补充肌酸的研究进展

研究认为，补充肌酸可增加肌肉重量，增强肌肉力量，缩短运动后肌肉恢复时间。研究表明，肌酸可能对高强度、短时间、间歇性运动有改善作用，对耐力性运动作用不明显。有人观察到补充肌酸可引起抽筋、脱水、腹泻、眩晕等副作用。目前可供使用的肌酸类型很多，应在医生的监督下合理选用。     

口服肌酸补充对人体运动的影响

最新研究表明，肌酸(Cr)补充能提高部分个体骨骼肌的磷酸肌酸(Cp)含量，从而提高一些项目的运动能力。现在职业运动员，优秀选手，业余运动员，及有发展前途的少年运动员均在服用肌酸。据估计，过去的一年肌酸的消耗量约为2.5×106kg。。这表明了人们对肌酸补充的极大期望。但过量服用，可能损害健康。尽管肌酸补充被认为是相对安全的，但它对健康的影响还没有科学的评价。1肌酸、肌酸代谢及肌酸补充的影响肌酸是一种非必需营养成分，肉类和鱼中含量丰富。体内主要在肝脏中合成，肌肉不能合成肌酸，靠肌膜上的Na 依赖载体从血液中摄取。在…     

肌酸补充与骨骼肌糖代谢

口服补充肌酸可使骨骼肌的肌酸摄取增强，但又受胰岛素水平、运动训练状况及肌纤雏型等多种因素的影响。肌酸补充后骨骼肌糖代谢能力增强，主要表现为血糖降低、骨骼肌糖原合成增强、骨骼肌葡萄糖转运蛋白4的表达上调，以及柠檬酸合酶活性升高。肌酸增强骨骼肌糖代谢的机制，可能与细胞体积增大而引发的细胞内信号转导改变有关。     

运动生物化学

根据肌酸的生物合成特点及其在能量代谢和疲劳中的作用,阐述了额外补充肌酸对运动效果的影响机理,并论述了大强度运动中补充肌酸的基本原理与方法。     

补充肌酸对大强度运动能力的影响

根据肌酸的生物合成特点及其在能量代谢和疲劳中的作用,阐述了额外补充肌酸对运动效果的影响机理,并论述了大强度运动中补充肌酸的基本原理与方法.     

补充肌酸对运动能力和健康的影响

骨骼肌能量代谢是运动生物化学的重要研究课题之一,磷酸肌酸(CP)属磷酸原供能系统,在短时间、以无氧代谢为主的运动中起主导作用。这就使人们对肌酸(Creatine)在骨骼肌能量代谢中的作用及其与运动能力的关系产生了极大兴趣。近年来,国内外许多学者对补充肌酸在提高运动能力作用方面的研究报道较多,因此,总结国内外对补充肌酸的研究成果,具有重要的参考意义。。     

补充糖和/或肌酸对赛后血清肌酸激酶活性的影响

8名男性足球运动员，按正交表L4(23)进行实验设计，进行关于糖、肌酸补充对足球运动员血清肌酸激酶活性影响的效果观察实验。A组仅补充空白饮料；B组每天补充20克肌酸；C组每天仅补充100克以低聚糖为主的饮料；D组同时补充肌酸和低聚糖饮料，补充方法同B、C组。连续补充5天。补充前后进行血清肌酸激酶浓度的测试。补充前测试时均喝空白饮料，补充后测试时补充相应饮料。测试前进行模拟现场比赛。模拟现场比赛分为两个半场，各45分钟，间隔15分钟。每个半场包15个3分钟的循环，测量每个半场后的血清肌酸激酶的浓度。结果表明：单独补充糖或肌酸，同时补充糖和肌酸均可使运动员赛后的即刻血清肌酸激酶活性显著下降，而且糖和肌酸同时补充效果好。提示同时补充糖、肌酸有利于足球运动员提高赛场竞技能力。     

补充肌酸对运动能力和健康的影响

就肌酸在能量代谢中的作用、补充肌酸对肌肉中肌酸含量的影响和对运动能力的影响等方面进行了文献综述与分析。     

2mM肌酸孵育对电刺激C2C12肌管细胞糖原合成通路的影响

目的:研究肌酸对骨骼肌糖原合成调节的影响及机制;方法:用培养的C2C12为细胞模型,用电刺激模拟神经冲动引起其收缩,测定肌酸孵育后电刺激下C2C12肌管细胞的糖原含量以及AMPKa1、HKⅡ及GS-Ⅰ等糖原合成通路中相关基因表达;结果:肌酸孵育能够有效促进电刺激下C2C12肌管糖原的合成,主要机制是糖原合成通路激活后,AMPKa1激活对糖原合成的正效应.但2mM肌酸孵育可能触发负反馈调节机制,抑制电刺激下C2C12肌管糖原合成相关酶基因的表达,维持细胞的内稳态;结论:细胞实验提示在体的肌酸补充能够促进骨骼肌糖原合成,增加肌糖原贮备,提高运动能力,为肌酸的合理补充提供参考依据.     

肌酸的补充与运动能力

本文从肌酸在能量代谢中的作用、补充肌酸对肌肉中肌酸含量的影响和对运动能力的影响等方面进行了文献综述与分析。     

肌酸的补充与运动能力(综述)

肌酸已成为最流行的能力增强剂。国外大量有关肌酸的文献认为,运动人体使用肌酸使运动后磷酸肌酸的再合成速度加快,力量和速度增强。肌酸使肌细胞通过水的摄取来促进蛋白合成率,从而改变体成分。肌酸同单糖一起使用可以刺激胰岛素的分泌,使肌肉摄取更多的肌酸。目前尚未见肌酸对肝、肾和血液系统功能的副作用和肌酸引起肌肉痉挛和损伤的研究报道。     

Building muscle: nutrition to maximize bulk and strength adaptations to resistance exercise training

Abstract

Several nutritional strategies can optimize muscle bulk and strength adaptations and enhance recovery from heavy training sessions. Adequate energy intake to meet the needs of training and carbohydrate intake sufficient to maintain glycogen stores (>7 g carbohydrate·kg^?1·day^?1 for women; >8 g carbohydrate·kg^?1·day^?1 for men) are important. Dietary protein intake for top sport athletes should include some foods with high biological value, with a maximum requirement of approximately 1.7 g·kg^?1·day^?1 being easily met with an energy sufficient diet. The early provision of carbohydrate (>1 g·kg^?1) and protein (>10 g) early after an exercise session will enhance protein balance and optimize glycogen repletion. Creatine monohydrate supplementation over several days increases body mass through water retention and can increase high-intensity repetitive ergometer performance. Creatine supplementation can enhance total body and lean fat free mass gains during resistance exercise training; however, strength gains do not appear to be enhanced versus an optimal nutritional strategy (immediate post-exercise protein and carbohydrate). Some studies have suggested that β-OH-methyl butyric acid (β-HMB) can enhance gains made through resistance exercise training; however, it has not been compared “head to head” with optimal nutritional practices. Overall, the most effective way to increase strength and bulk is to perform sport-specific resistance exercise training with the provision of adequate energy, carbohydrate, and protein. Creatine monohydrate and β-HMB supplementation may enhance the strength gains made through training by a small margin but the trade-off is likely to be greater bulk, which may be ergolytic for any athlete participating in a weight-supported activity.     

肌酸的补充与运动供能能力

本文综述了补充肌酸对运动中能量代谢的影响。肌酸作为1种能量补剂受到广泛关注。在参阅了大量文献后，笔者从肌酸对磷酸原供能系统、糖酵解供能系统和有氧氧化供能系统的影响，分析了肌酸对运动中能量代谢的影响。     

Dietary antioxidants and exercise

Muscular exercise promotes the production of radicals and other reactive oxygen species in the working muscle. Growing evidence indicates that reactive oxygen species are responsible for exercise-induced protein oxidation and contribute to muscle fatigue. To protect against exercise-induced oxidative injury, muscle cells contain complex endogenous cellular defence mechanisms (enzymatic and non-enzymatic antioxidants) to eliminate reactive oxygen species. Furthermore, exogenous dietary antioxidants interact with endogenous antioxidants to form a cooperative network of cellular antioxidants. Knowledge that exercise-induced oxidant formation can contribute to muscle fatigue has resulted in numerous investigations examining the effects of antioxidant supplementation on human exercise performance. To date, there is limited evidence that dietary supplementation with antioxidants will improve human performance. Furthermore, it is currently unclear whether regular vigorous exercise increases the need for dietary intake of antioxidants. Clearly, additional research that analyses the antioxidant requirements of individual athletes is needed.     

Dietary antioxidants and exercise

Muscular exercise promotes the production of radicals and other reactive oxygen species in the working muscle. Growing evidence indicates that reactive oxygen species are responsible for exercise-induced protein oxidation and contribute to muscle fatigue. To protect against exercise-induced oxidative injury, muscle cells contain complex endogenous cellular defence mechanisms (enzymatic and non-enzymatic antioxidants) to eliminate reactive oxygen species. Furthermore, exogenous dietary antioxidants interact with endogenous antioxidants to form a cooperative network of cellular antioxidants. Knowledge that exercise-induced oxidant formation can contribute to muscle fatigue has resulted in numerous investigations examining the effects of antioxidant supplementation on human exercise performance. To date, there is limited evidence that dietary supplementation with antioxidants will improve human performance. Furthermore, it is currently unclear whether regular vigorous exercise increases the need for dietary intake of antioxidants. Clearly, additional research that analyses the antioxidant requirements of individual athletes is needed.     

Nutritional needs of elite endurance athletes. Part II: Dietary protein and the potential role of caffeine and creatine

Abstract

Amino acids contribute between 2–8% of the energy needs during endurance exercise. Endurance exercise training leads to an adaptive reduction in the oxidation of amino acids at the same absolute exercise intensity, however, the capacity to oxidize amino acids goes up due to the increase in the total amount of the rate limiting enzyme, branched chain 2-oxo-acid dehydrogenase. There appears to be a modest increase (range?=?12–95%) in protein requirements only for very well trained athletes who are actively training. Although the majority of athletes will have ample dietary protein to meet any increased need, those on a hypoenergetic diet or during extreme periods of physical stress may need dietary manipulation to accommodate the need. Caffeine is a trimethylxanthine derivative that is common in many foods and beverages. The consumption of caffeine (3–7 mg/kg) prior to endurance exercise improves performance for habitual and non-habitual consumers. The ergogenic effect is likely due to a direct effect on muscle contractility and not via an enhancement of fatty acid oxidation. Creatine is important in intra-cellular energy shuttling and in cellular fluid regulation. Creatine monohydrate supplementation (20 g/d X 3–5 days) increases fat-free mass, improves muscle strength during repetitive high intensity contractions and increases fat-free mass accumulation and strength during a period of weight training. Given the increase in weight, there are likely neutral or even performance reducing effects in sports that are influenced by body mass (i.e., running, hill climbing cycling).     

补糖对不同时间运动后小鼠酮体代谢的影响

将昆明种4~6周龄雄性小白鼠随机分为补糖和补水对照组。每组均设安静组、定量运动组和力竭运动组。补糖采用浓度为5%葡萄糖与7%低聚糖的混合溶液。定量运动组做一次性静水负重游泳运动,持续时间为1h。力竭组与定量组运动形式相同,运动时间至力竭。分别测定血液、肝脏、骨骼肌和脑中的酮体(Ketone Body,KB),肝、骨骼肌糖原以及血糖、脑糖、血清游离脂肪酸(FFA)等指标。结果显示:与补糖组相比,1h游泳运动后补水组血清FFA有升高趋势,但无显著性差异,补水组小鼠血酮体浓度显著升高(P<0.05);力竭运动后补水组骨骼肌、肝脏中酮体含量显著高于补糖组(P<0.05)。提示:小鼠机体糖状况直接影响运动中的酮体代谢,运动性酮体代谢与体内糖储备以及脂肪分解状况有关。     

Beyond muscle: the effects of creatine supplementation on brain creatine,cognitive processing,and traumatic brain injury

Abstract

The ergogenic and therapeutic effects of increasing muscle creatine by supplementation are well-recognized. It appears that similar benefits to brain function and cognitive processing may also be achieved with creatine supplementation, however research in this area is more limited, and important knowledge gaps remain. The purpose of this review is to provide a comprehensive overview of the current state of knowledge about the influence of creatine supplementation on brain function in healthy individuals. It appears that brain creatine is responsive to supplementation, however higher, or more prolonged dosing strategies than those typically used to increase muscle creatine, may be required to elicit an increase in brain creatine. The optimal dosing strategy to induce this response, is currently unknown, and there is an urgent need for studies investigating this. When considering the influence of supplementation strategies on cognitive processes, it appears that creatine is most likely to exert an influence in situations whereby cognitive processes are stressed, e.g. during sleep deprivation, experimental hypoxia, or during the performance of more complex, and thus more cognitively demanding tasks. Evidence exists indicating that increased brain creatine may be effective at reducing the severity of, or enhancing recovery from mild traumatic brain injury, however, only limited data in humans are available to verify this hypothesis, thus representing an exciting area for further research.     

"复方抗氧化制剂"对大鼠运动能力和骨骼肌自由基代谢影响的研究

采用实验法,探讨“复方抗氧化制剂”及运动训练对大鼠骨骼肌自由基代谢、运动能力的影响。结果显示,训练组、补充组、补充训练组大鼠骨骼肌中SOD、CAT、GSH -PX活性都高于对照组,MDA含量都低于对照组,力竭游泳时间都明显延长。提示,“复方抗氧化制剂”能够并协同运动训练增强机体抗氧化能力,提高大鼠运动能力。