, according to ventilatory thresholds, that occur during a NW competition. Methods: Four participants of different characteristics anthropometrics (weight 57.6-85.6 kg; height 165.8-178 cm; and fat percentage 14.5-21.5%) gender (3 males and 1 female) and age (15-57 years) who participated in the NW regional championship have been chosen, and their electrocardiographic tracing was recorded using a NUUBO® device throughout the race, obtaining average and maximum heart rates (HR) in eight sections of the circuit. Previously, in the laboratory, a maximal stress test was performed to determine the maximum oxygen consumption (VO2max), the first (VT1) and second (VT2) ventilatory threshold (VT). With these data, four work areas were obtained. Results: Most of the sections of the circuit were conducted with average HRs in zone 2a (above average between VT1 and VT2 but below VT2) and peak HRs in zone 3 (between VT2 and VO2max). Conclusions: We conclude that, with the data collected on HR, VO2max, and VT, the training zones obtained can be related to the heart rates in the different sections of the circuit. This can be used to improve the sports performance of the walkers.

The clockwork of champions: Influence of circadian biology on exercise performance.

Exercise physiology and circadian biology are distinct and long-standing fields. Recently they have seen increased integration, largely due to the discovery of the molecular components of the circadian clock and recognition of human exercise performance differences over time-of-day. Circadian clocks, ubiquitous in cells, regulate a daily tissue specific program of gene expression that contribute to temporal patterns of physiological functions over a 24-h cycle. Understanding how circadian clock function in skeletal muscle, as well as other tissues contribute to exercise performance is still in the very early stages. This review provides background on this emerging field with a review of early exercise and time-of-day studies in both human and animals. We then move into the role of the circadian clock and its daily program of gene expression in skeletal muscle with a focus on specific metabolic and physiological outputs that vary over time-of-day. Lastly, we discuss the recognition that the timing of exercise communicates with the skeletal muscle circadian clock to adjust its phase settings and why this maybe important for performance and health.

The Diamond Framework for Team-based Active Learning for Physiology Courses.

Benjamin Bloom published his Taxonomy of Educational Objectives in 1956 [1] to help educators develop learning objectives for teaching. Since then, several modifications have been made to adapt Bloom's taxonomy to various uses and disciplines [2-4]. Introduction of the idea: As social constructivist educators, the authors of this article felt the need to adjust Bloom's taxonomy to match the unique characteristics of team-based learning (TBL) in physiology courses. Outcomes: Here, we are introducing the use of TBL for teaching physiology in undergraduate physiology courses that could be easily translated into other disciplines. Additionally, we are introducing the Diamond Framework for TBL, a modified Bloom's taxonomy to guide the writing of measurable learning outcomes and create assignments to help students apply their new knowledge and skills.

Exploring sex differences in blood-based biomarkers following exhaustive exercise using bioinformatics analysis.

This study examined the acute effects of exercise testing on immunology markers, established blood-based biomarkers, and questionnaires in endurance athletes, with a focus on biological sex differences. Twenty-four healthy endurance-trained participants (16 men, age: 29.2± 7.6 years, maximal oxygen uptake ( V ˙ O 2 max ): 59.4 ± 7.5 ml · min-1 · kg-1; 8 women, age: 26.8 ± 6.1 years, V ˙ O 2 max : 52.9 ± 3.1 ml · min-1 · kg-1) completed an incremental submaximal exercise test and a ramp test. The study employed exploratory bioinformatics analysis: mixed ANOVA, k-means clustering, and uniform manifold approximation and projection, to assess the effects of exhaustive exercise on biomarkers and questionnaires. Significant increases in biomarkers (lymphocytes, platelets, procalcitonin, hemoglobin, hematocrit, red blood cells, cell-free DNA (cfDNA)) and fatigue were observed post-exercise. Furthermore, differences pre- to post-exercise were observed in cytokines, cfDNA, and other blood biomarkers between male and female participants. Three distinct groups of athletes with differing proportions of females (Cluster 1: 100% female, Cluster 2: 85% male, Cluster 3: 37.5% female and 65.5% male) were identified with k-means clustering. Specific biomarkers (e.g., interleukin-2 (IL-2), IL-10, and IL-13, as well as cfDNA) served as primary markers for each cluster, potentially informing individualized exercise responses. In conclusion, our study identified exercise-sensitive biomarkers and provides valuable insights into the relationships between biological sex and biomarker responses.

A Descriptive Exploration of Heart Rate Response to Live Professional Irish Dance Performance.

Introduction: Research investigating the physiological demands of dance performance has documented exercise intensity and time spent in work and rest; however, available data are across limited dance genres and often use rehearsal or simulated conditions. Real-time data recorded during live performance with an audience are limited. The aim of the study is to provide a detailed description of the physiological demands of live professional Irish dance performance. Method: The entire Irish dance cast of Riverdance participated in the study (n = 24). Approval was granted by the Institutional Research Ethics Committee. Matinee and evening performances on the first day of a tour were examined in a descriptive, cross-sectional design. Heart rate (HR) monitors worn discretely under costumes recorded data every 5-seconds. Video analysis allowed calculation of time spent in work and rest. All descriptive analyses were split by role (troupe/lead) and sex (male/female). Results: Dancers worked at hard/very hard intensities (mean > 72%, peak > 91% HRmax) for ~3 minutes at a time for 3-9 individual dance numbers. There was a high variation in overall demand experienced by individual dancers due to variation in both duration and intensity of on-stage time, dependent upon their role. Mean total on-stage time was 18.18 ± 5.82 minutes, 19.43 ± 5.80 minutes, 29.71 ± 0.62 minutes, 20.00 ± 0.00 minutes for male troupe, female troupe, male lead, and female lead dancers, respectively. Recovery periods were varied in terms of duration, activity undertaken, and HR response. Conclusion: Individual dance numbers within a professional Irish dance show were high intensity for a short duration when considered in isolation, but overall physiological demand experienced by any one dancer across the entire show varied dependent upon their role and off-stage/recovery practices. Future research investigating the physiological demands of dance performance should ensure analysis accounts for the individual dancer's role and should capture the entire show duration in repeated exposures.

Muscle-derived microRNAs correlated with thigh lean mass gains during progressive resistance training in older adults.

Resistance training (RT) remains the most effective treatment for age-related declines in muscle mass. However, many older adults experience attenuated muscle hypertrophy in response to RT when compared with younger adults. This may be attributed to underlying molecular processes that are dysregulated by aging and exacerbated by improperly prescribed RT weekly volume, intensity, and/or frequency doses. MicroRNAs (miRNAs) are key epigenetic regulators that impact signaling pathways and protein expression within cells, are dynamic and responsive to exercise stimuli, and are often dysregulated in diseases. In this study, we used untargeted miRNA-seq to examine miRNA in skeletal muscle and serum-derived exosomes of older adults (n = 18, 11 M/7 F, 66 ± 1 yr) who underwent three times per wk RT for 30 wk [e.g., high intensity three times/wk (HHH, n = 9) or alternating high-low-high (HLH) intensity (n = 9)], after a standardized 4-wk washin. Within each tissue, miRNAs were clustered into modules based on pairwise correlation using weighted gene correlation network analysis (WGCNA). Modules were tested for association with the magnitude of RT-induced thigh lean mass (TLM) change [as measured by dual-energy X-ray absorptiometry (DXA)]. Although no modules were unique to training dose, we identified miRNA modules in skeletal muscle associated with TLM gains irrespective of exercise dose. Using miRNA-target interactions, we analyzed key miRNAs in significant modules for their potential regulatory involvement in biological pathways. Findings point toward potential miRNAs that may be informative biomarkers and could also be evaluated as potential therapeutic targets as an adjuvant to RT to maximize skeletal muscle mass accrual in older adults.NEW & NOTEWORTHY In this work, we identified a set of microRNAs correlated with thigh lean mass gains in a group of older adults. To our knowledge, this is the first time these microRNAs have been identified as novel predictive biomarkers correlating with lean mass gains in aging adults. As biomarkers, these may help interventionalists identify older individuals that are positively responding to an exercise intervention.