VO2max Research Articles

The Effects of Physical Activity and the Consequences of Physical Inactivity in Adult Patients with Congenital Heart Disease During the COVID-19 Pandemic.

The ongoing COVID-19 pandemic has infected more than 500 million people worldwide. Several measures have been taken to reduce the spread of the virus and the saturation of intensive care units: among them, a lockdown (LD) was declared in Italy on 9 March 2020. As a result, gyms, public parks, sports fields, outdoor play areas, schools, and multiple commercial activities have been closed. The consequences of physical inactivity can be dramatic in adult patients with congenital heart disease (ACHD), in which the benefit of regular exercise is well known. In this study, we investigated the effects of reduced physical activity during the COVID-19 pandemic on ACHD's exercise capacity. Patients who performed exercise or cardiopulmonary exercise tests from October 2019 to February 2020 and one year after lockdown with the same protocol were retrospectively enrolled in our database. ACHD patients aged ≥ 18 years old under regular follow-up. significant clinical and/or therapeutic changes between the two tests; significant illness occurred between the two tests, including COVID-19 infection; interruption of one of the tests for reasons other than muscle exhaustion. Thirty-eight patients (55.6% males) met the inclusion criteria. Before the lockdown, 17 patients (group A) were engaged in regular physical activity (RPA), and 20 patients (group B) had a sedentary lifestyle. After LD, in group A, (a) the weekly amount of physical activity reduced with statistical significance from 115 ± 46 min/week to 91 ± 64 min/week (-21%, p = 0.03); (b) the BMI did not change; (c) the duration of exercise test and VO2 max at cardiopulmonary exercise test showed a significant reduction after the LD. In group B, BMI and exercise parameters did not show any difference. The COVID-19 pandemic dramatically changed the habits of ACHD patients, significantly reducing their possibility to exercise. Our data analyzed in this extraordinary situation again demonstrated that physical inactivity in ACHD worsens functional capacity, as highlighted by VO2 max. Regular exercise should be encouraged in ACHD patients to preserve functional capacity.

Discrepancy in the Diagnosis of Heart Failure With Preserved Ejection Fraction Between Supine Versus Upright Exercise Hemodynamic Testing.

Invasive exercise right heart catheterization is a gold standard in diagnosing heart failure with preserved ejection fraction (HFpEF). Body positions during the test influence hemodynamics. However, the discrepancy in HFpEF diagnosis between exercise testing in supine versus upright position is unknown. We conducted a 2-center prospective study enrolling patients referred for exercise right heart catheterization for HFpEF. We performed a Supright protocol integrating submaximal supine bicycle ergometry (20 W) followed by maximal upright bicycle ergometry with a breath-by-breath oxygen analyzer. HFpEF hemodynamic criteria specific to testing positions were applied. Patients were considered to have concordant HFpEF if they met criteria in both positions or discordant HFpEF if they met criteria only in the supine position. Of 36 patients who met HFpEF criteria in supine position, 18 (50%) did not meet criteria in upright position (discordant HFpEF). Discordant HFpEF had less atrial fibrillation (0% versus 55%; P<0.001), lower left atrial volume (60±14 versus 77±21 mL; P=0.010), and lower H2FPEF score (2.1±1.3 versus 5.1±2.3; P<0.001). In supine position, pulmonary arterial wedge pressure was lower in discordant HFpEF at rest (15±4 versus 19±7 mm Hg; P=0.040). In upright position, pulmonary arterial wedge pressure was lower in discordant HFpEF both at rest (8±4 versus 14±6 mm Hg; P=0.002) and at peak exercise (14±4 versus 27±7 mm Hg; P<0.001). Pulmonary arterial wedge pressure/cardiac output slope was lower in discordant HFpEF (1.6±1.7 versus 3.6±2.9; P<0.001). Maximal workload (46±18 versus 49±24 W; P=0.59) or peak oxygen consumption (11.4±2.8 versus 12.9±3.4 mL/[kg·min]; P=0.15) was similar between groups. Half of patients who met HFpEF criteria in the supine position did not meet the criteria in the upright position. Patients with a discordant HFpEF phenotype had less structural and hemodynamic abnormalities compared with those with concordant HFpEF. A Supright exercise right heart catheterization approach is feasible and merits further investigation to determine the clinical implications of discordant exercise hemodynamic findings in supine and upright positions.

Effect of double rocking jump rope training on lower limb muscle strength of badminton players.

Double rocking jump rope training can effectively enhance physical recovery, adaptability to exercise load, and lower limb muscle strength of badminton players in sports colleges, thus offering valuable insights for improving training methods in sports colleges and universities. To investigate the effect of double rocking jump rope training on the lower limb muscle strength of badminton players specializing in badminton in sports colleges. An experimental study was conducted through a ten-week teaching intervention experiment with badminton players. Relevant heart rate indexes and badminton related lower limb muscle strength indexes were measured before and after the experiment. The data of the measured relevant indexes were statistically and analytically analyzed. At the end of the experiment, the physical recovery level and the heart's adaptability to the exercise load of the control group were improved, and the lower limb muscle strength test indexes and sports performance were better than before the experiment. In the experimental group, badminton players' physical function, anaerobic metabolism of the body and other aspects also improved. The physical function of the experimental group of badminton players, the energy supply capacity of the body anaerobic metabolism and aerobic work capacity all have an enhancement effect, enabling badminton players to adapt to large exercise loads quickly and improve the recovery rate of physical fitness. The introduction of double rocking jump rope into badminton training classes in sports colleges and universities as a means of lower limb muscle strength training is conducive to improving the level of lower limb muscle strength of special badminton players, enriching the teaching and training means of lower limb muscle strength in sports colleges and universities, and broadening the research field of lower limb muscle strength in badminton in sports colleges and universities.

Differences in 5-km running pace between female and male triathletes.

During an IRONMAN, the pacing strategy in the running segment differs significantly between sexes. However, it is unknown if sex affects the running pace in shorter triathlon events. This study compared the pacing strategy between sexes during a 5-km running test performed following a 20-km cycle (sprint triathlon distances). Participants included 16 men (34.7±7.5 years) and 16 women (39.5±7.7 years). A cardiopulmonary exercise test to measure maximal oxygen uptake (˙VO2max) and a functional threshold power (FTP) were performed. Body composition was measured using a dual-emission X-ray absorptiometry system. Participants cycled at 90% FTP for 20 km and ran as fast as possible for 5 km. The total time spent cycling 20 km was shorter (~11%) in male than in female athletes (p<0.001). Similarly, the time spent to run 5 km was shorter in male (~11%) than in female athletes (p=0.006). Male athletes performed the last 600 m of the 5km race significantly faster than the initial meters (p<0.05). Female athletes performed the 5-km race without pace variation (p>0.05). In conclusion, apart from the sex differences associated with performance in short-term triathlon events, the pacing strategy was also different.

Mitochondrial dynamics and bioenergetics in Alzheimer's induced pluripotent stem cell-derived neurons.

Mitochondrial (MT) dysfunction is a hallmark of Alzheimer's Disease (AD), but the scope and severity of these specific deficits across forms of AD are not well characterized. We designed a high-throughput, longitudinal, phenotypic assay to track MT dynamics and bioenergetics in glutamatergic iPSC-derived human neurons possessing mutations in presenilin 1 (PSEN1), presenilin 2 (PSEN2) and the amyloid beta precursor protein (APP). Each gene set was comprised of iPSC-derived neurons from an AD patient as well as two to three engineered mutations with appropriate isogenic and age matched controls. These iPSC-derived neurons were imaged every other day beginning at DIV10 to assess how MT length and content change over a ten day time course using a mitochondrially targeted reporter. A second cytosolic reporter allowed for visualization of neurites. Bioenergetics assays, focusing on MT respiration and individual electron transport chain (ETC) complexes, were also surveyed over this time course. Mutations in all three genes altered MT function measured by basal, ATP-linked, and maximal oxygen consumption rate; and spare respiratory capacity, with PSEN1/PSEN2 alleles being more severe than APP mutations. Electron flow through Complexes I-IV was decreased in PSEN1/PSEN2 mutations but; in contrast, APP alleles had only modest impairments of Complexes I and II. We measured aspects of MT dynamics, including fragmentation, and neurite degeneration, both of which were dramatic in PSEN1/PSEN2 alleles, but essentially absent in APP alleles. The marked differences in MT pathology may occur from the distinct ways amyloids are processed into amyloid beta peptides (Aβ) and may correlate with the disease severity.

Acute change in resting energy expenditure and vital signs in response to white tea consumption in females: a pilot study

BackgroundWhite tea, derived from the Camellia sinensis plant like other teas, uses tender buds and young leaves and undergoes minimal processing. This results in higher levels of antioxidants and bioactive substances, which may enhance thermogenesis more effectively than other teas. This first human study aimed to investigate the acute effects of white tea consumption on resting energy expenditure (REE) and some vital signs, including blood pressure (BP), heart rate (HR), and body temperature (BT).MethodsThirty-two healthy female volunteers with normal initial BP and whose caffeine intakes were < 300 mg/d were enrolled in the study. The caffeine and total phenolic content of white tea samples were determined by the high-performance liquid chromatography method and the Folin-Ciocalteu colorimetric method, respectively. After baseline measurements, participants consumed white tea containing 6 mg of caffeine per kilogram of lean body mass, and the white tea was prepared with bottled drinking water at 80 °C and brewed for 3 min. REE, BP, and BT were assessed at various intervals (baseline, 30 min, 120 min, and 180 min) post-consumption of the white tea.ResultsThe results revealed a significant increase in REE by 8.7% at 180 min after the consumption. In particular, there was a substantial difference in both values between the intervals of 30 min to 180 min and baseline to 180 min for REE (p < 0.05). Maximal oxygen consumption and BT also increased significantly over time (p < 0.05) and the observed increment in BT suggests a thermogenic effect associated with white tea consumption. However, systolic BP, diastolic BP, and heart rate showed no significant difference.ConclusionsThese findings suggest white tea consumption may acutely enhance REE and maximal oxygen consumption, so the results are promising for body weight management. This study is the first human study in the literature about the effects of white tea on energy expenditure and vital signs.

Associations of Cardiovascular Health Metrics in Childhood and Adolescence With Arterial Health Indicators in Adolescence: The PANIC Study.

Our aim was to assess the relationships of cardiovascular health metrics, cardiorespiratory fitness, lean mass, and fat percentage with arterial structure and function from childhood to adolescence. Five hundred four children aged 6 to 9 years were examined in the PANIC (Physical Activity and Nutrition in Children) study at baseline, 2 and 8 years later. The associations of adjusted American Heart Association cardiovascular health metrics (smoking status, body mass index-SD score, moderate-to-vigorous physical activity, diet quality, plasma total cholesterol, systolic blood pressure, plasma glucose categorized into poor, intermediate, and ideal), the American Heart Association cardiovascular health score, cardiorespiratory fitness measured by maximal oxygen uptake in a bicycle exercise test, lean mass and fat percentage with carotid intima-media thickness (cIMT) and pulse wave velocity (PWV) were analyzed cross-sectionally and longitudinally in 277 participants at age 15 to 17 years. Higher American Heart Association cardiovascular health score at baseline was associated with lower PWV at 8-year follow-up (ß, -0.19 [95% CI, -0.32 to -0.05]). Higher body mass index-SD score and systolic blood pressure were associated with higher cIMT (ß, 0.18 [95% CI, 0.05-0.31]); and (ß, 0.13 [95% CI, 0.00-0.25]; respectively) and PWV (ß, 0.20 [95% CI, 0.07-0.34]) and (ß, 0.13 [95% CI, 0.00-0.26]; respectively) at 8-year follow-up. Higher moderate-to-vigorous physical activity was associated with higher cIMT (ß, 0.25 [95% CI, 0.07-0.43]); yet lower PWV (ß, -0.25 [95% CI, -0.44 to -0.06]) at 8-year follow-up. Better cardiorespiratory fitness (ß, 0.29 [95% CI, 0.08-0.51]) and higher lean mass (ß, 0.51 [95% CI, 0.03-0.98]) were associated with higher cIMT after accounting for American Heart Association cardiovascular health score at 8-year follow-up. While our results suggest that higher cardiometabolic risk factors in childhood may exert unfavorable effects on arterial health during adolescence, we demonstrated the complexity of relationships between cardiovascular health metrics and arterial health indicators in childhood and adolescence. We found different associations of cardiovascular health metrics with cIMT and PWV in childhood and adolescence, calling for caution when interpreting the results of various cardiovascular risk factors with measures of arterial health, particularly in youth. URL: https://www.clinicaltrials.gov; Unique identifier: NCT01803776.

The Role of Digital Smart Wearable Technology in VO2MAX Measurement to Support Athlete Performance and Public Health

This study employed the systematic literature review to investigate to what extent digital smart wearable technology was used in measuring VO2MAX to support athlete performance and public health. To achieve the goal, data were obtained from articles searched through Google Scholar. The search was conducted in September 2024 using the following keywords: (Smart Wearable OR Wearable Technology AND VO2MAX OR VO2 Max OR Cardiorespiratory Fitness AND Athlete Performance OR Sports Performance OR Athletic Performance AND Public Health OR General Population OR Health Monitoring). The articles were selected by considering predetermined inclusion and exclusion criteria. For example, to be included in this review, the articles should be published in Scopus-indexed journals. Additionally, the publication period should be from 2019 to 2024. Based on this timeframe, 1,110 articles were found. Furthermore, they were screened again in multiple stages, and 16 articles that fit the theme and met the inclusion requirements were selected. During the article selection, this study followed the PRISMA guidelines. The results confirmed that wearable technology played an important role in athlete performance optimization through real-time monitoring of VO2MAX. The device enables exercise adjustments based on metrics such as heart rate and diurnal variations, which can improve exercise effectiveness and reduce the risk of injury. Interestingly, it also contributes significantly to improving public health by promoting active lifestyles, monitoring health parameters, and supporting self-health management, especially for the elderly and individuals with chronic diseases. Nonetheless, technical challenges, such as measurement accuracy, data synchronization issues, and user education needs, must be addressed for wearables to be optimally utilized. With proper development, wearable technology has great potential to improve athlete performance and public health. Keywords: Role, Digital Technology, Smart Wearable, VO2MAX, Athlete Performance, Public Health

Effect of Glycated Haemoglobin (HBA1c) on Cardiorespiratory Fitness (CRF) in a Population with Type 2 Diabetes Mellitus (T2DM): A Cross-Sectional Study.

Background and Objective: The aim of this study was to evaluate cardiorespiratory fitness (CRF) measures, maximal oxygen consumption (VO2 max), and minute ventilation/carbon dioxide production (VE/VCO2 slope and others) among the T2DM population based on glycated haemoglobin (HBA1c). Material and Methods: The present study comprised a cross-sectional design, with two groups, based on HbA1c values (≤7 and ≥7.1). Laboratory samples were taken to evaluate glycated haemoglobin and fasting blood glucose (FBS). Cardiopulmonary exercise testing was performed to calculate various fitness-related parameters. Data analysis: An independent t-test was used to analyse the outcomes in the two groups. p < 0.05 was considered significant. Linear regression was used to examine the influence of predictor variables on dependent variables. Results: A total of 70 patients agreed to participate in the study, with 19 females and 51 males. The mean (standard deviation) BMI (body mass index) of all participants was 29.7(5.2), the mean (SD) weight was 84.4 (18.9) kg, and the mean height was 167.4 (23) cm. The average age of the individuals was 52 ± 8 years. The independent t-test revealed a significant difference between the two groups in terms of CRF measures. Conclusions: The current research identified the presence of poor glycaemic control and cardiorespiratory fitness measures among the Brazilian population with T2DM. HBA1c, duration of diabetes, age, and BMI can be employed to predict the ventilatory threshold (VT) and VO2 max.

PROSPECTIVE ASSOCIATIONS OF PHYSICAL ACTIVITY AND SEDENTARY TIME IN ADOLESCENCE WITH CARDIOMETABOLIC RISK IN YOUNG ADULTHOOD.

Purpose: The relationship between sedentary time, physical activity, and cardiometabolic risk factors during the transition from adolescence to adulthood remain uncertain. We examined the prospective associations of sedentary time and physical activity at age 15 with cardiometabolic risk markers at age 24.Methods: We used data from the Physical Activity among Norwegian Children Studies (PANCS). Sedentary time, moderate-to-vigorous physical activity (MVPA), and vigorous physical activity (VPA) were measured by accelerometry. Outcomes included body mass index (BMI), waist circumference, visceral fat, maximal oxygen uptake (VO2max), systolic blood pressure, LDL-cholesterol, insulin, high-sensitivity CRP, and a clustered risk Z-score. The prospective associations were modelled through regression.Results: A total of 731 boys and girls participated at age 9 (2005-2006) and 15 (2011-2012), and 258 of these participated again at age 24 (2019-2021). Multiple imputation was performed for all eligible individuals (n = 708). Each standard deviation increase (min/day) in sedentary time at age 15 was associated with lower VO2max at age 24 (β: -1.6 ml/kg/min; 95%CI: -2.8, -0.5). Each standard deviation increase (min/d) in MVPA (β: 1.6 ml/kg/min; 95%CI: 0.8, 2.4) and VPA (β: 1.6 ml/kg/min; 95%CI: 0.8, 2.4) at age 15 were associated with higher VO2max at age 24. VPA in adolescence was further inversely associated with visceral fat mass (β: -41 g; 95%CI: -78, -3), insulin level (β: -4.3 pmol/L; 95%CI: -8.2, -0.4), and the clustered risk Z-score (β: -0.09; 95%CI: -0.18, -0.01) in young adulthood. Childhood BMI modified the association of both MVPA and VPA with clustered risk, with the greatest magnitude of association observed in the highest BMI tertile.Conclusions: Physical activity, especially of vigorous intensity, during adolescence appear to beneficially affect cardiometabolic health in young adulthood. These health benefits may be most pronounced among overweight/obese youth.

Minute Ventilation/Carbon Dioxide Production Slope Could Predict Short- and Long-Term Prognosis of Patients After Acute Decompensated Heart Failure.

(1) Background: Heart failure (HF) leads to functional disability and major cardiovascular events (MACEs). Cardiopulmonary exercise testing (CPET) is the gold standard for assessing aerobic capacity and prognostic stratification. This study aimed to evaluate the predischarge CPET variables in patients with acute decompensated HF and identify the submaximal CPET variables with prognostic value. (2) Methods: A retrospective cohort study was conducted at a tertiary center in Taiwan. Patients surviving their first episode of decompensated HF and undergoing predischarge CPET (February 2017 to January 2023) were analyzed. Follow-up was conducted until a MACE or administrative censoring (up to 5 years). Cox regression identified the significant predictors of MACE. (3) Results: The study included 553, 485, and 267 patients at the 3-month, 1-year, and 5-year follow-ups, respectively. MACE rates were 15.0%, 34.2%, and 50.9%. The VE/VCO2 slope was a significant predictor of MACE at all intervals. A VE/VCO2 slope >38.95 increased the risk of MACE by 2.49-fold at 3 months and 1.81-fold at 1 year (both p < 0.001). A slope > 37.35 increased the 5-year MACE risk by 1.75-fold (p = 0.002). (4) Conclusions: The VE/VCO2 slope is a significant submaximal CPET predictor of MACE in patients post-acute decompensated HF for both short- and long-term outcomes.

Time Spent Near Maximal Oxygen Uptake During Exercise at Different Regions of the Severe-Intensity Domain.

Faricier, R, Fleitas-Paniagua, PR, Iannetta, D, Millet, GY, Keir, DA, and Murias, JM. Time spent near maximal oxygen uptake during exercise at different regions of the severe-intensity domain. J Strength Cond Res XX(X): 000-000, 2024-This study applied the critical power (CP) model and several bouts of constant-power exercise within different regions of the severe-intensity domain to determine whether there exists an optimal intensity to maximize time spent near V̇o2peak. Subjects visited the laboratory 9 times. After a ramp-incremental test to determine V̇o2peak and peak power output (POpeak), 9 active individuals (5 females) performed 4 constant-power bouts to task failure between 65 and 100%POpeak to estimate CP and total finite work above CP (W'). Subjects then completed 4 additional exhaustive trials predicted to result in task failure in ∼3, 6, 9, and 12 minutes. Time spent at V̇o2peak was calculated as the duration at which V̇o2 ≥ 95% of the trial-specific V̇o2peak. The level of significance set for the study was p < 0.05. Mean CP and W' were 201 ± 48 W and 17.6 ± 8.4 kJ, respectively. For each bout, time to task failure was 2.7 ± 0.5, 6.3 ± 0.6, 9.5 ± 1.2, and 13.1 ± 3.1 minutes for the 3-, 6-, 9-, and 12-minute conditions. Time spent at V̇o2peak during the 3-minute trial (45 ± 22 seconds) was shorter than during the 9-minute (204 ± 104 seconds; p = 0.002) and 12-minute trials (260 ± 155 seconds; p < 0.001). The 6-minute trial (117 ± 46 seconds) had shorter (p = 0.005) time spent at V̇o2peak compared with the 12-minute trial. At least when performing single bouts of exercise, intensities closer to CP (i.e., those sustainable for ∼9 minutes or longer) seem preferable compared with POs in the upper regions of the severe-intensity domain to maximize time at V̇o2peak.

Addressing mental health challenges in college students: A biomechanical approach to mitigating stress and cognitive load through physical intervention strategies

The main objective of this investigation is to find out how biomechanical actions, such as physical activity programs, balanced adjustments, and mindfulness-based posture correction, are successful at reducing Cognitive Load (CL) and levels of stress among college students. Mechanical adjustments decreased stress, physical activity reduced CL, and mindfulness-based posture correction improved Mental Health (MH), according to a long-term experiment with 28 students from four distinct educational fields. Investigators examined students’ stress, CL, and BH levels monthly. The outcome results dealt with all three predictions. A student’s Perceived Stress Scale (PSS) score dropped from 24.66 to 18.10 (mean difference = 6.56, t = 4.82, p = 0.0001) after experiencing practical changes, demonstrating a significant decrease in stress levels. Following the exercise support, CL, as determined by the NASA Task Load Index (NASA-TLX), dropped from 65.38 to 54.23 (mean difference = 11.15, t = 5.29, p = 0.00005). Ratings for BH increased significantly after exercising mindfulness-based posture correction (from 78.63 to 85.13; mean difference = −6.50, t = −4.92, p = 0.00007). The median variation in PF (VO2 Max) went from 40.46 to 45.11 (t = −3.78, p = 0.0012), and the difference in value was −4.65.

An Online Training Program Was Effective on Improving Physical Performance and Body Composition in U20 Soccer Players During the COVID-19 Quarantine

Abstract It is recommended for athletes keep training to reduce the negative effects of detraining. This study aimed to verify the effects of a 15-week online training intervention during a pandemic quarantine in body composition and physical capacity of highly trained soccer players. Sixteen male under-20 soccer players were assessed after the first period of COVID-19 quarantine (March 2020 to September 2020; 170 days), and after the second period of COVID-19 quarantine (November 2020 to February 2021, 107 days). Body composition, vertical jump height, hamstring maximum strength and aerobic capacity were assessed. The online training program was performed during the second lockdown. In comparison with first pre assessments, results showed that fat mass (−0.95 ± 1.27), free fat mass (1.22 ± 1.19), squat jump height (5.36 ± 1.99) and counter movement jump (3.19 ± 3.77) were significantly improved (P &lt; 0.05). However, there were no significant changes in total body mass, hamstring eccentric strength, and Yo-Yo IR1 after online training (P &gt; 0.05). In summary, the findings of this study highlight the importance of carrying out a training program during a period of absence from traditional soccer training, in order to maintain the level of physical capacities of youth soccer players.

Assessment and repeatability of aerobic capacity using the Chester Step Test among current, former, and never smokers.

Cigarette smoking contributes to reduced cardiorespiratory performance, which may improve upon cessation. Consequently, former smokers' cardiorespiratory fitness should not be significantly different from that of never-smokers. This study aims to compare V̇O2max values among current, former, and never smokers and assess the repeatability of measurements using the Chester Step Test (CST). V̇O2max measurements were available from a total of 70 subjects (23 current, 23 former, and 24 never-smokers) and showed significant repeatability. Current smokers had the worst aerobic capacity, with a mean VO2max ± SD of 38.8 ± 4.5, which was significantly lower than the VO2max of 41.62 ± 3.8 in never-smokers (p < 0.0001) and 41.43 ± 4.6 in former smokers (p < 0.0001). No significant differences were observed between never-smokers and former smokers. V̇O2max estimates by CST were reproducible and showed that the aerobic capacity of individuals who smoke is substantially inferior compared to never and former smokers. Improvement in cardiorespiratory performance following smoking cessation may have important implications for smoking cessation, especially for those smokers who perceive enhanced physical performance as a tangible benefit.

Effects of high-intensity intermittent cross-training on maximal oxygen uptake

We investigated the effects of high-intensity intermittent cross-training (HIICT) on maximal oxygen uptake (・VO2max). The HIICT consisted of alternating intermittent 20-s treadmill running (1st, 3rd, 5th, and 7th bouts) and 20-s bicycle exercise (2nd, 4th, and 6th bouts) with a 10-s rest period. Each intensity for running and bicycling of the HIICT corresponded to an oxygen demand of ∼160% and ∼170% of the O2max, respectively. Fifteen healthy young males (aged [24 ± 1] yrs) were randomly assigned to training (TG, n = 8) and non-training control (CG, n = 7) groups. The TG completed this HIICT daily 4 days/week for 6 weeks. Significant group × time interactions were observed for both the running and bicycling O2max (p < 0.001 each). After the training, the ・VO2max for both running ([57.4 ± 4.8] mL·kg−1·min−1) and bicycling ([50.6 ± 3.7] mL·kg−1·min−1) in the TG were significantly higher than those for running ( [50.1 ± 3.1] mL·kg−1·min−1) and bicycling ( [43.7 ± 3.6] mL·kg−1·min−1) in the CG, respectively (p < 0.01 each). Post-hoc tests revealed a significant increase in ・VO2max for running and bicycling in the TG after the HIICT (p < 0.001 each) but no significant difference in the CG. These results demonstrated that the newly developed HIICT increases the ・VO2max for both running and bicycling.

ВЛИЯНИЕ ДЛИТЕЛЬНОСТИ СТУПЕНИ В ТЕСТАХ С ВОЗРАСТАЮЩЕЙ НАГРУЗКОЙ НА ПОКАЗАТЕЛИ АЭРОБНЫХ ВОЗМОЖНОСТЕЙ СПОРТСМЕНОВ-ЛЮБИТЕЛЕЙ МОЛОДОГО И СРЕДНЕГО ВОЗРАСТА

The purpose of the research - to evaluate the influence of stage duration in the test with stepwise increasing load to failure on the aerobic capacity indices of amateur athletes. Materials and research methods. Endurance was assessed using Cyclus 2 bicycle ergometer, Cosmed K5 gas analyser and Biosen lactometer. Student's t-test was used to analyze differences between groups. Research results. Stage duration had a significant effect on power at the level of maximal oxygen consumption and power at the level of anaerobic exchange threshold, but had no significant effect on maximal oxygen consumption, heart rate at the level of on maximal oxygen consumption and anaerobic threshold. Conclusion. The study confirms that stage duration in the step test influences the assessment of aerobic capacity of young and middle-aged amateur athletes. Individual responses to stage duration changes were mixed, highlighting the need for a personalized approach in interpreting results.

Validating the Use of Continuous Glucose Monitors With Nondiabetic Recreational Runners.

Continuous glucose monitors (CGMs) are becoming increasingly popular among endurance athletes despite unconfirmed accuracy. We assessed the concurrent validity of the FreeStyle Libre 2 worn on 2 different sites at rest, during steady-state running, and postprandial. Thirteen nondiabetic, well-trained recreational runners (age = 40 [8]y, maximal aerobic oxygen consumption = 46.1 [6.4]mL·kg-1·min-1) wore a CGM on the upper arm and chest while treadmill running for 30, 60, and 90minutes at intensities corresponding to 50%, 60%, and 70% of maximal aerobic oxygen consumption, respectively. Glucose was measured by manually scanning CGMs and obtaining a finger-prick capillary blood glucose sample. Mean absolute relative difference, time in range, and continuous glucose Clarke error grid analysis were used to compare paired CGM and blood glucose readings. Across all intensities of steady-state running, we found a mean absolute relative difference of 13.8 (10.9) for the arm and 11.4 (9.0) for the chest. The coefficient of variation exceeded 70%. Approximately 47% of arm and 50% of chest paired glucose measurements had an absolute difference ≤10%. Continuous glucose Clarke error grid analysis indicated 99.8% (arm) and 99.6% (chest) CGM data fell in clinically acceptable zones A and B. Time-in-range analysis showed reduced accuracy at lower glucose levels. However, CGMs accurately detected trends in mean glucose readings over time. CGMs are not valid for point glucose monitoring but appear to be valid for monitoring glucose trends during steady-state exercise. Accuracy is similar for arm and chest. Further research is needed to determine whether CGMs can detect important events such as hypoglycemia during exercise.

Age- and Gender-Specific Reference Values for Physical Performance in Tunisian Youth Basketball Players.

Physical performance is becoming increasingly critical in basketball, as it directly influences players' agility, power, and endurance. This study aimed to assess the progression of body composition and physical performance metrics across different ages and genders, establishing age- and gender-specific reference values for Tunisian basketball athletes. A total of 469 Tunisian basketball players (239 boys and 230 girls) were assessed and grouped by age. Anthropometric measures-including standing and sitting height, body mass, leg length, body mass index, fat mass, fat-free mass, body fat percentage, wingspan, and leg muscle volume-were collected alongside physical performance metrics. Performance tests included countermovement and squat jumps, change-of-direction speed, maximal oxygen uptake, flexibility, the five-jump test, and 5 m, 10 m, and 20 m sprints with and without the ball. Normative data were generated based on age and gender categories. The findings revealed significant age-related improvements in both anthropometric and performance parameters. Boys consistently outperformed girls in physical and fitness-related measures, with gender differences becoming more pronounced with age. Stepwise regression analyses indicated that, for boys, body fat percentage, leg muscle volume, standing height, and wingspan were the best predictors of physical performance. For girls, body fat percentage, standing height, and sitting height were identified as key predictors. The newly established Tunisian reference values for physical performance in youth basketball provide valuable benchmarks that can support the development of explosive power and strength in players, aiding in talent identification and potentially enhancing individual and team performance outcomes.

Effects of variation in exercise training load on cognitive performances and neurotrophic biomarkers in patients with coronary artery disease.

This study compared the effects of linear (LP) and nonlinear (NLP) training periodization on cognitive functions, neurotrophic biomarkers [plasma brain-derived neurotrophic factor (BDNF), insulin-like growth factor-1 (IGF-1)], and cathepsin-B in patients with coronary artery disease (CAD). Forty-four patients with CAD reported to our laboratory on two occasions to undergo testing procedures before and after training sessions, and were then blindly randomized to NLP or LP for 36 training sessions. Visit 1 included blood samples and a maximal cardiopulmonary exercise testing to get maximal oxygen uptake (V̇o2peak). Visit 2 included cognitive functions assessment. Thirty-nine patients completed the study (LP: n = 20, NLP: n = 19), with no observed changes in cognitive performances after the training intervention in either group. IGF-1 concentration decreased in both groups (time-effect: P < 0.001), whereas BDNF concentration increased (time-effect: P < 0.05) without group interaction, and cathepsin-B did not change after the intervention. Associations were found between ΔV̇o2peak and ΔBDNF (R2 = 0.18, P = 0.04), and ΔIGF-1 and Δshort-term/working memory (R2 = 0.17, P = 0.01) in the pooled sample, with ΔIGF-1 and ΔBDNF accounting for 10% of the variance in Δshort-term/working memory. In the LP group, associations were found between ΔV̇o2peak and ΔBDNF (R2 = 0.45, P = 0.02), ΔBDNF and Δshort-term/working memory (R2 = 0.62, P = 0.004), ΔIGF-1 and Δshort-term/working memory (R2 = 0.31, P = 0.01), and ΔIGF-1 and Δexecutive function (R2 = 0.22, P = 0.04). This study indicates that linear and nonlinear training periodization led to an increase in BDNF, and a decrease in IGF-1, without change in cognitive function in individuals with stable CAD.NEW & NOTEWORTHY We used a novel and supervised iso-energetic training, integrating both moderate- and high-intensity aerobic exercises. Our findings indicate that greater variation in training load did not yield cognitive enhancements, although both protocols exhibited positive effects on brain-derived neurotrophic factor (BDNF) levels. Moreover, this study establishes a clear positive association between short-term and working memory and neurotrophic biomarkers. In addition, the independent predictive value of change in insulin-like growth factor-1 (IGF-1) on improvement in short-term and working memory highlight the close relationship between neurotrophic markers and cognition. Consequently, our results advocate for exercise training interventions targeting neurotrophic biomarkers to enhance cognitive function among individuals with coronary artery disease.