排序方式： 共有71条查询结果，搜索用时 15 毫秒
31.
Colleen George Michael T. Kopetzky Maysie J. Hughes James J. McGrath 《Research quarterly for exercise and sport》2013,84(1):25-30
Abstract Hearts from 126 male Sprague-Dawley rats (two age groups) were studied to determine effects of age, chronic hypoxia, and exercise on ventricular weight. Exercised rats had significantly heavier absolute total ventricular weights (right plus left) compared with chronically hypoxic or control rats. Whether expressed as absolute or percent total ventricular weight, chronically hypoxic rats had significantly larger right ventricles but significantly smaller left ventricles than exercised or control rats. Expressed as absolute weight, older rats (11 months) had significantly larger right or left ventricles than young rats (3 months). Expressed as percent total ventricular weight, young rats had left ventricles 4% smaller, but right ventricles 4% larger than older rats (p <.05). Type of work overload (volume or pressure) and functional location of workload (pulmonary or systemic) were suggested physiological mechanisms for stress- and age-related changes in myocardial mass. 相似文献
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采用文献资料法,对近年来骨骼肌肥大动物模型的研究现状进行了综述,同时对各种骨骼肌肥大动物模型分别从训练的相似性、运动负荷、肥大效果、运动维持方式以及训练时间安排等方面进行了分析和比较,总结出各模型的优点与不足.建议在骨骼肌肥大研究中,根据不同的研究需要和各类模型的特点,取长补短,进行模型复制. 相似文献
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目的:采用注射外源性IGF-I和一周跑台运动,观察对大鼠骨骼肌mTOR信号通路的影响,深入探讨IGF-I对运动骨骼肌适应性肥大的机理。方法:8周龄雄性SD大鼠在适应性训练后分为四组:安静组(S)、安静IGF-I组(SI)、运动组(E)、运动+IGF-I组(EI)。运动方式为跑台运动(20m/min,10%,60min/d),每天一次,共7天。外源性IGF-I为小腿后侧肌肉隆起处的皮下注射。用Western Blotting法检测腓肠肌MHC、PI3K、AKt、mTOR、p70S6K蛋白和Akt(Ser473)、mTOR(Ser2448)和p70S6K(Thr389)的磷酸化表达。结果:在一周后,外源性IGF-I显著促进骨骼肌MHC的表达,骨骼肌PI3K、Akt、mTOR蛋白和Akt(Ser473)、mTOR(Ser2448)和p70S6K(Thr389)的磷酸化表达显著增强。运动显著促进mTOR蛋白和Akt(Ser473)、mTOR(Ser2448)和p70S6K(Thr389)磷酸化的表达。对运动的反应,上述信号的磷酸化表达高于蛋白表达。结论:1)一周外源性IGF-I注射明显促进运动骨骼肌mTOR通路的活性;而1周跑台运动与IGF-I具有协同增强效应。2)在运动和注射外源性IGF-I的刺激下,mTOR通路各信号分子的磷酸化表达比蛋白表达更为敏感。建议今后对信号的研究以检测信号分子的磷酸化表达为主。 相似文献
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不同运动负荷对心脏超微结构与NO、NOS的影响 总被引：7，自引：3，他引：4
采用大鼠 8周递增负荷游泳训练模型 ,观察不同运动负荷方式对大鼠心脏超微结构的影响 ,以及血浆和心肌中舒血管因子一氧化氮NO、一氧化氮合酶NOS的变化 ,探讨不同运动负荷对大鼠的影响 ,并对其产生机制进行初步探讨。研究结果表明有氧训练能够使心肌的超微结构改善 ,提高心肌的cNOS活性、血浆NO水平 ,促进内皮组织舒张反应 ;大强度长时间的训练使心肌微细损伤出现 ,内皮组织损伤 ,但血浆NO水平变化不大。 相似文献
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摘要：目的：本研究旨在研究不同强度的急性运动对骨骼肌蛋白合成信号的影响,以期能深入阐明运动对骨骼肌蛋白合成代谢的调控机理。方法：8周龄SD雄鼠分别进行不同强度的跑台运动,于运动后即刻、6h 和12h 取材白腓肠肌。BCA法测肌肉蛋白浓度,Western Blot法测肌肉MHC和AR、mTOR、p70S6K、4EBP1、MEK、ERK和p90RSK的磷酸化。结果：①骨骼肌AR磷酸化在中强度运动后即刻、恢复期6h和12h分别增加13%、20%和14%,而在高强度运动后分别增加16%、57%和37%;②mTOR磷酸化在中强度和高强度运动后3个时间点均显著增加,分别增加19%、37%、4%和28%、53%、4%;p70S6K磷酸化分别增加28%、76%、18%和33%、96%、25%。4EBP1磷酸化分别增加18%、33%、7%和25%、44%、5%;③MEK磷酸化在在中强度和高强度运动后3个时间点均显著增加,分别增加74%、22%、3%和106%、51%、24%。ERK磷酸化分别增加39%、29%、11%和55%、32%、22%。p90RSK磷酸化分别增加22%、16%、4%和35%、20%、6%。结论：①骨骼肌AR活性、mTOR通路和MAPK通路的活性均存在运动强度依赖性,前两者均于运动后恢复期6h达到最高值,后者于运动后即刻达到最高值。②在运动后的恢复期中,AR活性在mTOR通路和MAPK通路大幅回落之后,仍保持较高的活性。 相似文献
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《European Journal of Sport Science》2013,13(3):295-303
Abstract Strength training and positive energy intake are the most important factors related to lean body mass (LBM) gain. Most studies investigating weight-gain interventions are based recreationally active subjects and less is known about optimal weight-gain protocols in elite athletes. The purpose of this study was to evaluate the effect of nutritional guidance in an 8- to 12-week weight-gain period in elite athletes. Thirty-nine elite athletes were randomised to either a ‘nutritional counseling group’ (NCG, n=21, 19.1±2.9 years, 70.9±8.9 kg) or ‘ad libitum group’ (ALG, n=18, 19.6±2.7 years, 75.0±5.9 kg). All athletes continued their sport-specific training which included an additional four strength-training sessions per week. NCG followed a meal plan providing a positive energy balance, while the ALG athletes had an ad libitum energy intake. Body weight (BW), body composition, one repetition maximum (1RM), 40 m sprint and counter movement jump (CMJ) were measured pre- and post-intervention. Energy intake was higher in the NCG than in the ALG (3585±601 vs. 2964±884 kcal) and consequently BW increased more in NCG than in ALG (3.9±0.6% vs. 1.5±0.4%). Fat mass (FM) increased more in NCG than in ALG (15±4 vs. 3±3%), but gain in LBM was not different between groups. All 1RM results improved in both groups (6–12%), whereas 40 m sprint and CMJ remained unchanged, except for a significant decrease in 40 m sprint for the athletes in NCG. Athletes with nutritional guidance increased BW more, however, excess energy intake in a weight-gain protocol should be considered carefully due to undesirable increases in body fat. 相似文献
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运动训练能促使骨骼肌在形态与结构上发生适应性的改变,如肌纤维类型转化、肌纤维选择性肥大等。钙调神经磷酸酶（CaN）是钙离子的下游因子,对细胞内因钙离子升高引起的心肌肥大起着重要作用。CaN的活性与肌纤维类型的表达和肌纤维选择性肥大有着非常紧密的联系。对CaN在运动过程中对心肌和骨骼肌的作用及调节进行综述。 相似文献
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Training frequency is considered an important variable in the hypertrophic response to regimented resistance exercise. The purpose of this paper was to conduct a systematic review and meta-analysis of experimental studies designed to investigate the effects of weekly training frequency on hypertrophic adaptations. Following a systematic search of PubMed/MEDLINE, Scoups, and SPORTDiscus databases, a total of 25 studies were deemed to meet inclusion criteria. Results showed no significant difference between higher and lower frequency on a volume-equated basis. Moreover, no significant differences were seen between frequencies of training across all categories when taking into account direct measures of growth, in those considered resistance-trained, and when segmenting into training for the upper body and lower body. Meta-regression analysis of non-volume-equated studies showed a significant effect favoring higher frequencies, although the overall difference in magnitude of effect between frequencies of 1 and 3+ days per week was modest. In conclusion, there is strong evidence that resistance training frequency does not significantly or meaningfully impact muscle hypertrophy when volume is equated. Thus, for a given training volume, individuals can choose a weekly frequency per muscle groups based on personal preference. 相似文献
40.
In this study of the relationship between hypertensive left ventricular hypertrophy (LVH) and neurohumor factors and ventricular
arrhythmias, 180 cases were divided at random into 3 groups: 60 cases with primary hypertension and LVH (PH+LVH); 60 cases
with simple hypertension (PH), and with other diseases and LVH(NPH+LVH). The results showed that 1. The excitability of the
sympathetic nerve was not elevated while the activity of the vagus nerve was not significantly decreased in the patients with
PH+LVH. The increased sympathetic nervous tension was correlated with the ventricular premature beat which was statistically
correlated with the myocardial ischemia. 2. The patients’ condition in group PH+LVH was not correlated with the levels of
aldosterone and insulin and was not even positively correlated with the levels of renin and angiotensin-II. 3. The patients
in group PH+LVH had high incidence of ventricular premature beat and myocardial ischemia. 4. The patients’ condition in group
NPH+LVH was not even positively correlated with the neurohumor factors but their heart failure was positively correlated,
with the levels of aldosterone, sympathetic nervous tension, myocardial ischemia and ventricular premature beat. 相似文献