Search results for "Preload"
showing 10 items of 21 documents
Including the Past: Performance Modeling Using a Preload Concept by Means of the Fitness-Fatigue Model
2019
Abstract In mathematical modeling by means of performance models, the Fitness-Fatigue Model (FF-Model) is a common approach in sport and exercise science to study the training performance relationship. The FF-Model uses an initial basic level of performance and two antagonistic terms (for fitness and fatigue). By model calibration, parameters are adapted to the subject’s individual physical response to training load. Although the simulation of the recorded training data in most cases shows useful results when the model is calibrated and all parameters are adjusted, this method has two major difficulties. First, a fitted value as basic performance will usually be too high. Second, without mo…
11 and 15-month-old infants do not compensate immediately for energy variation, and no further adjustment occurs 12 or 24 hours later
2021
International audience; Previously, we demonstrated that, in the short term, infants undercompensated for the energy from a preload given 25 min before an ad libitum meal. However, although not consistent, there is evidence in young children that caloric adjustment may occur over longer periods. We investigated the extent to which further energy adjustment occurs up to 24 h after a single meal preceded by preloads of varying energy density (ED) in infants that are 11 and 15 months old. Short-term caloric adjustment was measured in 11- and 15-month-old infants through a preload paradigm meal in the laboratory. To assess their caloric adjustment over longer periods (12 and 24 h), we used 24 h…
Impact of adiposity, age, sex and maternal feeding practices on eating in the absence of hunger and caloric compensation in preschool children
2015
BACKGROUND/OBJECTIVES: Between the ages of 3 and 5 years, children may become less responsive to internal cues of satiation and more responsive to external cues, which may induce overeating and lead to weight gain. This study aimed to compare eating in the absence of hunger (EAH) and caloric compensation in 3- to 6-year-old children, and to relate the measurements with children's adiposity, age, sex and maternal feeding practices. METHODS: According to a within-subject three sequential condition design, food intake in children (n=236) was measured at lunch during three sessions, once a week. The same meal (565 kcal) was offered at each session. The first session (control) was only composed …
Left ventricular function after acute myocardial infarction
1976
10 patients with their first AMI were studied within the first 48 hours and again after 3 weeks. Central and peripheral haemodynamics (CI, SV, SW, TPR) were examined, including indices of contractility (dp/dtmax) and wall stiffness (deltaP/deltaV, relation deltaP/deltaV to P) of the left ventricle. In the early phase CI and SW, as well as LV dp/dtmax were depressed in accordance with symptoms of LV failure. deltaP/deltaV was increased. Elevation of LVEDP correlated well with ventricular gallop rhythm, but less consistently with LV functional disturbance. During convalescence CI increased uniformly, both in digitalized and non-digitalized individuals. In contrast heart rate, aortic pressure,…
Experimental investigation on the compressive behavior of short-term preloaded carbon fiber reinforced polymer-confined concrete columns
2017
Strengthening of concrete columns with fiber reinforced polymer sheets provides a good improvement to the existing structural members in terms of load and strain capacity due to the properties of the composite jacket. A proper knowledge of the load–strain response of the composite members is necessary to design retrofitting intervention of existing structures; however, so far the available design methods do not allow to take into account the effect of the possible presence of service loads on the compressive behavior of the reinforced columns. An experimental investigation on the compressive behavior of preloaded circular concrete columns reinforced with carbon fiber reinforced polymer was …
Beta-receptor desensitization evoked by a multistage ultralong distance exercise in the desert?
2021
Background Few studies addressed to the evolution of cardiac function during a multistage ultra-long duration exercise (MULDE). Methods Serial echocardiographic assessment of cardiac function was performed in male healthy subjects during the 2014 Marathon des Sables before the race (T1), at the second (T2) and fifth (T3) arrival (236 km) then after 48 h recovery. Analysis were performed by 2 sonographers blind for the results of the other and the time of measure. Statistical analysis was performed using ANOVA-RM to compare the evolution of the different parameters. Results Among the 20 athletes, 18 completed the study (mean age 42.4, median 42). RR intervals and (Left ventricular End Diasto…
In vitro cardiac performance in the sub-antarctic notothenioids Eleginops maclovinus (subfamily eleginopinae), Paranotothenia magellanica, and Patago…
1997
There is lack of information concerning species diversification in the Non-Antarctic Nototheniid fish both in relation with their variation in organismal performance and in the morphofunctional characteristics underlying this variation. This work was designed to study in three Sub-Antarctic Nototheniids, Eleginops maclovinus, Patagonotothen tessellata, and Paranotothenia magellanica, cardiocirculatory features that may reflect interspecific differences in organismal performance, which in rum may explain aspects of evolutionary and ecological diversity. Haematocrit values were similar in all three species (between 28 and 3?), being in the range of that observed in other red-blooded Nototheni…
A Fiber Optic Strain Gage Sensor for Measuring Preload in Thick Composite Bolted Joints
2019
Mechanical fastening is a popular choice in joining composites because of the ability to transfer high loads and the ease of assembly and disassembly. In this study, the failure behavior of composite–aluminum single lap bolted joint is investigated. In particular, the effects of varying the preload on the bolt are examined. In order to accurately measure the preload, a specialized sensor that uses a fiber Bragg grating sensor embedded in the bolt is proposed and created. This sensor is realized for the current tests but can be expanded to other applications. An experimental study of bolted single-lap joints varying the tightening torque value has been carried out and, in order to validate t…
Compressive response of substandard steel-jacketed RC columns strengthened under sustained service loads: From the local to the global behavior
2018
Abstract This paper presents an experimental investigation on substandard partially steel jacketed RC columns strengthened under sustained loads and loaded until failure. The aim of the study is to compare the compressive response of preloaded columns with respect to the tests without preload to obtain a more realistic prediction of load-carrying capacity of structural columns after retrofitting under serviceability loads. The influence of the preload level, the delayed contribution of the confining device during the loading process and the time dependent effects are highlighted for the tested specimens. Based on the experimental observations, an analysis-oriented model is proposed for the …
Influence of preload and afterload on stroke volume response to low-dose dobutamine stress in patients with non-ischemic heart failure: a cardiac MR …
2011
Lack of increase in left ventricular (LV) stroke volume (SV) during low-dose dobutamine stress (LDD) is attributed to exhausted cardiac contractile reserve in failing heart. However, the role of the afterload and preload in SV changes is underestimated. The aim of the study was to investigate the effects of LDD on preload reserve and afterload in patients with non-ischemic heart failure.58 patients (age 62 years) underwent LDD (up to 20μg/kg/min) using cardiac magnetic resonance.LV-SV increased by 27% in 24 patients (p0.001) (SV+), while decreased by 19% in 22 patients (p0.001) (SV-). The LDD-to-rest reduction in preload, as defined by LV end-diastolic volume (EDV), was more pronounced in S…