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For the athlete training hard, nutritional supplements are often seen as promoting adaptations to training, allowing more consistent and intensive training by promoting recovery between training sessions, reducing interruptions to training because of illness or injury, and enhancing competitive performance. Surveys show that the prevalence of supplement use is widespread among sportsmen and women, but the use of few of these products is supported by a sound research base and some may even be harmful to the athlete. Special sports foods, including energy bars and sports drinks, have a real role to play, and some protein supplements and meal replacements may also be useful in some circumstances. Where there is a demonstrated deficiency of an essential nutrient, an increased intake from food or from supplementation may help, but many athletes ignore the need for caution in supplement use and take supplements in doses that are not necessary or may even be harmful. Some supplements do offer the prospect of improved performance; these include creatine, caffeine, bicarbonate and, perhaps, a very few others. There is no evidence that prohormones such as androstenedione are effective in enhancing muscle mass or strength, and these prohormones may result in negative health consequences, as well as positive drug tests. Contamination of supplements that may cause an athlete to fail a doping test is widespread. 相似文献
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L-肉毒碱对足球运动员训练过程中生理机能的影响研究 总被引：11，自引：0，他引：11
以足球专项大学生为对象,采用双盲法分别口服Ｌ－肉毒碱和安慰剂３０天,观察训练前后身体机能及运动能力的变化。结果显示：大强度运动训练后对照组各项有氧能力指标均显著下降,呈明显的疲劳状态,而实验组最大摄氧量仍保持原水平,通气阈略上升,尤其是代表单纯有氧能力的通气阈时作功显著增大。研究表明,实验组有氧能力的改善主要是由于组织内脂肪供能的加强所致,而适当补充Ｌ－肉毒碱可能正是改善脂肪代谢的关键。 相似文献
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目的：探讨大鼠睾丸扭转2h和5h复位后24h附睾肉毒碱含量的变化及意义．方法：24只成年健康雄性SD大鼠随机分为3组，建立左侧睾丸扭转复位模型：对照组、A组（扭转2h）和B组（扭转5h）．DTNB法检测扭转侧附睾肉毒碱的含量．结果：睾丸扭转2h复位后24h，扭转侧附睾上肉毒碱含量改变不明显（P〉0.05）；扭转5h复位后24h，扭转侧附睾肉毒碱含量下降明显（P〈0．05）．结论：睾丸扭转2h复位后24h，附睾浓缩分泌肉毒碱的功能不受影响；扭转5h复位后24h，附睾浓缩分泌肉毒碱的功能下降． 相似文献
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肉碱对玉米生长及产量的影响 总被引：1，自引：0，他引：1
用肉碱处理唐抗5号玉米种子,结果表明:肉碱可以提高苗期的光和强度;植株高度、穗位高度显著增加;茎加粗,穗长、穗粗和穗粒重比对照增加;从而增加了单位面积玉米产量,提高了经济效益. 相似文献
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丙酮酸或丙酮酸-肉碱补充对定量负荷运动时脂肪动用和RPE的影响 总被引：6，自引：0，他引：6
本研究通过观察定量负待运动前后血液中自由脂肪酸、血糖和乳酸水平的变化及运动中RQ和RPE的变化，研究丙酮改补充对机体有氧运动时脂肪动用和主观感觉疲劳的影响及肉碱对此的作用，探讨丙酮酸—肉碱复合剂的应用价值。结果：与安慰剂组相比，2试验组的FFA水平较高；除定量负荷运动30mi时外，丙酮酸组在安静时，定量负荷运动15min时的RQ较低，复合剂组在各种条件下的RQ均较低，2试验组运动中RPE较低，均有显著性意义。结论：丙酮酸补充能促进有氧运动中脂肪的动员，但对有氧运动中脂肪利用的影响不大；复合剂能同时促进有氧运动中脂肪的动员和利用；丙酮酸和复合剂能改善有氧运动时的主观感觉疲劳状态；复合剂对体重控制有一定的应用价值。 相似文献
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为了研究肉碱棕榈酰转移酶(CPT-1β)基因区的rs 131758、rs 470117多态位点以及由其组成的单体型与有氧耐力训练前后敏感性指标的变化之间的关联性,探讨其作为有氧耐力训练敏感性标记的可行性,对102名中国北方汉族青年进行为期18周的有氧耐力训练。采用活动跑台的逐级递增运动负荷方法测定训练前后"跑节省化"(RE)相关指标;采用卧式蹬车的极限下递增定量负荷运动方式测定训练前后不同负荷状态下(安静时、50 W、100 W、150 W、恢复期)的心脏结构指标;由心脏结构指标获得心脏功能相关指标。采用MALDI-TOF MS方法解析受试者基因组DNA rs 131758、rs 470117多态位点基因型。分析训练前后相关指标的变化与多态位点不同基因型之间的关联性。结果发现:1)rs 131758位点的AA型与训练后跑节省化时心率(ΔHRRE)的训练敏感性相关联;2)rs131758位点的AA型与训练后心脏收缩末期左室后壁厚度ΔPWS指标的训练敏感性相关联;3)由rs 131758-rs 470117位点组成的单体型AT与训练后安静时每搏输出量指数(ΔSVI)、心动周期(ΔT)、心输出量指数(ΔCOI)的训练敏感性相关联。说明:rs 131758位点的AA型和由rs131758-rs470117位点组成的AT单体型可以作为中国北方汉族人群对有氧耐力训练敏感的分子标记。 相似文献
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通过文献资料法、逻辑分析法对部分女大学生的全素食行为进行分析,发现绝对的素食的女大学生出现种种不适,呈现亚健康状态;同时正常的生理机能受到损伤,在一定强度的有氧运动时,运动能力明显低于非素食者。左旋肉碱是减脂的必需辅酶,红肉是左旋肉碱的主要食物来源。绝对食素不利于健康,要在学生当中大力宣传、普及营养知识。 相似文献
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艺术体操运动员体重控制方法研究 总被引：4，自引：0，他引：4
艺术体操运动的特点要求运动员体重轻、体形匀，因此体重控制是艺术体操运动员在训练过程中一个十分常见的问题。分析控制体重的实质，提出了艺术体操运动员体重控制的方法，并详细介绍了肉碱控制体重的生理机制及其在艺术体操运动员体重控制中的应用。 相似文献
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《European Journal of Sport Science》2013,13(2):191-199
Abstract The increased energy demand that occurs with incremental exercise intensity is met by increases in the oxidation of both endogenous fat and carbohydrate stores up to an intensity of ~70% V˙O2max in trained individuals. However, when exercise intensity increases beyond this workload, fat oxidation rates decline, both from a relative and absolute perspective. As endogenous glycogen use is accelerated, glycogen stores can become depleted, ultimately resulting in fatigue and the inability to maintain high intensity, submaximal exercise (>70% V˙O2max). Despite a considerable accumulation of knowledge that has been gained over the past half century, the precise mechanism(s) regulating muscle fuel selection and underpinning the aforementioned decline in fat oxidation remain largely unclear. A greater understanding would undoubtedly lead to novel strategies to increase fat utilization and, as such, improve exercise capacity. The present review primarily addresses one of the most prominent theories to explain the phenomenon of diminished fat oxidation during high intensity, submaximal exercise; a reduced availability of muscle free carnitine for mitochondrial fat translocation. This is discussed in the light of recent work in this area taking advantage of the discovery that muscle carnitine content can be increased in vivo in humans. Furthermore, the evidence supporting the recently proposed theory that reduced muscle co-enzyme A availability to several key enzymes in the fat oxidation pathway may also exert a degree of control over muscle fuel selection during exercise is also considered. Strong correlational evidence exists that muscle free carnitine availability is likely to be a key limiting factor to fat oxidation during high intensity, submaximal exercise. However, it is concluded that further intervention studies manipulating the muscle carnitine pool in humans are required to establish a direct causal role. In addition, it is concluded that while a depletion of muscle coenzyme A availability during exercise also offers a viable mechanism for impairing fat oxidation, at present, this remains speculative. 相似文献