Search results for "Eccentric"
showing 10 items of 182 documents
Feasibility, safety and muscle activity during flywheel vs traditional strength training in adult patients with severe haemophilia
2021
INTRODUCTION: Eccentric training has been associated with several specific physiological adaptations. The flywheel machine is one of the easiest ways of performing eccentric overload training. However, no studies evaluated its feasibility, safety and muscle activity in patients with haemophilia (PWH).AIM: To evaluate feasibility and safety and compare muscle activity during flywheel vs weight machine knee extension exercise in severe PWH.METHODS: Eleven severe PWH [mean age of 33.5 (8.1) years] participated in this cross-sectional study after receiving prophylactic treatment. Surface electromyography (EMG) signals were recorded for the rectus femoris during the knee extension exercise perfo…
Velocity-specific training in elbow flexors.
1999
The purpose of this study was to show that velocity-specific training may be implicated in modifications in the level of coactivation of agonist and antagonist muscles. Healthy males (n = 20) were randomly placed in to two groups: one group trained using concentric contractions (n = 12), the other was an untrained control group (n = 8). The training group underwent unilateral resistance training at a level of 35 (5)% of a one-repetition maximal contraction of the elbow flexors, executed at maximal angular velocity. Training sessions consisted of six sets of eight consecutive elbow flexions, three times per weak for a total of seven weeks. The velocity of the ballistic movements executed dur…
Astrochronology of the Valanginian stage from GSSP candidates and hypostratotype.
2013
Valanginian; Astrochronology; Gamma-ray spectrometry; Weissert event; Paraná-Etendeka; International audience; The Valanginian Stage currently displays no radiometric age, which severely hampers palaeoceanographic reconstructions for this time interval. An astrochronology of the Valanginian Stage using the stable 405-kyr eccentricity cycle was performed on biostratigraphically well-calibrated standard sections from the Vocontian Basin (southeastern France). High-resolution gamma-ray spectrometry signals were obtained from orbitally driven marl-limestone alternations from five sections in the basin, and they display the same long-term trends. The spectral analyses present the pervasive recor…
Search for eccentric binary black hole mergers with advanced LIGO and advanced Virgo during their first and second observing runs
2019
When formed through dynamical interactions, stellar-mass binary black holes may retain eccentric orbits ($e>0.1$ at 10 Hz) detectable by ground-based gravitational-wave detectors. Eccentricity can therefore be used to differentiate dynamically-formed binaries from isolated binary black hole mergers. Current template-based gravitational-wave searches do not use waveform models associated to eccentric orbits, rendering the search less efficient to eccentric binary systems. Here we present results of a search for binary black hole mergers that inspiral in eccentric orbits using data from the first and second observing runs (O1 and O2) of Advanced LIGO and Advanced Virgo. The search uses min…
Spectroscopic Observations of the Delta Scorpii Binary during Its Recent Periastron Passage
2001
The bright star delta Sco has been considered a typical B0-type object for many years. Spectra of the star published prior to 1990 showed no evidence of emission, but only of short-term line profile variations attributed to nonradial pulsations. Speckle interferometric observations show that delta Sco is a binary system with a highly-eccentric orbit and a period of 10.6 years. Weak emission in the H-alpha line was detected in its spectrum for the first time during a periastron passage in 1990. Shortly before the next periastron passage in the summer of 2000, the binary entered a strong H-alpha emission and enhanced mass loss phase. We monitored the spectroscopic development of the Be outbur…
Shape indices to identify regional differences in otolith morphology of comber, Serranus cabrilla (L., 1758)
2003
Summary Sagittal otoliths from the Atlantic and Mediterranean regions of Serranus cabrilla L. were compared using shape indices (form-factor, roundness, circularity, rectangularity, ellipticity and eccentricity). Regional differences were best described by form-factor, circularity and eccentricity variables. The canonical discriminant functions were built with form-factor or rectangularity indices. The results indicated slight regional variations. The G-test was the criterion more useful to identify the otolith origin in the discriminant analysis.
Altérations neuromusculaires induites par des exercices excentriques et concentriques fatigants : emphase sur le pédalage des membres inférieurs
2021
The influence of dynamic contraction type (concentric or eccentric) on performance fatigability and associated neuromuscular alterations is partly unknown. Contraction type interacts with other exercise features such as intensity (maximal; submaximal) or modality (single-joint; locomotor). Thus, we compared eccentric with concentric exercises of similar characteristics across three experimental studies. We showed that, for the completion of a given amount of mechanical work, both contraction types impaired maximal voluntary isometric torque similarly. However, neuromuscular impairments depended on exercise features. In study 1, maximal single-joint eccentric contractions affected neural but…
Influence of the muscle mode of contraction on the exercise induced neuroplastic effects
2018
Along with cardiovascular and neuromuscular changes, mono-articular and locomotor exercises may induced neuroplastic changes from muscles involved, or non-involved, in the exercise. If the effect of exercise intensity or duration on neuroplastic changes has been previously investigated, the effect of the mode of muscle contraction remains unclear. The aim of this thesis was to investigate the effects of the mode of muscle contraction on neuroplastic changes induced a locomotor or a single-joint exercise. The first study showed that the increase in the corticospinal excitability of a non-exercised hand muscle, observed after a walking/ running exercise, was not modulated by the knee extensor…
Osmium and lithium isotope evidence for weathering feedbacks linked to orbitally paced organic carbon burial and Silurian glaciations
2022
Abstract The Ordovician (∼487 to 443 Ma) ended with the formation of extensive Southern Hemisphere ice sheets, known as the Hirnantian glaciation, and the second largest mass extinction in Earth History. It was followed by the Silurian (∼443 to 419 Ma), one of the most climatically unstable periods of the Phanerozoic as evidenced by several large scale ( > 5 ‰ ) carbon isotope (δ13C) perturbations associated with further extinction events. Despite several decades of research, the cause of these environmental instabilities remains enigmatic. Here, we provide osmium (187Os/188Os) and lithium (δ7Li) isotope measurements of marine sedimentary rocks that cover four Silurian δ13C excursions. Osmi…
Photothermoelastic analysis of thermal stresses in discs with eccentric holes
1970
The paper deals with thermal stresses that arise in discs with eccentric holes, such as are employed in the rotors of multi-stage gas turbines. The stress distribution was analysed by the photothermoelastic method. CR 39 sheets were used as the material and dry ice as the refrigerant. The effect of several geometric parameters on stress distribution, especially the influence of adjacent holes, was investigated by testing 32 configurations of discs. Curves that allow the determination of the peak stresses and optimum spacing of holes are given.