Effects of stretch shortening cycle exercise fatigue on stress fracture injury risk during landing

The purpose of this study was to examine changes in landing performance during fatigue that could result in increased stress fracture injury risk. Five participants performed nonfatigued and fatigued drop landings (0.60 m), while ground reaction force (GRF), electromyographic (EMG) activity, and kinematics were recorded. Fatigue was defined as a 5-20% reduction in vertical jumping performance. Single-subject analyses revealed that all participants were affected (p < or = .05) by fatigue. Post hoc comparisons revealed a group effect (p < or = .05) for selected variables. Participants landed with (a) less joint flexion at contact and used a greater range of motion, (b) greater GRF peaks and loading rates, and (c) less EMG activity. These changes were consistent with greater risk of stress fracture.     

月经周期对女运动员耐力运动时物质代谢及激素变化的影响

综述了月经周期中雌、孕激素水平波动对耐力运动时物质代谢及相关激素的影响作用.前人的研究表明,中低强度运动时雌激素可增加脂类氧化,减少糖的利用,起着碳水化合物节省化效应.孕激素在雌激素作用的基础上提高脂类氧化,增加有氧运动能力.在雌、孕激素较高的黄体期进行有氧运动,机体氧化脂类能力高于卵泡期,利用碳水化合物能力低于卵泡期.月经周期对胰岛素、儿茶酚胺类激素、生长激素及糖皮质激素的基础值及运动诱导的反应值没有明显影响作用.因此,运动训练过程中应考虑月经周期时相对物质代谢的影响作用以期充分地发挥女性运动员的生理潜能.     

Effects of acute exercise on long-term memory

In this study, we tested the effect of acute exercise on long-term memory, specifically the timing of exercise relative to the memory challenge. We assessed memory via paragraph recall, in which participants listened to two paragraphs (exposure) and recounted them following a 35-min delay. Participants (n = 48) were randomly assigned to one of three groups: exercise prior to exposure, exercise after exposure, or no-exercise. Exercise consisted of 30 min on a cycle ergometer including 20 min at moderate intensity. Only the exercise prior group recalled significantly more than the control group (p < .05). Differences among the exercise groups failed to reach significance (p = .09). Results indicated that acute exercise positively influenced recall and that exercise timing relative to memory task may have an impact on this effect.     

Effects of exercise on bone mineral content in postmenopausal women

The purpose of this study was to test the effects of a 10-month exercise program on bone mineral content (BMC) and bone mineral content/bone width (BMC/BW) of postmenopausal women. Thirty-one women (ages 57-83) completed either a general aerobics exercise program (n = 10), a general aerobics plus upper body weight training exercise program (n = 10), or served as nonexercising control subjects (n = 11). Average compliance rates for the exercise subjects ranged from 72 to 80%. All subjects were pre- and posttested for BMC and BMC/BW in the radius of the nondominant forearm. ANOVA results indicated that there were significant differences between the exercise and control subjects in the amount of change in BMC and in BMC/BW (p less than .05) during the course of the study. The exercise subjects experienced mean increases of 1.38% and 1.33% in BMC and BMC/BW, respectively, whereas the control group had decreases of 2.50% and 2.58%. No significant differences were found for subjects in the two types of exercise programs, suggesting that the effects of exercise relative to maintenance of bone density may be general as well as localized.     

白藜芦醇对大强度耐力训练大鼠部分生化指标的影响

通过给大强度耐力大鼠服用白藜芦醇,测试有关生化指标,研究白藜芦醇对大鼠运动能力影响的可能机制,为白藜芦醇在运动医学领域应用和运动保健饮料、食品的开发提供参考。以雄性SD大鼠为研究对象,递增强度跑台训练,建立大强度耐力运动模型,测定血清中ALT、AST、CK、LDH、ALP、TP、ALB、BU及Hb、肝糖原、肌糖原等反映机体机能、蛋白质代谢的指标。结果显示,服用白藜芦醇的运动组与单纯运动组相比,运动后大鼠体内Hb、肝糖原、肌糖原等指标均明显升高;白藜芦醇可明显减轻大强度运动对大鼠肝脏和心肌等组织细胞的损伤,运动＋白藜芦醇组大鼠血清ALT、AST、LDH、CK、ALP活性显著低于运动组;服用白藜芦醇后的大鼠运动后血清BU含量显著低于相应的对照组,而TP、ALB含量则明显升高。本实验提示,大鼠服用白藜芦醇有利于能源物质的积累与储存,维持细胞的正常结构与功能,减少蛋白质的消耗和利用,可显著提高大鼠运动至力竭的时间,延缓运动性疲劳的发生。     

长期运动训练对外周血淋巴细胞DNA损伤和凋亡的影响及机制研究

训练组(男子足球运动员,n=16)和对照组(男子大学生,n=16)在功率自行车上完成一次递增负荷力竭运动。运动前、运动后以及运动后24 h采集静脉血,测定外周血淋巴细胞计数、淋巴细胞凋亡率、羟自由基、8-羟基脱氧鸟嘌呤(8-OHdG)和8-氧鸟嘌呤DNA糖基化酶(OGG1)。结果发现,运动后即刻,训练组和对照组外周血淋巴细胞计数(P<0.01;P<0.05)、淋巴细胞凋亡率(P<0.05;P<0.01)、羟自由基(P<0.01;P<0.01)、8-OHdG(P<0.01;P<0.01)和OGG1(P<0.01;P<0.01)均高于运动前水平,而训练组OGG1升高幅度高于对照组(P<0.01),其他各指标升高幅度则均明显低于对照组(均为P<0.01)。运动后24h,对照组外周血淋巴细胞计数低于运动前(P<0.01),淋巴细胞凋亡率高于运动前(P<0.01),而训练组则恢复至运动前;两组8-OHdG(P<0.05;P<0.01)均高于运动前,但升高幅度明显低于对照组(P<0.01);OGG1在对照组恢复至运动前,而训练组仍高于运动前水平(P<0.05)。因此,长期运动训练通过降低氧化应激水平、提高DNA修复能力、减轻DNA氧化损伤,抑制运动性淋巴细胞凋亡。     

运动性骨骼肌损伤机制的研究进展

从损伤机制和检测指标两个方面对运动性骨骼肌损伤的研究进展进行综述,结果表明:运动性骨骼肌损伤主要原因为机械外力导致骨骼肌的肌膜完整性、流动性和通透性受损,进而导致骨骼肌细胞内钙离子超载,细胞膜的脂质过氧化,一些蛋白如Caveolin-3、Calpains和Ubiquitin的表达改变可能参与了细胞内的钙超载调控,机械性外力作用和代谢性刺激综合作用可以诱发、加重骨骼肌微结构的损伤.     

膳食脂肪对运动能力的影响及运动时脂代谢的调节

就膳食脂肪对运动能力的影响以及脂肪代谢的调节作一综述。运动强度、时间不同，脂肪供能所占的比例不同，脂肪供能对运动成绩的影响也有所差异。运动时脂代谢的调节受多种因素的影响，激素敏感性甘油三酯脂肪酶(HSL)是酶解速度的主要控制因素。     

我省参加“十一运”优秀女子举重运动员的月经周期情况调查分析

目的：旨在探讨女子举重运动员初潮年龄、月经失调情况等特点,为科学训练提供理论依据。对象与方法：采用问卷调查法对山东省参加第十一届全运会的优秀女子举重运动员的月经周期情况进行调查。结果：运动员初潮年龄在正常范围内;运动员月经失调发病率较高。结论：举重运动训练对月经周期有一定影响,运动训练要根据月经周期安排。     

不同负荷运动对大鼠肾组织ICAM - 1和P - Selectin 表达的影响

目的:通过游泳方法建立大鼠运动模型,观察了不同运动负荷状态下大鼠肾脏的组织病理变化和相关黏附分子的表达。结果显示:对照组肾小管形态结构正常,间质无充血、水肿。一般运动负荷组肾小管排列略微紊乱,肾小管有轻度变性,肾小球轻度肿大。运动超负荷组肾小管排列稀疏、紊乱,肾小管扩张,肾小管、肾小球严重变性。正常情况下,ICAM-1在肾脏组织中表达极少,而在超负荷运动组大鼠的肾小球内皮细胞、肾小管上皮细胞可见到ICAM-1的大量表达,统计学结果也显示运动超负荷组ICAM-1较对照组显著增加;对照组中可见P-选择素表达于肾脏小血管内皮细胞,肾小球内皮细胞和肾小管上皮细胞未见P-选择素的表达,一般运动负荷组可见P-选择素表达于肾小管上皮细胞,其表达与对照组无显著性差异。运动超负荷组肾小管上皮细胞大量表达P-选择素,满布整个视野,染色很深,且比对照组显著增加。提示ICAM-1、P-选择素指标可以作为过度训练的诊断指标。     

谷氨酰胺对运动性免疫抑制的作用

长时间运动应激能引起血浆谷氨酰胺的浓度下降并发生短暂免疫抑制,从而增加运动员上呼吸道感染的发病率和胃肠疾病的发生率.运动员补充谷氨酰胺后,疾病的发生率有所下降,这与谷氨酰胺在免疫系统中的作用密切相关.对运动性免疫抑制的发生和耐力运动后疾病的发生情况作一综述,并探讨了补充谷氨酰胺的作用及作用的机制.     

中等强度运动对去卵巢大鼠子宫刺激、骨骼肌MDA含量及SOD、GSH-PX活性的影响

目的:探讨中等强度运动对去卵巢子宫刺激、骨骼肌MDA含量及SOD、GSH-PX活性的影响。方法:将48只3月龄雌性大鼠按体重随机分成假手术组(Sham组)、造模组(Model组)、己烯雌酚组(DES组)、运动组(EX组),每组12只,假手术组仅切除卵巢附近一团脂肪,其余各组均切除双侧卵巢。术后按不同要求灌胃给药和运动,12周后称重后处死大鼠。分离子宫,测量子宫湿重及子宫内膜厚度。取各组大鼠股四头肌制备成10%的组织匀浆行MDA、SOD、GSH-PX检测,统计分析各组数据。结果:与DES组比较,其它各组体重显著降低(P<0.05或P<0.01);与DES组比较,其它各组子宫内膜厚度极显著降低(P<0.01);与Model组比较,DES组和EX组MDA均显著升高(P<0.05),SOD、GSH-PX均显著下降(P<0.05或P<0.01)。结论:中等强度的运动能维持去卵巢大鼠体重;对子宫刺激作用较雌激素低;能显著降低去卵巢大鼠骨骼肌MDA含量,增强SOD、GSH-PX活性,减少自由基的堆积,提高机体抗氧化能力,改善骨骼肌性能,延缓骨骼肌衰老。较雌激素药物干预更安全,优势明显,可作为临床选择。     

运动与儿童少年骨密度的改变

运动负荷是骨生长、发育和成熟的重要影响因素。采用文献资料法，论述了适量运动可增加儿童少年的骨密度，而运动缺乏与运动过度会对其骨密度产生负面影响，并就其影响机制、研究中存在的问题及其研究发展方向进行探讨。     

Effects of dynamic upper-body exercise on lower-limb isometric endurance

Following preliminary indications that in some individuals arm exercise enhanced rather than reduced simultaneous leg endurance, ten young men and women performed three forms of intermittent work to volitional exhaustion, under duty cycles of 45 s work, 15 s rest. The protocols were as follows: (A) knee extensions at 30% maximum voluntary contraction (MVC); (B) 30% MVC knee extensions combined with arm cranking at 130% of their own lactate threshold; (C) combined 30% MVC knee extensions and arm cranking at 20% of their own lactate threshold. Heart rate, oxygen uptake (VO(2)), and blood lactate concentration were among the variables recorded throughout. All physiological indicators of demand were substantially higher in protocol B than in protocols A or C [heart rate: (A) 154 beats . min(-1), (B) 171 beats . min(-1), (C) 150 beats . min(-1); VO(2): (A) 11.9 ml . kg(-1) . min(-1), (B) 21.7 ml . kg(-1) . min(-1), (C) 14.2 ml . kg(-1) . min(-1); blood lactate concentration: (A) 3.3 mmol . l(-1), (B) 5.1 mmol . l(-1), (C) 2.8 mmol . l(-1)], yet there were no significant differences (P > 0.05) in the endurance times between the three conditions [(A) 11.43 min, (B) 11.1 min, (C) 10.57 min] and seven participants endured longest in protocol B. Results from protocol (C) cast doubt on explanations in terms of psychological distraction. We suggest that lactic acid produced by the arms is shuttled to the legs and acts there either as a supplementary fuel source or as an antagonist to the depressing effects of increased potassium concentration.     

运动对24小时动态血压的影响

采用文献资料法综述近年来国内外有关运动对24小时动态血压的影响的研究表明,一次性运动后会导致血压在一定时间下降(可持续22小时),有时甚至低于对照水平(运动后低血压),长期进行中等强度的有氧运动对血压正常者或高血压患者24小时的动态血压具有较好的降压效果。遗传、神经体液因素的改变、血管结构及血管反应性的改变、体重降低以及胰岛素抵抗的降低等都可部分解释运动的降压作用。     

等动训练对促进膝关节病患者肌力恢复的研究

运用Ｃｙｂｅｘ－６０００型等动测力系统对３０名膝ＯＡ患者进行膝并节肉屈伸的等动练习,结果表明,经过３－４周的练习治疗后,膝关节屈伸肌群的最大肌力矩,平均输出功率,爆发力及所做的总功都有所增加,步行,上楼,从椅上站起等日常动作显著改善,膝关节疼痛缓解。等动训练有助于促进膝关节病者肌内的恢复。     

运动对细胞凋亡的影响(综述)

细胞凋亡(apoptosis)是一种由基因控制的细胞自主性死亡过程，其性质为生理性细胞死亡。细胞凋亡的研究已成为生物医学领域中最热门的课题之一。然而在运动医学中的研究尚不多见，为此就运动对细胞凋亡影响的一些新的研究进展进行了综述。