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糖异生作用是指从乳酸、甘油、丙酮酸、生糖氨基酸等非糖物质生成葡萄糖或糖元。长期以来一直认为,在正常生理条件下肝脏是糖异生的主要器官,仅在饥饿和酸中毒时,肾脏也具备一些糖异生作用。骨骼肌被认为不具备糖异生作用的能力,因而,在大强度运动时糖酵解所产生的大量乳酸,必须首先进入血液循环运输到肝脏,再进行糖异生作用合成肝糖元或葡萄糖,骨骼肌从血液中吸收葡萄糖补充肌糖元,即Cori氏循环。 相似文献
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肌乳酸跨膜运输 总被引：1，自引：0，他引：1
孟思进 《武汉体育学院学报》2001,35(6):50-53
乳酸生成后的代谢去向主要是氧化清除.乳酸可以生成部位通过组织间隙和血液穿梭到邻近的高氧化能力部位.乳酸跨膜运输是在一元羧化乳酸运输蛋白(MCT)协助下沿浓度梯度和PH进行的.通过训练,骨胳肌和心肌细胞的MCT1含量会增加,结果摄取乳酸增加,乳酸生成后从骨胳肌外流增加.更重要的是,线粒体膜也含有MCT,这有助于乳酸在此进行氧化. 相似文献
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非乳酸代谢的定量分析包括能力和功率两方面,非乳酸能能力的大小与运动时骨胳肌内磷酸原浓度的变化有关,而非乳酸能功率大小与磷酸原裂解速率有关。Fox曾提出一种简单实用的最大非乳酸能能力(AL Cmax)测试法,但未受到重视,其可靠性也未曾证明过。此外,最大非乳酸能功率(AL Pmax)测试的可靠性同样也没验证过。本研究旨在提供这两种测试的可靠性情况。 相似文献
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骨髂肌,由被称为肌纤维的细肌胞构成的。过去认为肌纤维只有一种。可以把肌纤维做成薄的切片,用组织化学法染色以后,根据染色状态,始知可以划分为几个类型。大致分为Ⅰ型和Ⅱ型,Ⅱ型又可以细分成数型。可是这样划分的肌纤维型,如果染色方法不同,不一定和划分的类型一致。若是构成肌纤维的蛋白质,依分型有所不同,那么这种划分法是正确的。但是,因为构成同一肌纤维型的蛋白质不一定是均一的,所以说现在对肌纤维型的划分,还不能认为是准确的。另外,以生理功能为依据,划分肌纤维 相似文献
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张立 《武汉体育学院学报》1988,(1)
在科学选材中,肌纤维类型的测定已成为一个重要课题。采用肌电方法间接测定肌纤维类型,国内外学者做了大量工作。不同肌纤维类型代谢,收缩特征导致肌电参数各有差异。实验证明,快肌百分比较高的肌肉进行持续性收缩时积分肌电图(IEMG)增加,平均功率频率向低频转移。而慢肌百分比较高的肌肉积分肌电图振幅小于快肌振幅,功率谱变化小而稳定。机制主要是由于快肌运动单位较易疲劳,为维持力量输出,大量慢肌运动单位募集造成低频成分增加。此外快肌强大的收缩力量使肌内压增高,肌肉内供血不足和乳酸堆积是功率谱变化的另一个原因。这些机制已成为采用肌电方法测定肌纤维类型的主要依据。 相似文献
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肌酸及其复合制剂对小鼠运动能力的影响 总被引：1，自引：1，他引：0
本研究观察了口服肌酸及其复方制剂对小鼠运动能力影响,以及腓肠肌超微结构的变化。实验结果表明,服用肌酸及其复方制剂能显著提高小鼠运动能力,单纯服用肌酸不训练,运动能力变化P＞0．05,服用肌酸的同时给予适当的训练,运动能力变化P＜0.05;电镜观察小鼠腓肠肌中有较多的线粒体和糖原,肌纤维变粗。结果显示肌酸及其复合制剂能显著提高小鼠的运动能力,提高骨胳肌中能量物质储备。 相似文献
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纵观有关肌肉疲劳的文献,多数疲劳是由“外周性”因素引致的(神经肌肉接点的传递或肌纤维电化学活动),而不是“中枢性”因素(动机,中枢冲动缺陷)。肌纤维内部的代谢变化是导致疲劳的主要原因。ATP含量减少,乳酸和H~+浓度增高限制了肌肉力量。然而,由于病变或中毒而致使肌磷酸化酶缺乏的肌组织,尽管无法产生乳酸,但其疲劳的速度远快于正常肌组织。 相似文献
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对肌肉生物力学研究中有关问题的探讨 总被引：5，自引：0，他引：5
采用文献资料综述的研究方法，依据目前大量的肌肉生物力学研究成果，对研究内容、研究方法及体育运动中人体肌肉表现出的机能和生物力学特征等方面，进行较全面的探讨。内容主要涉及离体肌肉、在体肌肉、体育运动中下肢肌肉活动等，并提出有关问题进行讨论。 相似文献
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Martin D. Hoffman Natalie Badowski Joseph Chin Kristin J. Stuempfle Carol A. Parise 《Journal of sports sciences》2017,35(7):669-677
The primary study objective was to identify determinants of short-term recovery from a 161-km ultramarathon. Participants completed 400 m runs at maximum speed before the race and on days 3 and 5 post-race, provided a post-race blood sample for plasma creatine kinase (CK) concentration, and provided lower body muscle pain and soreness ratings (soreness, 10-point scale) and overall muscular fatigue scores (fatigue, 100-point scale) pre-race and for 7 days post-race. Among 72 race finishers, soreness and fatigue had statistically returned to pre-race levels by 5 days post-race; and 400 m times at days 3 and 5 remained 26% (P = 0.001) and 12% (P = 0.01) slower compared with pre-race, respectively. CK best modelled soreness, fatigue and per cent change in post-race 400 m time. Runners with the highest CKs had 1.5 points higher (P < 0.001) soreness and 11.2 points higher (P = 0.006) fatigue than runners with the lowest CKs. For the model of 400 m time, a significant interaction of time with CK (P < 0.001) indicates that higher CKs were linked with a slower rate of return to pre-race 400 m time. Since post-race CK was the main modifiable determinant of recovery following the ultramarathon, appropriate training appears to be the optimal approach to enhance ultramarathon recovery. 相似文献
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Julie A. Hides Tim Oostenbroek Melinda M. Franettovich Smith M. Dilani Mendis 《Journal of sports sciences》2016,34(24):2303-2311
ABSTRACTLow back pain (LBP) is a common problem in football (soccer) players. The effect of LBP on the trunk and hip muscles in this group is unknown. The relationship between LBP and trunk muscle size and function in football players across the preseason was examined. A secondary aim was to assess hip muscle strength. Twenty-five elite soccer players participated in the study, with assessments conducted on 23 players at both the start and end of the preseason. LBP was assessed with questionnaires and ultrasound imaging was used to assess size and function of trunk muscles at the start and end of preseason. Dynamometry was used to assess hip muscle strength at the start of the preseason. At the start of the preseason, 28% of players reported the presence of LBP and this was associated with reduced size of the multifidus, increased contraction of the transversus abdominis and multifidus muscles. LBP decreased across the preseason, and size of the multifidus muscle improved over the preseason. Ability to contract the abdominal and multifidus muscles did not alter across the preseason. Asymmetry in hip adductor and abductor muscle strength was found between players with and without LBP. Identifying modifiable factors in players with LBP may allow development of more targeted preseason rehabilitation programmes. 相似文献
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Luis Peñailillo Nicolás Guzmán José Cangas Alvaro Reyes Hermann Zbinden-Foncea 《European Journal of Sport Science》2017,17(2):179-187
The aim of this study was to examine the metabolic demand and extent of muscle damage of eccentric cycling targeting knee flexor (FLEX) and knee extensor (EXT) muscles. Methods: Eight sedentary men (23.3?±?0.7?y) underwent two eccentric cycling sessions (EXT and FLEX) of 30?min each, at 60% of the maximum power output. Oxygen consumption (VO2), heart rate (HR) and rated perceived exertion (RPE) were measured during cycling. Countermovement and squat jumps (CMJ and SJ), muscle flexibility, muscle soreness and pain pressure threshold (PPT) of knee extensor and flexor muscles were measured before, immediately after and 1–4 days after cycling. Results: FLEX showed greater VO2 (+23%), HR (+14%) and RPE (+18%) than EXT. CMJ and SJ performance decreased similarly after cycling. Muscle soreness increased more after EXT than FLEX and PPT decreased in knee extensor muscles after EXT and decreased in knee flexor muscles after FLEX. Greater loss of muscle flexibility in knee flexor muscles after FLEX was observed. Conclusion: Eccentric cycling of knee flexor muscles is metabolically more demanding than that of knee extensors, however muscle damage induced is similar. Knee flexors experienced greater loss of muscle flexibility possibly due to increased muscle stiffness following eccentric contractions. 相似文献
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运动性肌肉疲劳和细胞pH 总被引：2，自引：0，他引：2
卢昌亚 《山东体育学院学报》2001,17(3):26-27,30
新近有关运动疲劳时肌肉细胞和亚细胞机制的研究表明,细胞内pH下降是产生肌肉疲劳特征的重要因素.细胞内pH的下降能引起最大收缩力下降,收缩和舒张期延长,最大缩短速度下降以及最大收缩力和最大缩短速度同时下降所导致最大功率下降. 相似文献
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Linda Farrah Balog 《Research quarterly for exercise and sport》2013,84(2):119-125
Abstract This investigation examined the effects of physical exercise on muscle tension and subsequent muscle relaxation training. Twenty college students participated in the first phase of the study, which included a 10-minute EMG baseline, 30 minutes of pedalling on a bicycle ergometer, followed by EMG measurements on the frontalis muscle for up to 3 hours after the end of exercise. The same subjects from Phase I went on to Phase II, which included eight 32-minute EMG biofeedback training (BFT) sessions, utilizing the frontalis muscle. Ten subjects randomly assigned to the experimental group received BFT following an acute exercise bout, while the 10 subjects in the control group received no treatment. The greatest decrease in muscle tension in Phase I occurred 90 minutes after the end of the exercise. This finding was not significantly different from the baseline, indicating that there was no relaxation effect as a result of exercise. In Phase II, significant differences between pre and post-test measurements in both groups indicated that learning of relaxation did occur. However, no significant differences were found between the two groups, indicating that physical exercise did not enhance the learning of EMG BFT. 相似文献
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肌肉疲劳的细胞生物学机制及应对措施 总被引：8，自引：5，他引：3
对近年来有关肌细胞收缩及疲劳的细胞生物学机制研究成果进行了分析，探讨了相应的应对措施。指出肌细胞疲劳可能与肌细胞能量物质的耗竭、代谢产物的堆积、肌细胞损伤有关．并认为肌细胞的损伤是由于机械损伤、细胞内钙离子过载、线粒体钙超载、自由基脂质过氧化所致。建议从营养学的角度对运动员加强磷酸原、糖、碱性盐、抗氧化剂的补充，以防治肌细胞疲劳，提高运动成绩。 相似文献