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Lewis A. Gough Sanjoy K. Deb Danny Brown S. Andy Sparks Lars R. McNaughton 《Journal of sports sciences》2019,37(13):1464-1471
This study investigated the effects of two separate doses of sodium bicarbonate (NaHCO3) on 4 km time trial (TT) cycling performance and post-exercise acid base balance recovery in hypoxia. Fourteen club-level cyclists completed four cycling TT’s, followed by a 40 min passive recovery in normobaric hypoxic conditions (FiO2 = 14.5%) following one of either: two doses of NaHCO3 (0.2 g.kg?1 BM; SBC2, or 0.3 g.kg?1 BM; SBC3), a taste-matched placebo (0.07 g.kg?1 BM sodium chloride; PLA), or a control trial in a double-blind, randomized, repeated-measures and crossover design study. Compared to PLA, TT performance was improved following SBC2 (p = 0.04, g = 0.16, very likely beneficial), but was improved to a greater extent following SBC3 (p = 0.01, g = 0.24, very likely beneficial). Furthermore, a likely benefit of ingesting SBC3 over SBC2 was observed (p = 0.13, g = 0.10), although there was a large inter-individual variation. Both SBC treatments achieved full recovery within 40 min, which was not observed in either PLA or CON following the TT. In conclusion, NaHCO3 improves 4 km TT performance and acid base balance recovery in acute moderate hypoxic conditions, however the optimal dose warrants an individual approach. 相似文献
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Analysis of ATPase characterized type I and type II fibres from biopsy samples of the vastus lateralis muscle of four male subjects showed a selective distribution of carnosine and free taurine similar to that observed in other species. The mean carnosine concentration was twice as high in type II compared with type I muscle fibres (23.2 +/- 17.8 and 10.5 +/- 7.6 mmol . kg -1 dry weight, respectively), while taurine was four times higher in type I compared with type II muscle fibres (39.2 +/- 17.8 and 9.6 +/- 2.6 mmol . kg -1 dw, respectively). Overlap in the concentration of carnosine or taurine between fibre types occurred only once in one subject. There was no overlap between fibre types in the ratio of carnosine to taurine. Higher carnosine concentrations in type II fibres will result in a greater contribution to the buffering of H+ arising from anaerobic metabolism. The contribution in a type II fibre with the highest carnosine content was estimated to equal 28% of that from other sources. 相似文献
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基于VC~（＋＋）的飞机模拟负载自动管理系统设计 总被引：1，自引：0，他引：1
设计的模拟负载自动管理系统可以根据试验技术要求,自动加载不同的负载,实时显示三相电压、三相电流、功率、频率、功率因数、工作时间以及发电机转速。在VC＋＋中引入多线程技术和双缓冲技术,实现了三相电压调制包络线的绘制。编写了峰值测量模块、5小时延时模块、频率采集模块、功率因数测量模块、谐波测量模块等,实现了各参数的准确测量。采用ADO＋SQL Sever技术实现了数据库读写,并在局域网内实现了从机对主机数据库的访问。 相似文献
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Lewis A. Gough Sanjoy K. Deb S. Andy Sparks Lars R. McNaughton 《Journal of sports sciences》2018,36(15):1705-1712
The aim of this study was to investigate the effects of sodium bicarbonate (NaHCO3) on 4 km cycling time trial (TT) performance when individualised to a predetermined time to peak blood bicarbonate (HCO3?). Eleven male trained cyclists volunteered for this study (height 1.82 ± 0.80 m, body mass (BM) 86.4 ± 12.9 kg, age 32 ± 9 years, peak power output (PPO) 382 ± 22 W). Two trials were initially conducted to identify time to peak HCO3? following both 0.2 g.kg?1 BM (SBC2) and 0.3 g.kg?1 BM (SBC3) NaHCO3. Thereafter, on three separate occasions using a randomised, double-blind, crossover design, participants completed a 4 km TT following ingestion of either SBC2, SBC3, or a taste-matched placebo (PLA) containing 0.07 g.kg?1 BM sodium chloride (NaCl) at the predetermined individual time to peak HCO3?. Both SBC2 (?8.3 ± 3.5 s; p < 0.001, d = 0.64) and SBC3 (?8.6 ± 5.4 s; p = 0.003, d = 0.66) reduced the time to complete the 4 km TT, with no difference between SBC conditions (mean difference = 0.2 ± 0.2 s; p = 0.87, d = 0.02). These findings suggest trained cyclists may benefit from individualising NaHCO3 ingestion to time to peak HCO3? to enhance 4 km TT performance. 相似文献
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浅谈防止跳远落地时前冲与后坐的措施 总被引：2，自引：1，他引：1
跳远落地缓冲动作分为三种类型,即链型缓冲、弹性缓冲、刚性缓冲。链型缓冲的缓冲力发生在缓冲阶段后期,水平速度损失大,前冲力小,易出现后坐现象,弹性缓冲的缓冲力发生在缓冲阶段全过程,前冲力和后坐力适中。刚性缓冲冲击力发生在缓冲阶段前期,垂直速度损失大,前冲力大,后坐力小,易出现前冲。冲击类型与落地前准备姿式有关,根据准备姿式选择缓冲类型既有利于提高成绩,又有利于防止落地受伤。 相似文献
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对短跑的动力来源问题、缓冲时相问题、缓冲距离问题等关键性的特点问题进行探讨与分析,从生物力学的角度短跑着地缓冲的动作进行分析,并探究了影响着地缓冲的若干因素,以期完善人们对该动作的认识,服务训练。 相似文献
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描述了一种基于GDI＋的医学图像分析系统的设计原理,实现了眼底图像的缩放、移动、分析、保存与图像增强。系统采用双缓冲技术解决绘图过程中屏幕的闪烁问题,基于颜色矩阵以及GDI＋与GDI混合编程的方法,完成了二维医学图像的处理与分析。最后针对医疗诊断报告单的要求,完成了基于word的文档自动生成与保存。测试表明,该系统运行稳定,效果良好。 相似文献
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