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Stability of pedalling mechanics during a prolonged cycling exercise performed at different cadences
The aim of this study was to analyse the effect of pedalling rate on the pattern of mechanical torque application and on neuromuscular fatigue during prolonged cycling exercise. Eleven well-trained individuals performed three 1-h pedalling sessions, at 50 rev.min-1, 110 rev.min-1 and a freely chosen cadence, at an intensity corresponding to 65% of their maximal aerobic power. The mechanical torque applied on the right pedal was recorded for 30 s every 5 min while pedalling. Contractile and neural properties of the quadriceps and hamstring muscles were analysed before and immediately after each of the three pedalling sessions. The post-exercise reduction in knee extensors maximal voluntary contraction was significant (P<0.01) irrespective of the cadence, but no difference was found between cadences. The use of a particular cadence did not lead to preferentially central or peripheral fatigue. An increase in cadence resulted in greater positive and negative work generated during pedalling. The mechanical pattern was not altered during the exercise, whatever the selected cadence. The present study demonstrates that despite the occurrence of neuromuscular fatigue, trained individuals maintained a stable pedalling pattern throughout an endurance cycling exercise for cadences ranging from 50 to 110 rev.min-1. 相似文献
125.
Jeroen A. van Kan Ce Zhang Piravi Perumal Malar Johan R. C. van der Maarel 《Biomicrofluidics》2012,6(3)
An easy method is introduced allowing fast polydimethylsiloxane (PDMS) replication of nanofluidic lab-on-chip devices using accurately fabricated molds featuring cross-sections down to 60 nm. A high quality master is obtained through proton beam writing and UV lithography. This master can be used more than 200 times to replicate nanofluidic devices capable of handling single DNA molecules. This method allows to fabricate nanofluidic devices through simple PDMS casting. The extensions of YOYO-1 stained bacteriophage T4 and λ−DNA inside these nanochannels have been investigated using fluorescence microscopy and follow the scaling prediction of a large, locally coiled polymer chain confined in nanochannels. 相似文献
126.
In this study we investigated if the occurrence of the sticking region was a result of diminishing potentiation (coinciding delayed muscle activation) or the result of a mechanically poor region in which the muscles can produce less force. A regular one-repetition maximum (1RM) free-weight bench press was compared with isometric bench presses performed at 12 different positions. A lower force at the sticking region compared to the other regions in the isometric bench presses would confirm the mechanically-poor-position hypothesis. Twelve resistance-trained males (age 21.7 ± 1.3 years, mass 78 ± 5.8 kg, height 1.81 ± 0.05 m) were tested in 1RM and in isometric contractions in bench press in 12 different positions, indicated by the vertical distance between barbell and sternum, covering the whole range of motion during the concentric phase. Barbell kinematics and muscle activity were registered. In both types of executions a region of lower force output was observed, which supports the mechanically-poor-position hypothesis. Electromyographic activity of four muscles showed the same pattern in the isometric and 1RM attempts. It was concluded that diminishing effect potentiation could not explain the existence of the sticking region. 相似文献
127.
Empirical data on the development of interaction, communication, and language in deafblind children is very rare. To fill this gap, a case study was conducted in which the interaction between a teacher and a deafblind boy age 3 years 4 months was analyzed. Sequential analysis of their interaction confirmed some general clinical impressions about interaction with deafblind children, and provided the basis for suggestions on how the interaction pattern might be changed. 相似文献
128.
Lexical-decision studies with experienced English and French readers have shown that visual-word identification is not only
affected by pronunciation inconsistency of a word (i.e., multiple ways to pronounce a spelling body), but also by spelling
inconsistency (i.e., multiple ways to spell a pronunciation rime). The aim of this study was to compare the reading behavior
of young Dutch readers with dyslexia to the behavior of readers without dyslexia. All students participated in a lexical-decision
task in which we presented pronunciation-consistent words and pseudowords. Half of the pronunciation-consistent stimuli were
spelling consistent and the other half were spelling inconsistent. All three reader groups, that is, students with dyslexia,
age-match students, and reading-match students, read spelling-consistent words faster than spelling-inconsistent words. Overall
reading speed of students with dyslexia was similar to that of reading-match students, and was substantially slower than that
of age-match students. The results suggest that reading in students with or without dyslexia is similarly affected by spelling
inconsistency. Subtle qualitative differences emerged, however, with respect to pseudoword identification. The conclusion
was that the findings were best interpreted in terms of a recurrent-feedback model. 相似文献
129.
BACKGROUND: The National Library for Health offers a comprehensive searchable database of nationally approved clinical guidelines, called the Guidelines Finder. This resource, commissioned in 2002, is managed and developed by the University of Sheffield Health Sciences Library. METHODS: The authors introduce the historical and political dimension of guidelines and the nature of guidelines as a mechanism to ensure clinical effectiveness in practice. The article then outlines the maintenance and organisation of the Guidelines Finder database itself, the criteria for selection, who publishes guidelines and guideline formats, usage of the Guidelines Finder service and finally looks at some lessons learnt from a local library offering a national service. CONCLUSIONS: Clinical guidelines are central to effective clinical practice at the national, organisational and individual level. The Guidelines Finder is one of the most visited resources within the National Library for Health and is successful in answering information needs related to specific patient care, clinical research, guideline development and education. 相似文献
130.
Anthony F.J. van Raan Thed N. van Leeuwen Martijn S. Visser Nees Jan van Eck Ludo Waltman 《Journal of Informetrics》2010,4(3):431-435
We reply to the criticism of Opthof and Leydesdorff on the way in which our institute applies journal and field normalizations to citation counts. We point out why we believe most of the criticism is unjustified, but we also indicate where we think Opthof and Leydesdorff raise a valid point. 相似文献