VO2max Research Articles

The validity of cardiopulmonary exercise testing for assessing aerobic capacity in neuromuscular diseases.

ObjectivesTo determine the content validity of cardiopulmonary exercise testing (CPET) for assessing peak oxygen uptake (VO2peak) in neuromuscular diseases (NMD). DesignBaseline assessment of a randomized controlled trial. SettingAcademic hospital. ParticipantsEighty-six adults (age: 58.0 ± 13.9 years) with Charcot-Marie-Tooth disease (n=35), post-polio syndrome (n=26), or other NMD (n=25). InterventionNot applicable. Main Outcome MeasuresWorkload, gas exchange variables, heart rate, and ratings of perceived exertion were measured during CPET on a cycle ergometer, supervised by an experienced trained assessor. Muscle strength of the knee extensors was assessed isometrically with a fixed dynamometer. Criteria for confirming maximal cardiorespiratory effort during CPET were established during 3 consensus meetings with an expert group. The percentage of participants meeting these criteria was assessed to quantify content validity. ResultsThe following criteria were established for maximal cardiorespiratory effort; a plateau in oxygen uptake (VO2plateau) as primary criterion, or 2 out of 3 secondary criteria; 1) peak respiratory exchange ratio (RERpeak) ≥1.10, 2), peak heart rate (HRpeak) ≥85% of predicted maximal heart rate, and 3) peak rating of perceived exertion (RPEpeak) ≥17 on the 6-20 Borg scale. These criteria were attained by 71 participants (83%). VO2plateau, RERpeak ≥1.10, HRpeak ≥85%, and RPEpeak ≥17 were attained by respectively 31%, 73%, 69%, and 72% of the participants. Peak workload, VO2peak, and knee extension muscle strength were significantly higher, and body mass index was lower (all p<0.05), in participants with maximal cardiorespiratory effort compared to other participants. ConclusionsMost people with NMD achieved maximal cardiorespiratory effort during CPET. Therewith, this study provides high quality evidence of sufficient content validity of VO2peak as a maximal aerobic capacity measure. Content validity may be lower in more severely affected people with lower physical fitness.

Effects of β-Alanine Supplementation on Subjects Performing High-Intensity Functional Training.

β-alanine, a non-essential amino acid found in the diet and produced through nucleotide catabolism, is significant for muscle performance due to its role in carnosine synthesis. This study aims to assess the impact of a 4-week β-alanine supplementation on neuromuscular fatigue in individuals engaging in High-Intensity Functional Training (HIFT) and its subsequent effect on sports performance, distinguishing between central fatigue from the CNS and peripheral fatigue from the muscular system. This study (a randomized controlled trial) comprised a total of 27 subjects, who were divided into two groups. Group A (the control group) was administered sucrose powder, while Group B (the experimental group) was given β-alanine powder. The subjects were randomly assigned to either the experimental or control groups. This study lasted four weeks, during which both groups participated in high-intensity interval training (HIFT) on the first day to induce fatigue and work close to their VO2 max. Statistically significant changes were in the sports performance variables, specifically vertical jump and jumping power (p = 0.027). These changes were observed only in the group that had been supplemented with β-alanine. Nevertheless, no alterations were observed in any other variables, including fatigue, metabolic intensity of exercise, or perceived intensity (p > 0.05). A four-week β-alanine intake program demonstrated an improvement in the capacity of subjects, as evidenced by enhanced vertical jump and power performance. Nevertheless, it does result in discernible alterations in performance.

Setting sail for Paris 2024: Retrospective analysis of world-class ILCA 7 Olympic sailors' cardiorespiratory fitness (2015-2020).

The aim of this retrospective analysis was to provide a more comprehensive understanding of the cardiorespiratory profile of world-class ILCA-7 sailors (n=3, all males), through a longitudinal evaluation offering real-world data on physiological profile and exercise intensity domains. The cardiopulmonary exercise testing (CPET) was performed by the same researchers using the same equipment during the study. Assessments took place twice a year, aligning with major international competition preparations. Participants trained and competed at the same sailing club in Split, Croatia, under consistent supervision from the same team throughout the study, winning a total of 21 medals at major international competitions. The recorded ranged from 51.7±1.6 to 61.9±3.0mLmin-1kg-1, respectively. Similarly, peak power output varied from 352±10 to 426±34W. The changes in physiological responses at the ventilatory thresholds were proportional to the changes in peak cardiorespiratory fitness capacity. Interestingly, the oxygen pulse measured in 2015 was 25±1mLO2beat-1. Over the subsequent 6 years, the O2 pulse marginally increased and appeared to stabilize at 27±1mLO2beat-1 in 2020, when these athletes were 32±3 years old. This work offers a broader understanding of world-class Olympic sailors' cardiorespiratory fitness, going beyond the standard assessment of peak to incorporate an analysis of ventilatory thresholds. While a direct link between cardiorespiratory fitness and competitive success remains ambiguous, the importance of a well-rounded aerobic capacity for excellence in ILCA-7 sailing class is evident. HIGHLIGHTS: What is the central question of this study? What are the temporal changes in the physiological profiles of three world-class ILCA-7 sailors? What is the main finding and its importance? Data on oxygen pulse adjustments suggest the involvement of compensatory cardiovascular mechanisms, likely associated with the isometric and quasi-isometric contractions inherent in ILCA-7 sailing. This is evidenced by the absence of an age-related increase in oxygen pulse, a phenomenon often observed in endurance athletes throughout their competitive careers.

Impact of probiotic supplementation on exercise endurance among non-elite athletes: a randomized, placebo-controlled, double-blind, clinical trial.

This randomized, placebo-controlled, double-blind, parallel trial investigated whether generally healthy adult, non-elite runners would have a greater time-to-exhaustion during submaximal treadmill running with probiotic versus placebo supplementation. It was hypothesized that the probiotic would impact training progression by reducing gastrointestinal (GI) and cold/flu symptoms. Participants who typically ran ≥24 km/week, ran or cross-trained 3-5 days per week, and had a maximal oxygen intake (VO2 max) in the 60-85th percentile were enrolled. VO2 max was used to establish individualized workload settings (85% of VO2 max) for the submaximal endurance tests at baseline and following 6 weeks of supplementation with a probiotic (Lactobacillus helveticus Lafti L10, 5x109 CFU/capsule/day) or placebo. Participants self-reported GI and cold/flu symptoms and physical activity via daily and weekly questionnaires. Outcomes were tested using a linear model to determine if mean response values adjusted for baseline differed between groups. Twenty-eight participants (n=14/group), aged 255 years (meanSD) with a body mass index of 233 kg/m2, completed the study. At the final visit the probiotic group had a lower time-to-exhaustion versus the placebo group (P=0.01) due to an increase in time-to-exhaustion with the placebo (1344±188 to 1565±219 seconds, P=0.01) with no change with the probiotic (1655±230 to 1547±215 seconds, P=0.23). During the intervention, the probiotic group completed fewer aerobic training sessions per week (P=0.02) and trained at a lower intensity (P=0.007) versus the placebo group. Few GI and cold/flu symptoms were reported with no differences between groups. Time-to-exhaustion increased in the placebo group, possibly due to differences in training habits.

Cardiorespiratory fitness associates negatively with arterial stiffness in a cohort of industrial workers followed up for 4 years.

Previously we have found increased carotid-to-femoral pulse wave velocity (cfPWV) among shift workers compared to day workers in industry, and a decline in maximal oxygen uptake (V̇O2max) in all 86 workers. Utilizing all available measurements in 2018, 2021 and 2022, this study investigated associations between V̇O2max and measures of arterial stiffness. Using a mixed model approach, we analysed the cross-sectional association between all V̇O2max (outcome) and measures of arterial stiffness (covariates). We observed a significant association between V̇O2max and cfPWV of -1.59 (95%CI -3.03, -0.16), augmentation pressure (AP) and augmentation index (Aix) of -0.32 (95%CI -0.58, -0.06) and -0.12 (95%CI -0.23, -0.005), respectively. We found a significant negative association between cardiorespiratory fitness and measures of arterial stiffness. The former and present results pose challenges for shift workers' future macro and microvascular health.

Impact of a 12-wk physical conditioning program on the aerobic capacity of aviation cadets.

Flight cadets need to have good physical fitness to cope with the challenges of flying missions. The continuous development of science and technology has led to the constant upgrading of fighter jets and the improvement of their performance, which has resulted in new and higher requirements for the physical fitness of flight personnel. The traditional physical training mode, method, and assessment have been used for many years and do not meet current fitness needs. To investigate the impact of a 12-wk comprehensive anti-G fitness training program on the aerobic capacity of aviation cadets and to evaluate its effectiveness. Fifty-five cadets were randomly assigned to control and experimental groups using a randomized, single-blind design. The control group maintained their existing training regimen, while the experimental group participated in a 12-wk comprehensive training intervention. The training program comprised strength training twice per week, high-intensity interval training three times per week, and supplemental nutritional and psychological support. Maximal oxygen uptake (VO2max), lower limb strength, and hemoglobin levels were measured at baseline, at 6 wk and 12 wk post-intervention. Repeated measures analysis of variance revealed significant differences of both VO2max and relative VO2 in both groups across time points (P < 0.05). However, no significant time-group interaction was observed (P > 0.05). Paired t-tests comparing baseline and 12-wk results showed that VO2max and relative VO2 were significantly higher in the experimental group than the control group (P < 0.05). This suggests that the training program effectively enhanced the aerobic capacity of the experimental group. Key indicators of aerobic capacity, bilateral lower limb strength and hemoglobin levels, were also significantly different over time and between groups (P < 0.05). No significant differences were noted in heart-rate metrics (P > 0.05). A 12-wk comprehensive anti-G fitness training program significantly improved the aerobic capacity of aviation cadets, thereby enhancing their overall capacity and laying a physiological foundation for enduring high-G flights.

Prehabilitation Consultation on Self-Care and Physical Exercise in Patients Diagnosed with Abdominopelvic Cancer: Protocol of the Study.

Introduction: Prehabilitation in the field of oncology has been defined as "the process in the continuum of care that occurs between diagnosis and the start of treatment involving physical and psychological measures that determine the patient's baseline functional status." To determine the effectiveness of a Prehabilitation consultation on self-care and targeted physical exercise for patients diagnosed with abdominopelvic cancer. An observational study that will evaluate the pre-post efficacy of an ad-hoc designed Prehabilitation intervention. The study population consists of patients diagnosed with colon or gynecological cancer with a surgical indication as part of their therapeutic plan from the General Surgery Services. It is configured around four key interventions: (a) health education and self-care, (b) specific nutritional counseling, (c) initial psychological assessment, and (d) directed physical exercise intervention. Health education, self-care interventions, and physical exercise will be carried out weekly from diagnosis to the scheduled surgery day. Aspects such as self-care capacity or agency, perioperative anxiety, aerobic capacity, strength and flexibility, postoperative complications, and recovery time to adjuvant treatment will be measured using tools such as Appraisal of self-care agency scale (ASA), State Trait Anxiety Inventory (STAI), walking test, sit and Reach, Hand Grip or Squad Jump. Utilizing validated tools for analyzing selected variables will contribute to refining and expanding care guidelines, ultimately enhancing support for both patients and their caregivers.

Energetics and Basic Stroke Kinematics of Swimming With Different Styles of Wetsuits.

Lim, B, Villalobos, A, Mercer, JA, and Crocker, GH. Energetics and basic stroke kinematics of swimming with different styles of wetsuits. J Strength Cond Res XX(X): 000-000, 2024-This study investigated the physiological responses and basic stroke kinematics while wearing different styles of wetsuits during submaximal intensity front-crawl swimming. Fourteen subjects (6 men and 8 women) completed a swimming-graded exercise test to determine maximal aerobic capacity (V̇O2max) and four 4-minute submaximal front-crawl swims at a pace that elicited 80% of V̇O2max with different wetsuits: regular swimsuit (no wetsuit [NWS]), buoyancy shorts (BS), sleeveless wetsuit (SLW), and full-sleeve wetsuit (FSW). The rate of oxygen consumption (V̇O2), rate of carbon dioxide production (V̇CO2), minute ventilation (V̇E), heart rate (HR), respiratory exchange ratio, and cost of swimming (CS) were determined as the average for the last minute of each trial. The rating of perceived exertion was assessed after each swimming bout. In addition, stroke length and index were determined from swimming pace and stroke rate. V̇O2, V̇CO2, V̇E, HR, and CS differed significantly among wetsuit conditions (p < 0.01). Respiratory exchange ratio and rating of perceived exertion also varied by wetsuit conditions (p < 0.05). However, stroke rate, length, and index were not significantly different across wetsuit conditions (p > 0.05). No differences existed between SLW and FSW for any dependent variable (p > 0.05). Results from this study suggest that swimming at the same pace without a wetsuit is the least economical, and both SLW and FSW are most and equally economical without significant kinematic changes. In addition, BS could be beneficial during training and racing in terms of less physiological demands than a regular swimsuit but not as economical as the SLW or FSW.

Physiological profile of professional handball players regarding playing position

In the handball game players occupied specific position which requires unique physiological and physical attributes relating to technical and tactical requirements of each position in order to maximize sport performance on the court. The aim of this study was to quantify anthropometrical and physiological characteristics in elite Macedonian handball players and compare them regarding four different playing positions. In this study were included 55 handball players, different nationality, from RNM, participated in ergometry testing with Bruce protocol and body mass analysis with bioelectrical impedance analyzer, InBody 720. The players were divided in four groups according to playing position: wings (W), backs (B), pivots (P) and goalkeepers (G). Anthropometric parameters for all players were following: mean height was 186.3  7.1 cm, weight = 85.37 ± 13.7 kg, skeletal muscle mass (SMM) = 42.04 ± 6.2 kg; BMI = 24.54 ± 2.8; BF%=13.4 ± 4.75 and WHR = 0.85 ± 0.06. Regarding the position, B/W/P/G for height were: 187.14cm /180.0cm/191.77cm/186.8cm; weight: 85.72/kg72.67kg/ 99.67kg/85.33kg; body fat percent: 12.26% /11.92% / 16.3% / 14.7%. The mean values for maximal oxygen consumption for B/W/P/G were 48.86 / 44.31 / 44.09 / 47.78 ml/kg/min. The BIA parameters of body composition in handball players regarding the playing position, showed statistically significant differences for all lean body mass parameters and obesity diagnose parameters, except for the body fat percent. According the cardio-physiological parameters derived from Bruce protocol handball players at different playing position had similar aerobic capacity.

Effects of systematic cardiac rehabilitation training in elderly patients with unstable angina following cardiac stent implantation.

Coronary stent implantation is usually used to treat unstable angina to alleviate stenosis or occlusion, promoting blood flow restoration and alleviating symptoms such as myocardial ischemia. And postoperative cardiac rehabilitation is essential for enhancing recovery and prognosis. Nevertheless, conventional rehabilitation lacks specificity, particularly for elderly patients with multiple comorbidities and poor compliance, rendering it less effective. To investigate the effects of systematic cardiac rehabilitation training in elderly patients with unstable angina following coronary stenting intervention. A retrospective enrollment was conducted comprising fifty-four elderly patients with unstable angina pectoris who underwent systematic cardiac rehabilitation training after receiving coronary intervention as the rehabilitation group, while fifty-three elderly patients who received basic nursing and rehabilitation guidance measures after coronary intervention were assigned to the control group. Differences in Seattle Angina Questionnaire scores, survival quality (SF-36) scores, cardiopulmonary exercise function assessment index, echocardiographic cardiac function index, and adverse cardiovascular events were compared between the two groups. After intervention, the rehabilitation group observed greater VO2 Max, maximum metabolic equivalent, eft ventricular ejection fraction, left ventricular end-diastolic diameter and smaller left ventricular end-systolic diameter. And the rehabilitation group observed greater scores of physical activity limitation, stable angina pectoris, treatment satisfaction, and SF-36 score. The incidence of adverse cardiovascular events in the two groups, showed no significant difference. Systematic cardiac rehabilitation following coronary stenting in elderly patients with unstable angina pectoris can enhance cardiac function recovery, consequently enhancing both quality of life and cardiopulmonary exercise tolerance.

Effects of Adapted Physical Activity on White Matter Integrity in Patients with Schizophrenia.

Schizophrenia is associated with changes in white matter (WM) integrity and with reduced life expectancy, in part because of the cardiometabolic side effects of antipsychotics. Physical activity (PA) has emerged as a candidate lifestyle intervention that is safe and effective. The study aimed to assess how an adapted PA program delivered remotely by web (e-APA) improved WM integrity in patients with schizophrenia (SZPs) and healthy controls (HCs) and to evaluate associations among WM integrity, cardiorespiratory fitness, and symptom severity. This longitudinal study was conducted over 16 weeks with 31 participants (18 SZPs and 13 HCs). Diffusion tensor imaging and tract-based spatial statistics were employed to assess WM integrity. Cardiorespiratory fitness was measured by maximal oxygen uptake (VO2max), and assessments for clinical symptoms included the Positive and Negative Syndrome Scale, Self-evaluation of Negative Symptoms and the Brief Negative Syndrome Scale (BNSS). Only the SZPs had significantly increased WM integrity after the e-APA program, with increased fractional anisotropy and decreased radial diffusivity in fasciculi involved in motor functions and language process. Furthermore, decreased negative symptoms assessed with BNSS were associated with greater WM integrity following the program. These findings suggest that e-APA may improve WM integrity abnormalities and support e-APA as a promising therapeutic strategy.

High-Intensity Interval vs. Moderate-Intensity Continuous Training in Parkinson's Disease: A Randomized Trial.

Exercise training is recommended to improve quality of life in those living with Parkinson's Disease (PD); however, the optimal prescription to improve cardiorespiratory fitness and disease-related motor symptoms remains unknown. Twenty-nine participants with PD were randomly allocated to either 10-weeks of high-intensity interval training (HIIT) (n=15; 6 female) or moderate-intensity continuous training (MICT) (n=14; 5 female). The primary outcome was the change in maximal oxygen consumption (VO2peak). Secondary outcomes included changes in the Unified Parkinson's Disease Rating Scale (UPDRS) Part III motor score, Parkinson's Disease Fatigue Scale (PFS-16), resting and exercise cardiovascular measures, gait, balance, and knee extensor strength and fatigability. Exercise training increased VO2peak (main effect of time, P<0.01), with a clinically-meaningful difference in the change following HIIT vs. MICT (∆3.7±3.7 vs. 1.7±3.2 ml∙kg-1∙min-1, P=0.099). The UPDRS motor score improved over time (P<0.001) but without any differences between HIIT vs. MICT (∆-9.7±1.3 vs. -8.4±1.4, P=0.51). Self-reported subjective fatigue (PFS-16) decreased over time (P<0.01) but was similar between HIIT and MICT groups (P=0.6). Gait, balance, blood pressure, and heart rate were unchanged with training (all P>0.09). Knee extensor strength increased over time (P=0.03) but did not differ between HIIT vs. MICT (∆8.2±5.9 vs. 11.7±6.2 Nm, P=0.69). HIIT alone increased muscular endurance of the knee extensors during an isotonic task to failure (P=0.04). In participants with PD, HIIT and MICT both increased VO2peak and led to improvements in motor symptoms and perceived fatigue; HIIT may offer the potential for larger changes in VO2peak and reduced knee extensor fatigability.

Adipose Kiss1 controls aerobic exercise-related adaptive responses in adipose tissue energy homeostasis.

Kisspeptin signaling regulates energy homeostasis. Adiposity is the principal source and receiver of peripheral Kisspeptin, and adipose Kiss1 metastasis suppressor (Kiss1) gene expression is stimulated by exercise. However, whether the adipose Kiss1 gene regulates energy homeostasis and plays a role in adaptive alterations during prolonged exercise remains unknown. Here, we investigated the role of Kiss1 role in mice and adipose tissues and the adaptive changes it induces after exercise, using adipose-specific Kiss1 knockout (Kiss1adipoq-/-) and adeno-associated virus-induced adipose tissue Kiss1-overexpressing (Kiss1adipoq over) mice. We found that adipose-derived kisspeptin signal regulates lipid and glucose homeostasis to maintain systemic energy homeostasis, but in a sex-dependent manner, with more pronounced metabolic changes in female mice. Kiss1 regulated adaptive alterations of genes and proteins in tricarboxylic acid (TCA) cycle and oxidative phosphorylation (OxPhos) pathways in female gWAT following prolonged aerobic exercise. We could further show that adipose Kiss1 deficiency leads to reduced peroxisome proliferator-activated receptor gamma co-activator 1 alpha (PGC-1α) protein content of soleus muscle and maximum oxygen uptake (VO2 max) of female mice after prolonged exercise. Therefore, adipose Kisspeptin may be a novel adipokine that increases organ sensitivity to glucose, lipids, and oxygen following exercise.

Influence of the CYP1A2 c.-163A > C polymorphism in the effect of caffeine on fat oxidation during exercise: a pilot randomized, double-blind, crossover, placebo-controlled trial.

The aim of this study was to determine the influence of the CYP1A2 c.-163A > C (rs762551) polymorphism on the effect of oral caffeine intake on fat oxidation during exercise. Using a pilot randomized, double-blind, crossover, placebo-controlled trial, 32 young and healthy individuals (women = 14, men = 18) performed an incremental test on a cycle ergometer with 3-min stages at workloads from 30 to 70% of maximal oxygen uptake (VO2max). Participants performed this test after the ingestion of (a) placebo; (b) 3mg/kg of caffeine; (c) 6mg/kg of caffeine. Fat oxidation rate during exercise was measured by indirect calorimetry. The influence of the CYP1A2 c.-163A > C polymorphism in the effect of caffeine on fat oxidation rates during exercise was established with a three-way ANOVA (substance × genotype × intensity). Eight participants were genotyped as AA, 18 participants were CA heterozygotes, and 6 participants were CC. There was a main effect of substance (F = 3.348, p = 0.050) on fat oxidation rates during exercise with no genotype effect (F = 0.158, p = 0.959). The post hoc analysis revealed that, in comparison to the placebo, 3 and 6mg/kg of caffeine increased fat oxidation at 40-50% VO2max in AA (all p < 0.050) and 50-60% VO2max in CA and CC participants (all p < 0.050). Oral intake of 3 and 6mg/kg of caffeine increased fat oxidation rate during aerobic exercise in individuals with AA, CA and CC genotypes. This suggests that the effect of caffeine to enhance fat oxidation during exercise is not influenced by the CYP1A2 c.-163A > C polymorphism. The study was registered on clinicaltrials.gov with ID: NCT05975489.

Association between recovery from desaturation after stair climbing and postoperative complications in lung resection.

The stair-climbing test (SCT) is used as a surrogate for cardiopulmonary exercise testing, which measures maximal oxygen uptake, and considered a useful method for assessing exercise capacity in thoracic surgery. This study aims to investigate whether the recovery time of percutaneous oxygen saturation (SpO2) after stair climbing is a predictor of postoperative complications after lobectomy. We retrospectively identified 54 patients who performed SCT and underwent lobectomy between January 2015 and February 2023 at Shizuoka Cancer Center. The SpO2 recovery time was defined as the time required to recover from the minimum to resting value after stair climbing. The association between SpO2 recovery time and early postoperative pulmonary complications within 30days after surgery was analyzed. Eleven patients (20.4%) had postoperative pulmonary complications (≥ Clavien-Dindo Classification Grade 2). The cutoff value of SpO2 recovery time obtained from the receiver operating characteristic curve analysis was 90s [sensitivity, 81.8%; specificity, 72.1%; AUC, 0.77 (95% confidence interval, 0.64-0.90)]. The occurrence of postoperative pulmonary complications was 42.9% in the delayed recovery time (DRT; SpO2 recovery time ≥ 90s) group and 6.1% in the non-DRT (SpO2 recovery time < 90s) group (p = 0.002). DRT was a predictor of postoperative pulmonary complications (odds ratio, 11.60; 95% CI 2.19-61.80). DRT of SpO2 after stair climbing is a predictor of postoperative pulmonary complications following lobectomy in borderline patients who require exercise capacity assessment. SpO2 monitoring after stair climbing may be useful as one of the preoperative assessments in patients undergoing lobectomy.

Expanding the scope: integrating costs of digestive metabolism and growth into estimates of maximum oxygen uptake in fishes.

Expanding the scope: integrating costs of digestive metabolism and growth into estimates of maximum oxygen uptake in fishes.

The relationship between aerobic capacity and left atrial size in healthy young males: An observational study.

Aerobic capacity, defined as peak oxygen uptake (peakVO2), is a marker for aerobic fitness and is associated with left ventricular (LV) systolic and diastolic function. The aim of the study was to explore the relation between left atrial (LA) volume index (LAVI) and aerobic capacity in healthy young male adults. One hundred three healthy young male subjects (mean age: 34.2 ± 5.5years) were consecutively included in the study. All subjects underwent echocardiography to assess LAVI, LV systolic and diastolic functions. Aerobic capacity was assessed by cardiopulmonary exercise testing. All patients had normal left ventricular ejection fraction (LVEF). One hundred one subjects had normal LAVI (≤34 mL/m2) while 2 subjects had mildly increased LAVI (35-41 mL/m2). Mean peakVO2 predicted was 82.2 ± 14.4%. 64subjects (62.1%) had a peakVO2 < 85% of age-predicted and sex-predicted values and they had higher LAVI compared to those who had a peakVO2 higher than 85% of age-predicted and sex-predicted values (22.0 ± 4.8 mL/m2 vs 20.3 ± 4.1 mL/m2, P = .055). Notably, only LAVI showed a significant correlation with peakVO2 and predicted breathing reserve (BR), while anaerobic threshold correlated with both LAVI and LVEF. Age was also a significant factor, negatively impacting peakVO2 (r = -0.265, P = .007) and predicted BR (r = -0.282, P = .004). Multivariate analysis revealed that both LAVI and age were independent predictors of peakVO2 and predicted BR. This study suggests that LAVI can be a valuable indicator of aerobic capacity in apparently healthy young males.

Phase Angle as Surrogate Marker of Muscle Weakness in Kidney Transplant Candidates Referred to Prehabilitation.

Phase angle (PhA), a marker of nutritional status obtained by bioelectrical impedance analysis (BIA), is associated with the integrity of cell membranes. Damage to muscle fiber membranes can impact muscle strength, which is related to adverse outcomes in adults with advanced chronic kidney disease (CKD). The main objective of this study was to determine the usefulness of the PhA in identifying muscle weakness in candidates for kidney transplants (KTs). Secondly, it aimed to examine the associations of PhA with other parameters of body composition, exercise performance, and muscle structure. Sensitivity, specificity, and area under the receiver operating characteristics curve were used to evaluate the PhA (index test) as a biomarker of muscle weakness. Muscle strength was estimated with maximal voluntary isometric contraction of the quadriceps (MVCI-Q) of the dominant side. Muscle weakness was defined as MVIC-Q < 40% of body weight. A total of 119 patients were evaluated (mean age 63.7 years, 75.6% men). A phase angle cut-off of 5.1° was identified to classify men with a higher likelihood of having low muscle strength in upper limbs (MVIC-Q 40% of their body weight). Male KT candidates with PhA < 5.1° had poorer exercise capacity, lower muscle strength, less muscle mass, and smaller muscle size. A PhA < 5.1° was significantly associated with an eight-fold higher muscle weakness risk (OR = 8.2, 95%CI 2.3-29.2) in a binary regression model adjusted by age, frailty, and hydration status. Remarkably, PhA is an easily obtainable objective parameter in CKD patients, requiring no volitional effort from the individual. The associations of PhA with aerobic capacity, physical activity, muscle mass, and muscle size underscore its clinical relevance and potential utility in the comprehensive evaluation of these patients.

Application of Principal Component Analysis to Heterogenous Fontan Registry Data Identifies Independent Contributing Factors to Decline.

Single ventricle heart disease is a severe and life-threatening illness, and improvements in clinical outcomes of those with Fontan circulation have not yet yielded acceptable survival over the past two decades. Patients are at risk of developing a diverse variety of Fontan-associated comorbidities that ultimately requires heart transplant. Our observational cohort study goal was to determine if principal component analysis (PCA) applied to data collected from a substantial Fontan cohort can predict functional decline (N=140). Heterogeneous data broadly consisting of measures of cardiac and vascular function, exercise (VO 2max ), lymphatic biomarkers, and blood biomarkers were collected over 11 years at a single site; in that time, 16 events occurred that are considered here in a composite outcome measure. After standardization and PCA, principal components (PCs) representing >5% of total variance were thematically labeled based on their constituents and tested for association with the composite outcome. Our main findings suggest that the 6 th PC (PC6), representing 7.1% percent of the total variance in the set, is greatly influenced by blood serum biomarkers and superior vena cava flow, is a superior measure of proportional hazard compared to EF, and displayed the greatest accuracy for classifying Fontan patients as determined by AUC. In bivariate hazard analysis, we found that models combining systolic function (EF or PC5) and lymphatic dysfunction (PC6) were most predictive, with the former having the greatest AIC, and the latter having the highest c-statistic. Our findings support our hypothesis that a multifactorial model must be considered to improve prognosis in the Fontan population.

The Physiological and Performance Development of Two Multiple Olympic Champion Rowers: A 20-Year Follow-Up Study.

This study reports the results of a 20-year (2005-2024) follow-up study of two 2-time Olympic and 6-time world champion rowing athletes. To provide a comprehensive picture of adaptations in physiological and performance characteristics to long-term training, we monitored the athletes' physiological and performance data annually through five 4-year developmental phases. Maximal oxygen uptake (V̇O2max), maximal minute power (MMP), and power output corresponding to anaerobic threshold (PAT) were derived from a ramp-wise exercise test on a rowing ergometer. Additionally, average power output sustained during all-out tests over 2000-m and 6000-m on a rowing ergometer was also obtained. V̇O2max peaked at age 22 for Athlete A and at age 25 for Athlete B (at ~7 L·min-1), before stabilizing and then gradually declining to a range of 6.2-6.5 L·min-1 for both athletes. MMP stabilized in both rowers at values between 550 and 575 W and displayed minimal fluctuations over the final two phases of the study. Additionally, MMP closely resembled the corresponding average power output sustained during the 2000-m all-out tests on a rowing ergometer. Average power output during 2000-m and 6000-m all-out tests showed steady improvements over the monitored phases of the study, with highest power output crew averages for both 2000-m (532 W; 5 min 48 s) and 6000-m (463 W; 18 min 4 s) tests recorded during the last 4-year phase of the assessment. Improvements in rowing ergometer performance over 2000-m and 6000-m appear to be largely independent of the multi-year changes in V̇O2max. Long-term rowing training resulted in continuous improvements in MMP and PAT throughout the monitored phases, which more closely mimicked improvements in rowing ergometer performance.