Search Results (43)

Background/Objectives: Gut-derived tryptophan (Trp) metabolites play important roles in metabolic and cardiovascular regulation. Although animal studies suggest their protective effects against metabolic dysfunction, data in adolescents, particularly those with obesity, remain limited. The objective of this study was to evaluate associations between circulating gut-derived Trp metabolites and markers of cardiometabolic, vascular, and platelet health in adolescents with obesity. Methods: Data were analyzed from 28 adolescents (ages 13–18; mean BMI = 36 ± 6.4 kg/m²). Fasting blood was collected to assess lipid profiles using a clinical analyzer and insulin resistance using the homeostatic model assessment for insulin resistance (HOMA-IR). Gut-derived Trp metabolites were measured by UPLC–mass spectrometry, peak oxygen uptake (VO_{2 peak}) by gas exchange during an incremental cycle ergometer test, and body composition by dual-energy X-ray absorptiometry. Platelet spare respiratory capacity (SRC), endothelial function, and liver fat were measured using high-resolution respirometry, flow-mediated dilation (FMD) of the brachial artery, and magnetic resonance imaging respectively. Results: Indole-3-propionic acid was inversely associated with diastolic blood pressure (rho = −0.39, p = 0.047), total cholesterol (rho = −0.55, p = 0.002), and LDL-C (rho = −0.57, p = 0.0014), independent of sex and obesity severity. Indoxyl sulfate was positively correlated with fasting glucose (rho = 0.47, p = 0.012), and adolescents with impaired fasting glucose had 1.6-fold higher IS levels. Indole-3-acetaldehyde declined with age (rho = −0.50, p = 0.007), and Indole-3-acetic acid and indole were higher in Hispanics vs. non-Hispanics. No significant associations were observed between Trp metabolites and FMD, VO₂ peak, or SRC. Conclusions: Gut-derived Trp metabolites, particularly indole-3-propionic and indoxyl sulfate, are associated with markers of cardiometabolic risk in adolescents with obesity. These findings support their potential relevance in early-onset cardiovascular disease risk. Full article

Background: This study aimed to evaluate the changes in fat utilization associated with transitioning from a traditional to a vegan Mediterranean diet in healthy, physically active men during a ramp exercise test. Methods: In a controlled crossover design, fourteen healthy, physically active men followed a traditional Mediterranean diet for three weeks (baseline). Then, participants transitioned to a four-week isocaloric vegan version of the Mediterranean diet, matched for macronutrient distribution but excluding all animal foods. Immediately after each dietary intervention, participants completed an incremental exercise test (from 30% to 70% of VO_2peak) on a cycle ergometer in a fasted state to determine peak fat oxidation (PFO) and its associated exercise intensity (Fatmax). Exercise heart rate and the rating of perceived exertion were also recorded at each exercise intensity. Results: The traditional and vegan Mediterranean diets provided comparable amounts of energy (2599.6 ± 180.8 and 2634.9 ± 148.3 kcal/day, p = 0.140) and total fat (97.0 ± 17.8 and 99.0 ± 13.2 g/day; p = 0.620). However, the vegan Mediterranean diet contained a lower proportion of saturated fat (25.2 ± 6.8 vs. 13.6 ± 4.4% of total fat, p < 0.010). Still, the dietary transition was not associated with modifications in PFO (0.323 ± 0.153 and 0.347 ± 0.147 g/min; p = 0.678) or Fatmax (40.51 ± 7.30 and 40.51 ± 10.71%VO_2peak; p = 1.000) during exercise. Moreover, the dietary transition did not significantly change the response curves across exercise intensities for fat oxidation (p = 0.553), heart rate (p = 0.280), or the rating of perceived exertion (p = 0.433). Conclusions: Switching from a traditional to a vegan Mediterranean diet did not affect fat oxidation, exercise intensity at peak fat oxidation, or perceptual responses during exercise in healthy, active men. These findings suggest that physically active individuals can adopt a vegan version of the Mediterranean diet without compromising fat utilization during submaximal aerobic exercise. Clinical Trial Registry: NCT06008886. Date of registration: 28 July 2023. Full article

This study aimed to (1) determine and compare the magnitude and direction of asymmetry in lower limbs neuromuscular properties, range of motion, strength and muscle electrical activity (EMG) in well-trained male road cyclist across categories (elite, under-23 and junior); (2) establish test- and age-specific asymmetry thresholds for these variables to enable individualized classification; and (3) examine the relationship between these lateral asymmetries and performance in a maximal incremental cycle ergometer test. Fifty-five well-trained road cyclists were assessed through tensiomyography (TMG), active knee extension test (AKE), leg press and EMG of vastus lateralis (VL-EMG) during a maximal incremental cycling test. Junior cyclists showed lower asymmetry in VM than elite cyclists, but greater asymmetry in AKE. No significant differences were found in strength or VL-EMG during the maximal incremental cycle ergometer test. The magnitude and direction of lateral asymmetry differs between tests (TMG: 11.3–21.3%; AKE: 2.3%; leg-press: 9.8–31.9%; VL-EMG: 20.8–22.7%). Multiple linear regression revealed a significant predictive model for maximal incremental cycling ergometer performance based on lateral asymmetry in AKE, leg press and VL and rectus femoris contraction time (R²_a = 0.23). These reference data can support trainers in monitoring and managing lateral asymmetry throughout the cyclists’ season. Full article

This study evaluates the performance of a 32-marker motion capture (MoCap) system in estimating respiratory frequency ($f_R$) and tidal volume ($V_T$) during cycling exercise. Fourteen well-trained cyclists performed an incremental step test on a cycle ergometer, while simultaneously recording a raw flow signal with a reference metabolic cart (COSMED) and respiratory-induced torso movements with twelve optoelectronic cameras registering the position of 32 markers affixed to the torso. $f_R$ and $V_T$ were calculated from both systems on a breath-by-breath basis. The MoCap system showed a strong correlation with the COSMED system when measuring $f_R$ and $V_T$ ($r^2$ = 0.99, $r^2$ = 0.87, respectively) during exercise. For $f_R$, the mean absolute error (MAE) and mean absolute percentage error (MAPE) were 0.79 breaths/min and 2.1%, respectively. For $V_T$, MoCap consistently underestimated values compared to COSMED, showing a bias (MOD ± LOA) of −0.11 ± 0.42 L and MAPE values of 8%. These findings highlight the system’s capabilities for real-time respiratory monitoring in athletic environments. Full article

Background: High-intensity interval training (HIIT) is an effective and efficient method for training Paralympic athletes with cerebral palsy, particularly in intermittent sports and those requiring aerobic and anaerobic capacity, speed, and strength to delay fatigue onset and optimize athletic performance. Objectives: This study aimed to analyze the effects of four weeks of HIIT on the estimated VO₂max, anaerobic power, and athletic performance in cyclists with cerebral palsy. Materials and Methods: This quasi-experimental study included three male athletes (Athletes A, B, and C) with cerebral palsy from the Paracycling Departmental Commission of Cauca, Colombia. The estimated VO₂max was assessed using an incremental test on a cycling ergometer. Anaerobic power was measured using the 30 s long Wingate Anaerobic Test (WAnT_30 s. Specific performance was evaluated with an individual time trial of 14 km for class T1 and 20 km for class T2. HIIT training was performed on a cycling ergometer over four weeks (two sessions per week). The training intensity was based on watts (W) measured in the incremental test for long HIIT sessions and in the WAnT_30 s test for short HIIT sessions. The training load was monitored through heart rate (HR) responses and the subjective perceived exertion (RPE) at the end of the training. Results: After the HIIT intervention, percentage changes in the estimated VO₂max were observed in Athlete A (+7%) and Athlete C (+9.4%). In the WAnT_30 s, there were increases in the maximal and mean power in Athlete A (>31%, 282.3 vs. 370.4 W), Athlete B (>15%, 272.5 vs. 312.6 W), and Athlete C (>9%, 473.7 vs. 516.2 W). Individual time trial performance improved, with reduced completion times for Athlete A (−6.7%, 2492 vs. 2325 s), Athlete B (−3.7%, 2486 vs. 2390 s), and Athlete C (−3.7%, 2775 vs. 2674 s). Conclusions: This study found that eight sessions of high-intensity interval training (HIIT) over a four-week period had a positive effect on the estimated VO₂max in Athletes A and C. Moreover, all three paracyclists demonstrated improvements in their maximal and average power output during the 30 s Wingate Anaerobic Test (WAnT_30 s), as well as enhanced performance in the time trial test. Full article

Background and Objectives: Cardiovascular diseases (CVD) are the primary causes of death throughout the world. Engaging in physical activity (PA) is crucial for the prevention of CVD, as a lack of exercise significantly impacts global health. For health promotion purposes, it is important to optimize PA and develop the main physical components. Multimodal exercise program (MEP) interventions cause unique cardiac changes that can be systematically analyzed using advanced ECG techniques. Using algebraic co-integration methods, this study examined the physiological cardiac adaptations of a 6-week MEP compared to sedentary control subjects. Materials and Methods: A total of 50 physically inactive males, aged 20–35 years, were recruited for a 6-week MEP. The intervention group (IG) consisted of 28 participants, while the control group (CG) included 22 participants. The MEP included balance, endurance, muscle strength, and flexibility exercises in one session. The cardiovascular system (CVS) was assessed using electrocardiography (ECG) and arterial blood pressure during an incremental cycle ergometer test, both before and after the 6-week period. Results: After the post-MEP, the IG’s resting HR showed a slight but insignificant decrease, from 84.5 to 82 bpm, with improved recovery rates at minute 1 (113.1–104.7 bpm). The CG showed a similar trend. pBP in IG significantly increased post-MEP during recovery at minute 1 (73–81) and minute 2 (65–72), where the CG showed a slight but significant difference. DskJT-QRS in IG post-MEP increased significantly during recovery in minutes 1–4, with all values showing p < 0.05. CG showed significance only at minute 3. Conclusions: Both the 6-week MEP and control had a positive impact on the CVS. The statement refers to changes in dynamic interactions between ECG parameters registered during the incremental exercise test and especially during the recovery after workload. Algebraic data co-integration analysis of ECG parameters demonstrated a sensitive assessment of the influence of exercising on the cardiovascular system. Full article

The purpose of this study was to determine the accuracy and inter-device reliability of the OTBeat Burn^TM heart rate monitor during an incremental test to exhaustion on a cycle ergometer. Twenty males (mean ± SD age = 21.1 ± 1.9 years) volunteered to complete a test to exhaustion on a cycle ergometer with OTBeat Burn^TM devices placed on the forearm and upper arm, with a 12-lead electrocardiogram used as the criterion. The heart rate was recorded every 30 s and averaged across each two-minute stage. Accuracy was assessed through calculation of the mean absolute percent error (MAPE), Bland–Altman plot, and Lin’s concordance correlation coefficient (CCC). An intraclass correlation coefficient (ICC) was used to assess the inter-device reliability. Statistical significance was set at α < 0.05. The MAPE (±SD), Bland–Altman regression analyses, and Lin’s CCC values were 0.9 (±0.6)% and 0.8 (±0.5)%, r = 0.107 and 0.303, and r_c = 0.998 and 0.998 for the forearm and the upper arm monitors, respectively. The ICC for inter-device reliability was R = 0.999. Our findings indicated the OTBeat Burn^TM monitors placed on the forearm and upper arm provided highly accurate and reliable values when compared to an electrocardiogram from low to maximal exercise intensities. Full article

The maximal rate of fat oxidation (MFO, in g∙min⁻¹) and the relative exercise intensity at which it occurs (FAT_max, as %V̇O_2max) are indexes of metabolic flexibility. The time-consuming, graded exercise protocol required for MFO/FAT_max determination hinders the extensive use of these indexes for individualized exercise prescription and monitoring. Purpose: validate ramp testing for MFO and FAT_max measures in postmenopausal women. Methods: Seventeen healthy women (age: 54 ± 4 years, BMI 22 ± 3 kg·m⁻², and V̇O_2max 36.4 ± 5.3 mL·min⁻¹), who were 4 ± 3 years from menopause, performed on a cycle-ergometer, a ramp, and a graded incremental test. Based on V̇O₂ and respiratory exchange ratio from the ramp and graded protocol (i.e., the 5th minute of each step), MFO and FAT_max were determined. Data from the two protocols were compared using paired t-tests, linear regression, and Bland–Altman analysis. Results: The MFO measured with a ramp protocol was not different from (0.24 ± 0.09 vs. 0.20 ± 0.08 g·min⁻¹, p = 0.10), and moderately associated with, that of the graded protocol (r² = 0.46). FAT_max occurred at similar exercise intensity for both protocols (47.8 ± 5.1 vs. 47.5 ± 4.3 %V̇O_2max, p = 0.91, r² = 0.52). The comparison of MFO and FAT_max across the protocols yields a non-significant bias but a relatively large limit of agreement (respectively, 0.05 g·min⁻¹, LOA = −0.08, and 0.19 g·min⁻¹; 0.3 %V̇O_2max, LOA = −7.8, and 10.6 %V̇O_2max). Conclusions: In postmenopausal women, ramp testing offers a valid alternative to the graded protocol for identifying MFO and FAT_max. The availability of a time- and cost-efficient approach, which can be incorporated into standard ramp incremental testing, can facilitate using these indexes of metabolic flexibility in research and medicine. Full article

Background: The incremental exercise test is commonly used to measure maximal oxygen uptake (VO₂max), but an additional verification test is often recommended as the “gold standard” to confirm the true VO₂max. Therefore, the aim of this study was to compare the peak oxygen uptake (VO₂peak) obtained in the ramp incremental exercise test and that in the verification test performed on different days at submaximal intensity. Additionally, we examined the roles of anaerobic performance and respiratory muscle strength. Methods: Sixteen physically active men participated in the study, with an average age of 22.7 ± 2.4 (years), height of 178.0 ± 7.4 (cm), and weight of 77.4 ± 7.3 (kg). They performed the three following tests on a cycle ergometer: the Wingate Anaerobic Test (WAnT), the ramp incremental exercise test (IET_RAMP), and the verification test performed at an intensity of 85% (VER₈₅) maximal power, which was obtained during the IET_RAMP. Results: No significant difference was observed in the peak oxygen uptake between the IET_RAMP and VER₈₅ (p = 0.51). The coefficient of variation was 3.1% and the Bland–Altman analysis showed a high agreement. We found significant correlations between the total work performed in the IET_RAMP, the anaerobic peak power (r = 0.52, p ≤ 0.05), and the total work obtained in the WAnT (r = 0.67, p ≤ 0.01). There were no significant differences in post-exercise changes in the strength of the inspiratory and expiratory muscles after the IET_RAMP and the VER₈₅. Conclusions: The submaximal intensity verification test performed on different days provided reliable values that confirmed the real VO₂max, which was not limited by respiratory muscle fatigue. This verification test may be suggested for participants with a lower anaerobic mechanical performance. Full article

We investigated the acute biophysical responses of changing the mandibular position during a rowing incremental protocol. A World-class 37-year-old male rower performed two 7 × 3 min ergometer rowing trials, once with no intraoral splint (control) and the other with a mandibular forward repositioning splint (splint condition). Ventilatory, kinematics and body electromyography were evaluated and compared between trials (paired samples t-test, p ≤ 0.05). Under the splint condition, oxygen uptake was lower, particularly at higher exercise intensities (67.3 ± 2.3 vs. 70.9 ± 1.5 mL·kg⁻¹·min⁻¹), and ventilation increased during specific rowing protocol steps (1st–4th and 6th). Wearing the splint condition led to changes in rowing technique, including a slower rowing frequency ([18–30] vs. [19–32] cycles·min⁻¹) and a longer propulsive movement ([1.58–1.52] vs. [1.56–1.50] m) than the control condition. The splint condition also had a faster propulsive phase and a prolonged recovery period than the control condition. The splint reduced peak and mean upper body muscle activation, contrasting with an increase in lower body muscle activity, and generated an energetic benefit by reducing exercise cost and increasing rowing economy compared to the control condition. Changing the mandibular position benefited a World-class rower, supporting the potential of wearing an intraoral splint in high-level sports, particularly in rowing. Full article

Facioscapulohumeral dystrophy (FSHD) leads to progressive changes in body composition such as loss of muscle mass and increase in adiposity. In healthy subjects, anthropometric parameters are associated with the maximum volume of oxygen consumed per minute (VO₂max), which is a health and function indicator in several populations of subjects, both healthy and pathological. Since VO₂max can be difficult to test in patients with FSHD due to exercise intolerance, the identification of associated anthropometric parameters could provide new easily obtainable elements for the patients’ clinical stratification. The aim of this study was to evaluate whether anthropometric and body composition parameters are associated with VO₂max in patients with FSHD. A total of 22 subjects with a molecular genetics-based diagnosis of FSHD (6 females, 16 males, mean age of 35.18 years) were recruited for the study. VO₂max was measured by cardiopulmonary exercise tests (CPETs) on a cycle ergometer, utilizing a step incremental technique (15 Watts (W) every 30 s). Weight (Kg) and height (m) were obtained and utilized to calculate body mass index (BMI). Body composition parameters (fat mass (FM), fat free mass (FFM), and body cell mass (BCM)) were obtained by bioelectrical impedance analysis (BIA). Significant negative associations were found between VO₂max and FM (Spearman correlation coefficient (SCC) −0.712), BMI (SCC −0.673), age (SCC −0.480), and weight (SCC −0.634), unlike FFM and BCM. Our results indicate that FM, BMI, age, and body weight are negatively associated with VO₂max in patients with FSHD. This evidence may help practitioners to better stratify patients with FSHD. Full article

The Q-LAC analyzer, a portable device employing near-infrared spectroscopy (NIRS), was designed to measure muscle oxygen saturation (SmO₂) during physical exercise. This study aimed to assess the reliability of the Q-LAC analyzer in determining SmO₂ levels during incremental cycling exercise. Thirteen physically active males (age 28.1 ± 5.3 y; height 181.2 ± 5.7 cm; body mass 79.9 ± 11.1 kg; BMI 24.2 ± 2.4 kg/m²) participated in this study. A submaximal incremental exercise test (SIET) on an electromagnetic cycle ergometer with a seven-day interval was performed twice. SmO₂ levels in the vastus lateralis (VL) muscle of the dominant leg were simultaneously recorded using the Q-LAC device during both tests. The study calculated the intraclass correlation coefficient (ICC), the coefficient of variation (CV), the standard error of measurement (SEM), the smallest worthwhile change (SWC), and mean detectable change (MDC). A within-within-subjects ANOVA revealed no statistically significant effects for session (F_1,12 = 0.97, p = 0.34, η² = 0.07) and the interaction between session and workload (F_4,48 = 0.19, p = 0.94, η² = 0.02). ICC values ranged from 0.72 to 0.91. Furthermore, the analysis of CV, SEM, and SWC indicated that SmO₂ measurements obtained with the Q-LAC device exhibit good reliability but marginal sensitivity. In conclusion, the portable Q-LAC analyzer provides consistent measurements of muscle oxygen saturation during low-to-moderate-intensity exercise on a cycle ergometer. Full article

Background: Despite a successful repair of tetralogy of Fallot (rToF) in childhood, residual lesions are common and can contribute to impaired exercise capacity. Although both cycle ergometer and treadmill protocols are often used interchangeably these approaches have not been directly compared. In this study we examined cardiopulmonary exercise test (CPET) measurements in rToF. Methods: Inclusion criteria were clinically stable rToF patients able to perform a cardiac magnetic resonance imaging (CMR) and two CPET studies, one on the treadmill (incremental Bruce protocol) and one on the cycle ergometer (ramped protocol), within 12 months. Demographic, surgical and clinical data; functional class; QRS duration; CMR measures; CPET data and international physical activity questionnaire (IPAQ) scores of patients were collected. Results: Fifty-seven patients were enrolled (53% male, 20.5 ± 7.8 years at CPET). CMR measurements included a right ventricle (RV) end-diastolic volume index of 119 ± 22 mL/m², a RV ejection fraction (EF) of 55 ± 6% and a left ventricular (LV) EF of 56 ± 5%. Peak oxygen consumption (VO₂)/Kg (25.5 ± 5.5 vs. 31.7 ± 6.9; p < 0.0001), VO₂ at anaerobic threshold (AT) (15.3 ± 3.9 vs. 22.0 ± 4.5; p < 0.0001), peak O₂ pulse (10.6 ± 3.0 vs. 12.1± 3.4; p = 0.0061) and oxygen uptake efficiency slope (OUES) (1932.2 ± 623.6 vs. 2292.0 ± 639.4; p < 0.001) were significantly lower on the cycle ergometer compared with the treadmill, differently from ventilatory efficiency (VE/VCO₂) max which was significantly higher on the cycle ergometer (32.2 ± 4.5 vs. 30.4 ± 5.4; p < 0.001). Only the VE/VCO₂ slope at the respiratory compensation point (RCP) was similar between the two methodologies (p = 0.150). Conclusions: The majority of CPET measurements differed according to the modality of testing, with the exception being the VE/VCO₂ slope at RCP. Our data suggest that CPET parameters should be interpreted according to test type; however, these findings should be validated in larger populations and in a variety of institutions. Full article

(1) Background: The breathing pattern is defined as the relationship between the tidal volume (VT) and breathing frequency (BF) for a given VE. The aim of this study was to evaluate whether inspiratory muscle training influenced the response of the breathing pattern during an incremental effort in amateur cyclists. (2) Methods: Eighteen amateur cyclists completed an incremental test to exhaustion, and a gas analysis on a cycle ergometer and spirometry were conducted. Cyclists were randomly assigned to two groups (IMTG = 9; CON = 9). The IMTG completed 6 weeks of inspiratory muscle training (IMT) using a PowerBreathe K3^® device at 50% of the maximum inspiratory pressure (Pimax). The workload was adjusted weekly. The CON did not carry out any inspiratory training during the experimental period. After the 6-week intervention, the cyclists repeated the incremental exercise test, and the gas analysis and spirometry were conducted. The response of the breathing pattern was evaluated during the incremental exercise test. (3) Results: The Pimax increased in the IMTG (p < 0.05; d = 3.1; +19.62%). Variables related to the breathing pattern response showed no differences between groups after the intervention (EXPvsCON; p > 0.05). Likewise, no differences in breathing pattern were found in the IMTG after training (PREvsPOST; p > 0.05). (4) Conclusions: IMT improved the strength of inspiratory muscles and sport performance in amateur cyclists. These changes were not attributed to alterations in the response of the breathing pattern. Full article

Using the upper limbs to test cardiopulmonary exercise can be a useful option in the case of individuals who are unable to pedal a bicycle due to lower limb injury or disability. We evaluated whether exercise testing with the upper limbs can be used equivalently to that of the lower limbs in assessing exercise capacity. Nine collegiate rowers and eight collegiate cyclists underwent incremental exercise testing with an arm crank ergometer (ACE) and cycle ergometer (CE). Heart rate (HR) and oxygen uptake (VO₂) were monitored throughout the tests. Segmental muscle mass and flow-mediated dilation of brachial artery were measured to assess the training status of the upper limbs. The muscle mass of the brachium, upper limb, and trunk were greater in the rowers than in the cyclists (p < 0.05). The correlations between HR and VO₂ was significantly different depending on exercise modalities, ACE and CE, in both groups (p < 0.001). The estimated maximal VO₂ using the correlation formula and age-predicted maximal HR was significantly lower in the exercise testing group with ACE than in the group with CE in rowers and cyclists (41.7 ± 7.3 vs. 52.6 ± 8.6 mL/kg/min, p = 0.010 and 35.5 ± 14.2 vs. 50.4 ± 13.4 mL/kg/min, p = 0.011, respectively). The results suggested that exercise capacity assessed by exercise testing with ACE is underestimated, regardless of the training status of the upper limbs. Further research is needed to verify factors which affect the correlations between HR and VO₂ during upper- and lower-limb exercise. Full article