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The purpose of this study was to determine the effects of the simultaneous use of pyridoxine-alpha-ketoglutarate (PAK) and sodium bicarbonate (NaHCO3) on short-term maximal exercise capacity in eight well-trained male cyclists. The study consisted of the determination of maximal power output and the administration of various combinations of placebos, PAK and NaHCO3, followed by a short-term maximal exercise test. To determine maximal power output (power(max)), the subjects performed a continuous, incremental test on a Monark bicycle ergometer to symptom limited maximum (test 1). To determine the effects of NaHCO3 and PAK on short-term maximal exercise performance, the subjects were administered either placebo (PLA), PAK and sodium bicarbonate (P/B), PAK and placebo (PAK), or sodium bicarbonate and placebo (BIC) prior to performing short-term maximal exercise (test 2). Oral tablets of NaHCO3 and PAK were given in doses of 200 mg kg-1 and 50 mg kg-1 respectively. The subjects pedalled at the power output corresponding to 100% of their VO2 max at 70 rev min-1 until voluntary cessation or until they were unable to maintain pedal revolution rate. Venous blood samples were drawn at rest (RES), cessation of exercise (CES) and after 2 min of recovery (REC) and analysed for lactate, pH and bicarbonate ion concentration. The subjects attained an average maximum power output of 377 +/- 20 W during the graded maximal pre-test (test 1). There were no significant differences between treatments in the ability to sustain power(max) during test 2. During test 2, the subjects were able to sustain power(max) for 7.6 +/- 4.3 min with P/B, 6.7 +/- 2.9 min with PAK, 7.3 +/- 4.9 min with BIC and 6.9 +/- 2.7 min with placebo (mean +/- S.E.). Blood lactate (BLa) was significantly elevated at cessation of exercise and remained elevated during recovery, but there were no significant differences between treatments. Bicarbonate fell significantly during exercise and recovery in each treatment. At rest, bicarbonate levels were significantly higher in both the P/B and BIC than in the PAK or PLA treatments. Pooled data from the P/B and BIC treatments demonstrated a significant increase in pH at rest and end of exercise when compared to PLA treatment. These data suggest that sodium bicarbonate rather than PAK was responsible for this increase. In summary, our data suggest that in the dosages used in this study, administration of sodium bicarbonate or PAK, alone or in combination, is ineffective in increasing short-term maximal exercise capacity. 相似文献
43.
Alex Kesselman Kirill Kogan Michael Segal 《Informatik - Forschung und Entwicklung》2006,23(3):238-240
Informatik-Patente
Informatik-Patente 相似文献44.
Debbi Weaver Diane Robbie Alex Radloff 《International Journal for Academic Development》2013,18(3):212-225
This paper reports on a writing program to support academic staff to publish in peer-refereed journals. Nine participants completed a 12-week program, which involved regular meetings, set writing tasks, and peer feedback on drafts. A pre- and post-survey and follow-up interviews were used to gather feedback. Participants especially valued the discipline of weekly sessions and peer feedback. They reported increased skills and confidence in their writing, greater knowledge of the publication process, and intention to continue writing. Although five papers were published, a 12-month follow-up revealed that original writing intentions were not sustained. Thus, while a structured writing program can be effective, the pressures academic staff experience trying to meet conflicting requirements of teaching, administration, and research, must also be addressed. 相似文献
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Gustavo Leporace Marcio Tannure Gabriel Zeitoune Leonardo Metsavaht Moacir Marocolo Alex Souto Maior 《Sports biomechanics / International Society of Biomechanics in Sports》2020,19(3):411-420
AbstractThe aim of this study was to test the correlation between knee-to-hip flexion ratio during a single leg landing task and hip and knee strength, and ankle range of motion. Twenty-four male participants from a professional soccer team performed a continuous single leg jump-landing test during 10s, while lower limb kinematics data were collected using a motion analysis system. After biomechanical testing, maximal isometric hip (abduction, extension, external rotation), knee extension and flexion strength were measured. Maximum ankle dorsiflexion range of motion was assessed statically using the weight bearing lunge test. Pearson correlation coefficients were calculated to determine the associations between the predictor variables (knee and hip strength, and ankle ROM) and the main outcome measure (knee-to-hip flexion ratio). Correlation between knee-to-hip flexion ratio and hip abductors strength was significant (r = ?0.47; p = 0.019). No other significant correlations were observed among the variables (p > 0.05). These results demonstrated that a lower hip abductors strength in male soccer players was correlated with a high knee-to-hip flexion ratio during landing from a single leg jump, potentially increasing knee overload by decreasing energy absorption at the hip. The results provide a novel proposal for the functioning of hip muscles to control knee overload. 相似文献
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As university libraries transition to digital collections and new services, their book deselection projects often lead to the adoption of cross-discipline quantitative weeding criteria (such as age and low circulation) in the interest of speed and presumed fairness. Cross-discipline quantitative rubrics, however, can have unintended negative consequences when applied to disciplines such as history and literature that rely on older books with low circulation statistics. The authors argue for a discipline-differentiated approach to weeding academic library collections that can employ quantitative criteria for disciplines, such as in the sciences, that are more reliant on current materials and qualitative criteria for disciplines, such as in the humanities, whose scholars benefit from ready access to older and low-use books. 相似文献
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Key points
- Twenty years ago, a fraction of articles were paired with supplements; now, one in five research stories go beyond PDF.
- Why has the evolution of research content's delivery vehicles lagged behind the evolution of the research story?
- Hyperlinked in‐line references are the most used feature of the Enhanced PDF – exposing faster, easier ways to follow the path of research.
- Discovery need not start and end with the search engine – it can start within the PDF itself.
- Discovery is not a solitary process; therefore, content platforms must support collaboration to drive readership.