Prediction of Exercise Tolerance in the Severe and Extreme Intensity Domains by a Critical Power Model
Ontology highlight
ABSTRACT:
SUBMITTER: Ventura T
PROVIDER: S-EPMC10694707 | biostudies-literature | 2023 Sep
REPOSITORIES: biostudies-literature
Similar Datasets
Project description:Maximal voluntary contraction force (MVC), potentiated twitch force (Qpot), and voluntary activation (%VA) recover to baseline within 90 s following extreme-intensity exercise. However, methodological limitations mask important recovery kinetics. We hypothesized reductions in MVC, Qpot, and %VA at task failure following extreme-intensity exercise would be less than following severe-intensity exercise, and Qpot and MVC following extreme-intensity exercise would show significant recovery within 120 s but remain depressed following severe-intensity exercise. Twelve subjects (6 men) completed 2 severe-intensity (40, 50% MVC) and 2 extreme-intensity (70, 80% MVC) isometric knee-extension exercise bouts to task failure (Tlim). Neuromuscular function was measured at baseline, Tlim, and through 150 s of recovery. Each intensity significantly reduced MVC and Qpot compared with baseline. MVC was greater at Tlim (p < 0.01) and at 150 s of recovery (p = 0.004) following exercise at 80% MVC compared with severe-intensity exercise. Partial recovery of MVC and Qpot were detected within 150 s following Tlim for each exercise intensity; Qpot recovered to baseline values within 150 s of recovery following exercise at 80% MVC. No differences in %VA were detected pre- to post-exercise or across recovery for any intensity. Although further analysis showed sex-specific differences in MVC and Qpot, future studies should closely examine sex-dependent responses to extreme-intensity exercise. It is clear, however, that these data reinforce that mechanisms limiting exercise tolerance during extreme-intensity exercise recover quickly. Novelty: Severe- and extreme-intensity exercise cause independent responses in fatigue accumulation and the subsequent recovery time courses. Recovery of MVC and Qpot occurs much faster following extreme-intensity exercise in both men and women.
| S-EPMC8969115 | biostudies-literature
Project description:PurposeWe investigated the cardiovascular individual response to 6 weeks (3×/week) of work-matched within the severe-intensity domain (high-intensity interval training, HIIT) or moderate-intensity domain (moderate-intensity continuous training, MICT). In addition, we analyzed the cardiovascular factors at baseline underlying the response variability.Methods42 healthy sedentary participants were randomly assigned to HIIT or MICT. We applied the region of practical equivalence-method for identifying the levels of responders to the maximal oxygen uptake (V̇O2max) response. For investigating the influence of cardiovascular markers, we trained a Bayesian machine learning model on cardiovascular markers.ResultsDespite that HIIT and MICT induced significant increases in V̇O2max, HIIT had greater improvements than MICT (p < 0.001). Greater variability was observed in MICT, with approximately 50% classified as "non-responder" and "undecided". 20 "responders", one "undecided" and no "non-responders" were observed in HIIT. The variability in the ∆V̇O2max was associated with initial cardiorespiratory fitness, arterial stiffness, and left-ventricular (LV) mass and LV end-diastolic diameter in HIIT; whereas, microvascular responsiveness and right-ventricular (RV) excursion velocity showed a significant association in MICT.ConclusionOur findings highlight the critical influence of exercise-intensity domains and biological variability on the individual V̇O2max response. The incidence of "non-responders" in MICT was one third of the group; whereas, no "non-responders" were observed in HIIT. The incidence of "responders" was 11 out of 21 participants in MICT, and 20 out of 21 participants in HIIT. The response in HIIT showed associations with baseline fitness, arterial stiffness, and LV-morphology; whereas, it was associated with RV systolic function in MICT.
| S-EPMC8192395 | biostudies-literature
Project description:PURPOSE:We compared a new locomotor-specific model to track the expenditure and reconstitution of work done above critical power (W´) and balance of W´ (W´BAL) by modelling flat over-ground power during exhaustive intermittent running. METHOD:Nine male participants completed a ramp test, 3-min all-out test and the 30-15 intermittent fitness test (30-15 IFT), and performed a severe-intensity constant work-rate trial (SCWR) at the maximum oxygen uptake velocity (vV̇O2max). Four intermittent trials followed: 60-s at vV̇O2max + 50% Δ1 (Δ1 = vV̇O2max - critical velocity [VCrit]) interspersed by 30-s in light (SL; 40% vV̇O2max), moderate (SM; 90% gas-exchange threshold velocity [VGET]), heavy (SH; VGET + 50% Δ2 [Δ2 = VCrit - VGET]), or severe (SS; vV̇O2max - 50% Δ1) domains. Data from Global Positioning Systems were derived to model over-ground power. The difference between critical and recovery power (DCP), time constant for reconstitution of W´ ([Formula: see text]), time to limit of tolerance (TLIM), and W´BAL from the integral (W´BALint), differential (W´BALdiff), and locomotor-specific (OG-W´BAL) methods were compared. RESULTS:The relationship between [Formula: see text] and DCP was exponential (r2 = 0.52). The [Formula: see text] for SL, SM, and SH trials were 119 ± 32-s, 190 ± 45-s, and 336 ± 77-s, respectively. Actual TLIM in the 30-15 IFT (968 ± 117-s) compared closely to TLIM predicted by OG-W´BAL (929 ± 94-s, P > 0.100) and W´BALdiff (938 ± 84-s, P > 0.100) but not to W´BALint (848 ± 91-s, P = 0.001). CONCLUSION:The OG-W´BAL accurately tracked W´ kinetics during intermittent running to exhaustion on flat surfaces.
| S-EPMC6969867 | biostudies-literature
Project description:PurposeThe desire-goal motivational conflict helps explain endurance performance; however, the physiological concomitants are unknown. The present study examined disturbances in desire to reduce effort and performance goal value across moderate, heavy, and severe exercise intensity domains, demarcated by the first (LT1) and second (LT2) lactate thresholds. In addition, the within-person relationships among blood lactate concentration, heart rate, and desire-goal conflict were examined.MethodsThirty participants (53% female, Mage = 21.03 years; SD = 2.06 years) completed an incremental cycling exercise test, in which work rate was increased by 25 watts every four minutes, until voluntary exhaustion or sufficient data from the severe intensity domain had been collected. Desire to reduce effort, performance goal value, blood lactate concentration (for determination of LT1 and LT2), and heart rate were measured at the end of each stage and analyzed using multilevel models.ResultsThe desire to reduce effort increased over the exercise test with additional shifts and accelerations after each lactate threshold. The performance goal did not show general declines, nor did it shift at LT1. However, the performance goal value shifted at LT2, and the rate of change increased at both thresholds. Within-person variation in blood lactate concentration positively correlated with the desire to reduce effort and negatively correlated with the performance goal. Within-person variation in heart rate correlated with desire to reduce effort but not the performance goal.ConclusionTransitioning through both lactate thresholds is important phases for motivation during progressive exercise, particularly for the desire to reduce effort. Within-person variation in blood lactate concentration is more influential for motivation, compared with heart rate.
| S-EPMC9305115 | biostudies-literature
Project description:Objective: To create a prediction model of the risk of severe/critical disease in patients with Coronavirus disease (COVID-19). Methods: Clinical, laboratory, and lung computed tomography (CT) severity score were collected from patients admitted for COVID-19 pneumonia and considered as independent variables for the risk of severe/critical disease in a logistic regression analysis. The discriminative properties of the variables were analyzed through the area under the receiver operating characteristic curve analysis and included in a prediction model based on Fagan's nomogram to calculate the post-test probability of severe/critical disease. All analyses were conducted using Medcalc (version 19.0, MedCalc Software, Ostend, Belgium). Results: One hundred seventy-one patients with COVID-19 pneumonia, including 37 severe/critical cases (21.6%) and 134 mild/moderate cases were evaluated. Among all the analyzed variables, Charlson Comorbidity Index (CCI) was that with the highest relative importance (p = 0.0001), followed by CT severity score (p = 0.0002), and age (p = 0.0009). The optimal cut-off points for the predictive variables resulted: 3 for CCI [sensitivity 83.8%, specificity 69.6%, positive likelihood ratio (+LR) 2.76], 69.9 for age (sensitivity 94.6%, specificity 68.1, +LR 2.97), and 53 for CT severity score (sensitivity 64.9%, specificity 84.4%, +LR 4.17). Conclusion: The nomogram including CCI, age, and CT severity score, may be used to stratify patients with COVID-19 pneumonia.
| S-EPMC8456023 | biostudies-literature
Project description:BackgroundThere is a growing interest among the research community and clinical practitioners to investigate cardiopulmonary exercise test (CPET) procedures and protocols utilized in supine cycling.Materials and methodsThe current study investigated the effects of posture on indicators of exercise intensity including gas exchange threshold (GET), respiratory compensation point (RCP), and the rate of peak oxygen uptake (V̇O2 peak), as well as the role of V̇O2 mean response time (MRT) in determining exercise intensity domains in nineteen healthy men (age: 22 ± 3 years). Two moderate-intensity step-transitions from 20 to 100 Watt (W) were completed, followed by a maximal CPET. After completing the ramp test, participants performed a constant-load at 90% of their attained peak power output (PPO).ResultsNo differences were observed in the V̇O2 MRT between the two positions, although the phase II-time constant (τV̇O2p) was 7 s slower in supine position compared to upright (p = 0.001). The rate of O2 uptake in the supine position at GET and RCP were lower compared to the upright position (208 ± 200 mL·min-1 (p = 0.007) and 265 ± 235 mL·min-1 (p = 0.012) respectively). Besides, V̇O2 peak was significantly decreased (by 6%, p = 0.002) during supine position. These findings were confirmed by the wide limits of agreement between the measures of V̇O2 in different postures (V̇O2 peak: -341 to 859; constant-load test: -528 to 783; GET: -375 to 789; RCP: -520 to 1021 all in mL·min-1).ConclusionSince an accurate identification of an appropriate power output (PO) from a single-visit CPET remains a matter of debate, especially for supine cycling, we propose that moderate-intensity step-transitions preceding a ramp CPET could be a viable addition to ensure appropriate exercise-intensity domain determination, in particular upon GET-based prescription.
| S-EPMC9013233 | biostudies-literature
Project description:During heavy and severe constant-load exercise, VO2 displays a slow component (VO2sc) typically interpreted as a loss of efficiency of locomotion. In the ongoing debate on the underpinnings of the VO2sc, recent studies suggested that VO2sc could be attributed to a prolonged shift in energetic sources rather than loss of efficiency. We tested the hypothesis that the total cost of cycling, accounting for aerobic and anaerobic energy sources, is affected by time during metabolic transitions in different intensity domains. Eight active men performed 3 constant load trials of 3, 6, and 9 min in the moderate, heavy, and severe domains (i.e., respectively below, between, and above the two ventilatory thresholds). VO2, VO2 of ventilation and lactate accumulation ([La-]) were quantified to calculate the adjusted oxygen cost of exercise (AdjO2Eq, i.e., measured VO2 - VO2 of ventilation + VO2 equivalent of [La-]) for the 0-3, 3-6, and 6-9 time segments at each intensity, and compared by a two-way RM-ANOVA (time × intensity). After the transient phase, AdjO2Eq was unaffected by time in moderate (ml*3 min-1 at 0-3, 0-6, 0-9 min: 2126 ± 939 < 2687 ± 1036, 2731 ± 1035) and heavy (4278 ± 1074 < 5121 ± 1268, 5225 ± 1123) while a significant effect of time was detected in the severe only (5863 ± 1413 < 7061 ± 1516 < 7372 ± 1443). The emergence of the VO2sc was explained by a prolonged shift between aerobic and anaerobic energy sources in heavy (VO2 - VO2 of ventilation: ml*3 min-1 at 0-3, 0-6, 0-9 min: 3769 ± 1128 < 4938 ± 1256, 5091 ± 1123, [La-]: 452 ± 254 < 128 ± 169, 79 ± 135), while a prolonged metabolic shift and a true loss of efficiency explained the emergence of the VO2sc in severe.
| S-EPMC7476983 | biostudies-literature
Project description:BackgroundHigh-intensity interval training (HIIT) features short, repeated bursts of relatively vigorous exercise with intermittent periods of rest or low-intensity exercise. High-intensity power training (HIPT), in combination with HIIT and traditional resistance training (TRT), is characterized as multijoint high-intensity resistance exercises with low interset rest periods. HIPT requires people to finish the exercise as fast as possible, which increases acute physiological demands. The aim of the study was to investigate the differences between eight-week HIPT or TRT on exercise performance.MethodsTwenty-four college students were recruited and randomly assigned to either the HIPT or TRT group in a counterbalanced order. The power of upper and lower limbs (50% 1RM bench press and vertical jump) and anaerobic power were tested before and after the training (weeks 0 and 9). The results were analyzed by two-way analysis of variance (ANOVA) or Friedman's test with a significance level of α = 0.05 to compare the effects of the intervention on exercise performance.ResultsThere were significant differences in the explosive force of the upper and lower limbs between the pretest and post-test in both the HIPT and TRT groups (p < 0.05). However, only the HIPT group showed a significant difference in the mean power on the Wingate anaerobic test between the pretest and post-test (p < 0.05).ConclusionsBoth HIPT and TRT can improve upper and lower limb explosive force. HIPT is an efficient training protocol, which took less time and produced a better improvement in mean anaerobic power.
| S-EPMC9367759 | biostudies-literature
Project description:Several theoretical frameworks have been used to understand exercise adherence. Basic psychological needs (BPN), grounded on self-determination theory, have received large attention for this purpose. More recently, the hedonic theory and the assumptions related to the exercise characteristics (e.g., intensity) that can bolster positive affective responses have been revitalized. This study aimed to explore the associations between the agreement of current exercise intensity and the one individually preferred, BPN satisfaction/frustration, enjoyment, the intention to continue exercise, and exercise frequency. Additionally, an exploration of the direct and indirect effects while testing sex as a moderator was performed. A sample of 369 exercisers (Mage = 43.6, standard deviation = 12.96; 214 females) enrolled in 26 health clubs participated in this study voluntarily. Data were received in a first-approach descriptive and correlational analyses. Next, a moderated mediation was performed using model 15 (PROCESS v.4.2). As a result, agreement in preference for exercise intensity was positively associated with enjoyment (r = 0.35), intention (r = 0.43), and all needs satisfaction (ranging from r = 0.12 to r = 0.45) and negatively associated with all needs frustration (ranging from r = -0.15 to r = -0.31). In the moderated mediation analysis, the same pattern of results emerged in direct effects. Indirect effects were significant for autonomy in the enjoyment and frequency models. Findings suggest that promoting an individually adjusted training intensity may foster BPN satisfaction. It appears to be present an independent (of needs) and positive association with exercise enjoyment and intention to continue exercising.
| S-EPMC11451574 | biostudies-literature
Project description:IntroductionFatigue is one of the most disabling symptoms in COPD, but little is known about the impact of fatigue on functional disability. We explored the impact of fatigue and fatigue intensity on exercise tolerance after adjusting for other factors using multivariate analysis and compared it to that of dyspnoea.MethodsA total of 119 patients with mainly moderate-severe stable COPD (38 % women, mean age 66 years) were enrolled. We used the Medical Research Council dyspnoea scores (MRC), Manchester COPD fatigue scale (MCFS) and its three dimensions, Borg scales for fatigue and dyspnoea, six-minute walk distance (6MWD), St George's Respiratory Questionnaire, the BODE index, and the Centre for Epidemiological Study on Depression scale (CES-D), and we measured spirometry, blood gases, systemic inflammatory markers and fat-free mass index (FFMI).ResultsFatigue measured using the MCFS was associated with 6MWD and explained 22 % of the variability in 6MWD (p < 0.001). Fatigue remained associated with 6MWD after adjusting for MRC dyspnoea, FFMI and FEV1, FVC, PaO2, PaCO2, CES-D, TNF-alpha, smoking status, age and gender. We found that 33, 50 and 23 % of patients reported an increase by 2 scores on Borg scales for fatigue, dyspnoea or both at the end of the 6MWT. Fatigue scores (both before and after the 6MWT) were negatively correlated with 6MWD after adjusting for FEV1, FFMI, CES-D score and age (p = 0.007 and 0.001, respectively).ConclusionIn moderate stable COPD, fatigue may be a central driver of functional disability, to the same extent as dyspnoea.
| S-EPMC5093188 | biostudies-literature