5000米跑耐力训练对新兵有氧耐力及左心室结构和功能的影响

目的:严格控制实验条件,观察18周5000米长跑耐力训练效果,为基因多态与训练效果的关联性分析提供基础数据。方法:102名中国汉族士兵每周训练3次,采用前10周95%VTHR(通气无氧阈时的心率)±3和后8周105%VTHR±3来控制跑速。用体成分测定仪测定18周训练前后受试者的体成分,通过递增负荷跑台运动,分别于训练前后测定VO2max(最大摄氧量)、VT(通气无氧阈)、RE(跑节省化)实验中相关有氧耐力指标,通过定量负荷蹬车运动测定训练前后左心室结构与功能相关指标。结果:18周训练后受试者VO2max较训练前平均增加了1·56%(P<0·01),VT时摄氧量提高了2·59%(P<0·05),RE时的摄氧量较训练前下降7·60%~9·43%(P<0·01);训练后左心室每搏量增加、心输出量节省化和左室重量增加。结论:5000跑耐力训练可明显提高受试者有氧耐力水平,递增负荷下左心室结构与功能呈现良好的顺应性变化。     

不同训练方法对士兵耐力素质训练的影响

目的 探求一种适合常规部队、能快速有效提高士兵有氧耐力素质、并可降低军事训练伤发生率的训练方法.方法 随机抽取某步兵团248名无军事训练史的汉族男性新兵,均分为实验组和对照组,每组124名.实验组采用以"循环训练法"为理念设计的强化耐力训练方法;对照组采用部队常用耐力训练方法,即以5000m跑为主的训练方法(每周5000m×3次,每日不超过1次).两组总共进行8周的耐力素质训练.训练开始前和训练8周后分别测试士兵的安静脉搏、肺活量、VO2max和5000m成绩等耐力素质指标,并于训练8周后对士兵进行体检,统计有小腿肿胀和按压痛、膝关节肿痛、下腰痛等军事训练伤症状的人数,计算军事训练伤发生率.结果 实验组训练后安静脉搏降低了8.0%,肺活量、VO2max、5000m成绩则分别提高了8.1%、20.0%、14.7%,与训练前及对照组比较差异均有统计学意义(P<0.01或P<0.05).实验组训练伤发生率(3.3%)显著低于对照组(8.1%,P<0.05).结论 以"循环训练法"为理念设计的强化耐力训练方法可有效提高部队士兵耐力素质并减少军事训练伤的发生.     

耐力速度复合训练对新兵膝屈伸肌功能影响的等速测试研究

为探讨耐力速度复合训练对新兵膝屈伸肌功能的影响，对20名新兵进行为期4周的耐力速度复合训练，训练前后采用Cybex-6000型等速运动测试仪对新兵的膝屈伸肌肌力、肌爆发力及肌耐力进行等速测试并加以比较。结果发现，新兵训练后左膝屈肌的PT、TAE和ER值在快速测试中有明显的提高（P＜0．05）；左膝伸肌的PT和ER值在快速测试中有明显的提高（P＜0．05）；右膝屈伸肌除屈肌的PT、TAE值在快速测试中有明显的提高外余检测指标无改变。提示为期4周的耐力速度复合训练可使部分膝屈伸肌产生适应，但不能达到全面发展新兵膝屈伸肌肌力、肌爆发力和肌耐力的目的。     

耐力训练与补充不同剂量L-Arg对大鼠股外肌NOS基因表达的影响

目的:本研究旨在探讨耐力训练和补充不同剂量外源性L-Arg对耐力训练后和力竭运动恢复期大鼠股外肌NOS基因表达的影响.方法:采用定量反转录聚合酶链式反应(QRT-PCR)检测股外肌NOS三种亚型(eNOS、nNOS、iNOS)的基因表达.结果:耐力训练显著上调eNOS、nNOS表达(P< 0.01),有上调iNOS表达的趋势;补充小剂量L-Arg可下调nNOS的表达(P < 0.05),有上调iNOS表达的趋势;补充大剂量上调nNOS表达(P < 0.05),有下调iNOS表达的趋势.结论:耐力训练上调eNOS、nNOS、iNOS的表达;补充外源性L-Arg对nNOS、iNOS基因表达的影响可能存在一定的剂效关系.     

反复体位改变训练对人体立位耐力的影响

目的验证反复体位改变训练提高人体立位耐力的有效性 ,并探讨其机理。方法 6名被试者经受了为期 1 1d共 9次的反复体位改变训练。在训练前和训练后利用头高位倾斜检查立位耐力。结果训练后 ,被试者在立位耐力检查中的反应得到改善 ,表现为与训练前相比立位中不良症状明显减轻 (症状得分 4.5 0± 1 .0 5vs .2 .83± 1 .60 ,P <0 .0 5 ) ,心率的增量明显降低 [( 2 9.3± 4.3)bpmvs .( 1 3.5± 7.5 )bpm ,P <0 .0 1 ],平均动脉压的增量明显增加 [( 4 .8± 4.4)mmHgvs.( 9.0± 3.0 )mmHg ,P <0 .0 5 ],心血管反应指数明显减小 ( 34.42± 5 .0 0vs.2 2 .33± 8.2 7,P <0 .0 1 )。结论反复体位改变训练可提高人体立位耐力。该训练有望在飞行员 ,特别是航天员训练中得到应用     

长期耐力训练对武警战士运动和静息状态血压的影响

 目的本研究结合武警部队战士训练大纲和训练实际,研究耐力性训练对武警战士血压的影响,为科学训练与监控提供基础资料.方法采用持续跑、间歇跑进行为期12周的耐力训练,测量训练前后运动和静息状态血压的变化.结果武警战士经过阶段性耐力训练后,静息状态下,SBP从(115.15±9.26)mmHg降为(110.82±8.84)mmHg,平均下降了4.33mmHg(P＜0.01);DBP下降了1.6 mmHg(P＞0.05).一次性耐力运动负荷的测试结果表明,实验后运动即刻SBP、DBP和实验前相比分别下降了4.44mmHg和2.18 mmHg(均为P＞0.05).恢复期5 min的比较结果为:SBP分别为(128.18±8.91)mmHg和(122.56±5.07)mmHg(P＜0.05);DBP分别为(72.18±5.41)mmHg和(71.43±4.81)mmHg(P＞0.05).结论长期耐力训练对武警战士运动和静息状态血压产生有利的影响.     

不同强度不同时间耐力训练对于大鼠心肌细胞自噬发生程度的影响

目的:探讨不同强度不同时间耐力训练对大鼠心肌细胞自噬程度的影响,为运动强度和时间对心肌细胞自噬发生机制的探讨提供依据。方法:选用48只健康成年雄性SD大鼠,随机分为安静对照组、中等强度训练组和大强度训练组,每组16只。分别以15.2 m/min速度5°坡度和28 m/min速度10°坡度进行跑台训练,每周训练5天,每次训练1小时。于第8周和16周分别取各组大鼠8只进行体重称量、超声心动图检测,计算心脏重量指数(HWI);取左心室壁用于HE染色,观察心肌组织形态;制备超薄切片进行透射电镜观察,检测自噬发生程度。结果:运动训练16周后,大强度组HWI显著低于同期对照组及同组训练8周后(P<0.05)。超声心动图显示,训练8周后,中等强度组EF值显著高于同期对照组(P<0.05);训练16周后,中等强度组LVPWD、LVPWS、EF均显著高于同组训练8周后,大强度组EF值显著低于同期对照组(P<0.05)。HE染色结果显示,大强度组心肌细胞损伤严重。透射电镜检测显示,长时间大强度耐力训练使自噬小体增多,自噬程度增加。结论:耐力训练可引起心肌组织细胞良好的适应性重塑,但大强度长时间耐力训练会导致心肌纤维形态异常,线粒体损伤聚变,自噬体增多等病理现象,构成心肌损伤的结构基础。     

有氧耐力训练对增龄大鼠骨骼肌线粒体生物合成的影响

目的:观察增龄大鼠骨骼肌线粒体生物合成的变化特点,探讨有氧耐力训练诱导增龄大鼠骨骼肌线粒体生物合成的分子机理。方法:中等强度跑台运动(64%VO2max,5°,15m/min,45min,每周5天)施加于2、12和17月龄雄性大鼠共12周,对照组正常饲养。12周后取大鼠比目鱼肌和股外侧深层肌进行分子生物学指标检测。结果:(1)增龄过程中,PGC-1α和NRF-1 mRNA表达、mtTFA蛋白表达随增龄显著增加,而mtTFA和COXIV mRNA表达、PGC-1α和COXIV蛋白表达随增龄无显著变化。(2)耐力训练后,5MT组PGC-1α mRNA和蛋白表达、15MT组PGC-1α mRNA表达显著高于各自对照组,5MT和15MT组NRF-1 mRNA表达分别显著高于各自对照组,20MT组PGC-1α mRNA和蛋白表达、NRF-1 mRNA表达相对于20MC组无显著变化,各月龄训练组mtTFA mRNA表达、COXIV mRNA和蛋白表达均显著高于各自对照组。结论:(1)增龄过程中PGC-1α、NRF-1、mtTFA和COXIV mRNA和蛋白水平的变化呈现非同步趋势,提示增龄过程中线粒体生物合成受复杂的多条途径调控;(2)耐力训练能够诱导PGC-1α、NRF-1、mtTFA和COXIV表达显著增加,促进骨骼肌线粒体生物合成;(3)耐力训练诱导骨骼肌线粒体生物合成的适应性积累效应随着大鼠年龄递增逐渐递减。     

穴位离子导入对耐力训练大鼠心肌蛋白激酶C表达的影响

目的 :探讨穴位离子导入对耐力训练大鼠心肌蛋白激酶C(PKC)蛋白及mRNA水平表达的影响。方法 :通过免疫组化、RT -PCR方法观察离子导入对PKC蛋白及其mRNA表达的影响。结果 :PKC在正常对照组中主要存在于胞浆内 ,大强度跑台训练后在细胞膜上和细胞核内可见 ,经口服中药和穴位离子导入干预后 ,心肌PKC阳性表达面积明显增加 ,两者合用能进一步促进PKC的表达。各实验组PKCmRNA表达均明显高于安静对照组 ,尤以离子导入和口服中药联合应用效果更加明显。结论 :穴位离子导入可激活PKC ,使其发生转位 ,促进其蛋白、mRNA表达 ,且口服中药与穴位离子导入之间具有协同作用 ,说明激活PKC途径可能是离子导入保护心脏 ,预防疲劳的重要机制之一。     

耐力训练对大鼠骨骼肌超微结构及IGF-1表达影响的研究

目的探讨大鼠骨骼肌对中等负荷耐力训练的适应性变化。方法40只雄性Wiser大鼠进行上坡跑中等负荷运动，观察不同训练阶段大鼠比目鱼肌的超微结构和IGF-1表达的变化。结果组织病理学观察示大鼠比目鱼肌发生了运动性肌肉损伤，且在第3周时损伤最重，出现骨骼肌结构相对“薄弱期”。同时，肌组织中IGF-1水平明显升高。肌组织在损伤后即开始自行修复，运动4周后，Z线异常率和IGF-1水平逐渐降低，病理改变逐渐减轻。结论肌肉损伤有一个逐渐加重后经修复逐渐减轻的过程，说明在损伤积累的同时，肌肉表现出良好的适应能力。     

Effects of submaximal and supramaximal interval training on determinants of endurance performance in endurance athletes

We compared the effects of submaximal and supramaximal cycling interval training on determinants of exercise performance in moderately endurance‐trained men. Maximal oxygen consumption (VO_2max), peak power output (P_peak), and peak and mean anaerobic power were measured before and after 6 weeks (3 sessions/week) of submaximal (85% maximal aerobic power [MP], HIIT₈₅, n = 8) or supramaximal (115% MP, HIIT₁₁₅, n = 9) interval training to exhaustion in moderately endurance‐trained men. High‐intensity training volume was 47% lower in HIIT₁₁₅ vs HIIT₈₅ (304 ± 77 vs 571 ± 200 min; P < 0.01). Exercise training was generally associated with increased VO_2max (HIIT₈₅: +3.3 ± 3.1 mL/kg/min; HIIT₁₁₅: +3.3 ± 3.6 ml/kg/min; Time effect P = 0.002; Group effect: P = 0.95), P_peak (HIIT₈₅: +18 ± 9 W; HIIT₁₁₅: +16 ± 27 W; Time effect P = 0.045; Group effect: P = 0.49), and mean anaerobic power (HIIT₈₅: +0.42 ± 0.69 W/kg; HIIT₁₁₅: +0.55 ± 0.65 W/kg; Time effect P = 0.01; Group effect: P = 0.18). Six weeks of submaximal and supramaximal interval training performed to exhaustion seems to equally improve VO_2max and anaerobic power in endurance‐trained men, despite half the accumulated time spent at the target intensity.     

No effect of dietary nitrate supplementation on endurance training in hypoxia

We investigated whether dietary nitrate (NO₃^?) supplementation enhances the effect of training in hypoxia on endurance performance at sea level. Twenty‐two healthy male volunteers performed high‐intensity endurance training on a cycle ergometer (6 weeks, 5×30 min/week at 4–6 mmol/L blood lactate) in normobaric hypoxia (12.5% FiO₂), while ingesting either beetroot juice [0.07 mmol NO₃^?/kg body weight (bw)/day; BR, n = 11] or a control drink (CON, n = 11). During the pretest and the posttest, the subjects performed a 30‐min simulated time trial (TT) and an incremental VO_2max test. Furthermore, a biopsy was taken from m. vastus lateralis before and after the TT. Power output during the training sessions in both groups increased by ～6% from week 1 to week 6 (P < 0.05). Compared with the pretest, VO_2max in the posttest was increased (P < 0.05) in CON (5%) and BR (9%). Power output corresponding with the 4 mmol/L blood lactate threshold, as well as mean power output during TT increased by ～16% in both groups (P < 0.05). Muscle phospho‐AMP‐activated protein kinase, hypoxia inducible factor‐1α mRNA content, and glycogen breakdown during the TT were similar between the groups in both the pretest and the posttest. In conclusion, low‐dose dietary NO₃^? supplementation does not enhance the effects of intermittent hypoxic training on endurance exercise performance at sea level.     

Heart rate variability in prediction of individual adaptation to endurance training in recreational endurance runners

The aim of this study was to investigate whether nocturnal heart rate variability (HRV) can be used to predict changes in endurance performance during 28 weeks of endurance training. The training was divided into 14 weeks of basic training (BTP) and 14 weeks of intensive training periods (ITP). Endurance performance characteristics, nocturnal HRV, and serum hormone concentrations were measured before and after both training periods in 28 recreational endurance runners. During the study peak treadmill running speed (V_peak) improved by 7.5±4.5%. No changes were observed in HRV indices after BTP, but after ITP, these indices increased significantly (HFP: 1.9%, P=0.026; TP: 1.7%, P=0.007). Significant correlations were observed between the change of V_peak and HRV indices (TP: r=0.75, P<0.001; HFP: r=0.71, P<0.001; LFP: r=0.69, P=0.01) at baseline during ITP. In order to lead to significant changes in HRV among recreational endurance runners, it seems that moderate‐ and high‐intensity training are needed. This study showed that recreational endurance runners with a high HRV at baseline improved their endurance running performance after ITP more than runners with low baseline HRV.     

Effects of resistance training on endurance capacity and muscle fiber composition in young top-level cyclists

Equivocal findings exist on the effect of concurrent strength (S) and endurance (E) training on endurance performance and muscle morphology. Further, the influence of concurrent SE training on muscle fiber-type composition, vascularization and endurance capacity remains unknown in top-level endurance athletes. The present study examined the effect of 16 weeks of concurrent SE training on maximal muscle strength (MVC), contractile rate of force development (RFD), muscle fiber morphology and composition, capillarization, aerobic power (VO2max), cycling economy (CE) and long/short-term endurance capacity in young elite competitive cyclists (n=14). MVC and RFD increased 12-20% with SE (P<0.01) but not E. VO2max remained unchanged. CE improved in E to reach values seen in SE. Short-term (5-min) endurance performance increased (3-4%) after SE and E (P<0.05), whereas 45-min endurance capacity increased (8%) with SE only (P<0.05). Type IIA fiber proportions increased and type IIX proportions decreased after SE training (P<0.05) with no change in E. Muscle fiber area and capillarization remained unchanged. In conclusion, concurrent strength/endurance training in young elite competitive cyclists led to an improved 45-min time-trial endurance capacity that was accompanied by an increased proportion of type IIA muscle fibers and gains in MVC and RFD, while capillarization remained unaffected.     

Effects of strength and endurance training on antioxidant enzyme gene expression and activity in middle-aged men

This study was aimed at investigating the effects of a 21-week period of progressive strength or endurance training on peripheral blood mononuclear cells (PBMC) antioxidant enzyme gene expression and activity in healthy middle-aged untrained men. Strength ( n =11) and endurance ( n =12) training were performed twice a week, including resistance exercises to activate all the main muscle groups or cycle-ergometer pedaling, respectively. mRNA levels of catalase, glutathione peroxidase (GPx), mitochondrial superoxide dismutase (MnSOD) and cytosolic superoxide dismutase (CuZnSOD) were increased after 21 weeks of strength training, while endurance training induced significant changes only in MnSOD and GPx mRNA levels. CuZnSOD protein content was significantly increased only in strength-trained subjects. The program of strength or endurance exercise training had no significant effects on the activity of any of the antioxidant enzymes. In conclusion, in a middle-aged population, 21 weeks of strength or endurance training was a sufficient stimulus to up-regulate mRNA levels of PBMC antioxidant enzymes, the strength training being a more optimal stimulus. However, the discrepancies between enzyme protein and mRNA levels suggest that the present systematic strength or endurance training period had no beneficial effects on enzymatic antioxidant defense mechanisms in previously untrained middle-aged men.     

Amateur endurance cycling practice and adult’s physical and psychosocial health: a cross-sectional study of the influence of training volume

ABSTRACT

This study aimed to analyse the association between amateur cycling training volume and physical and psychosocial health. A cross-sectional study was developed, via self-reported survey, among 1669 cyclists and 1039 controls, where analysis of variance and hierarchical multiple linear regression test were developed. Independent of gender, high volumes of amateur endurance cycling practice benefited cyclists’ body mass index and male cyclists’ physical conditioning, while psychosocial health did not differ among the training volume groups. Hierarchical multiple linear regression analysis highlighted the contribution of training volume to lower cyclists’ body mass index and better male cyclists’ physical conditioning. All cyclist groups presented better physical and psychosocial health than controls. High volumes of amateur endurance cycling training were associated with better physical health without jeopardizing psychosocial health. The practice of amateur endurance cycling, both in low and high volumes, was associated with better physical and psychosocial health compared with inactivity.     

Effect of endurance training on dental erosion,caries, and saliva

The aim of this investigation was to give insights into the impact of endurance training on oral health, with regard to tooth erosion, caries, and salivary parameters. The study included 35 triathletes and 35 non‐exercising controls. The clinical investigation comprised oral examination, assessment of oral status with special regard to caries and erosion, saliva testing during inactivity, and a self‐administered questionnaire about eating, drinking, and oral hygiene behavior. In addition, athletes were asked about their training habits and intake of beverages and sports nutrition. For saliva assessment during exercise, a subsample of n = 15 athletes volunteered in an incremental running field test (IRFT). Athletes showed an increased risk for dental erosion (P = 0.001). No differences were observed with regard to caries prevalence and salivary parameters measured during inactivity between athletes and controls. Among athletes, a significant correlation was found between caries prevalence and the cumulative weekly training time (r = 0.347, P = 0.04). In athletes after IRFT and at maximum workload, saliva flow rates decreased (P = 0.001 stimulated; P = 0.01 unstimulated) and saliva pH increased significantly (P = 0.003). Higher risk for dental erosions, exercise‐dependent caries risk, and load‐dependent changes in saliva parameters point out the need for risk‐adapted preventive dental concepts in the field of sports dentistry.     

Block periodization of strength and endurance training is superior to traditional periodization in ice hockey players

Team sports like ice hockey require high levels of performance in numerous physical characteristics such as strength, power, and endurance. As such, training is associated with a potential interference effect. The present study randomized well‐trained ice hockey players into a block periodization group (BP; n = 8), focusing on the development of either strength and power or endurance on a weekly, undulating basis, and a traditional group (TRAD; n = 8), performing a mixed training model, with simultaneous focus of strength, power, and endurance training every week. During the 6‐week intervention, the two groups performed equal volumes and intensities of both strength, power, and endurance training. BP led to larger improvements than TRAD in knee extension peak torque at 180° s^?1 (6.6 ± 8.7 vs ?4.2% ± 6.3%, respectively; P < 0.05) and maximal oxygen uptake (5.1 ± 3.3 vs 1.1% ± 3.5%, respectively; P < 0.05). There was also a trend toward larger improvements in BP than TRAD in peak torque in knee extension at 60° s^?1 (2.1 ± 2.5 vs ?0.1% ± 2.5%, respectively; P < 0.1, effect size = 0.83) and mean power output during a 30‐s cycling sprint (4.1 ± 2.5 vs ?0.3% ± 5.9%, respectively; P < 0.1, effect size = 0.89). Overall, BP exhibited a moderate to large effect size for all these variables compared to TRAD. The present study suggests that block periodization of strength and endurance training induces superior adaptations in both strength and endurance capacities in well‐trained ice hockey players compared to traditional mixed organization, despite similar training volume and intensity.     

Assessment of the effect of endurance training on left ventricular relaxation with magnetic resonance imaging

The purpose of the study was to assess the effect of endurance training on the early diastolic global and regional left ventricular (LV) relaxation with three magnetic resonance imaging (MRI) techniques. Fourteen subjects were examined with MRI before and after 3-month endurance training. Global early diastolic LV myocardial relaxation was assessed with mitral flow velocity mapping and regional LV early myocardial relaxation with myocardial tagging. LV end-diastolic and end-systolic volumes and mass were assessed with cine Magnetic resonance imaging (MRI). Mitral flow velocity mapping analysis revealed that the time to peak early filling shortened after training (before 112+/-32 ms, after 97+/-21, P<0.05), indicating more rapid global early myocardial relaxation. LV mass increased (97+/-19 g, 105+/-18, P<0.01) and end-systolic volume decreased (47+/-11 mL, 42+/-13, P<0.05). According to myocardial tagging analysis early myocardial relaxation in the septum and in the LV lateral wall increased (P<0.05). Regional tagging analysis showed enhanced myocardial relaxation in the basal septum (P<0.05). Global and regional LV early diastolic relaxation improved and physiological LV hypertrophy was found after the exercise training period for 3 months in healthy sedentary subjects.     

Pregnancy in endurance athletes

The purpose of the present study was to examine pregnancy and delivery among Finnish endurance athletes at the national top level. A questionnaire concerning first. pregnancy was sent to 30 Finnish endurance athletes who had been at national top level in cross-country skiing, running, speed-skating or orienteering. Data on labour were collected retrospectively through a questionnaire and from the diaries in the hospital concerned. The next primipara in the diaries formed a member of the control group. Twenty-three athletes (77%) had regular menstrual cycles, seven (23%) had irregularities, and four of them had received hormonal treatment for this. Seven athletes (23%) had experienced spontaneous abortion during the first trimester in previous pregnancy. Sixteen (53%) did not notice any change in their exercise performance, three (10%) subjectively felt themselves to be in a better physical condition, and seven (23%) felt themselves to be in a worse condition than before the pregnancy. Four did not respond on the question. After delivery, 18 athletes continued to compete, the median interval being 8.2 months (range 2–24 months). Two of them (11%) achieved a better condition than before the pregnancy, 11 (61%) reached the same level and five (28%) did not achieve the same performance level. There were no significant differences in labour parameters between the athletes and controls. Endurance training had no harmful side-effects on the pregnancies or deliveries of the athletes. The effect of pregnancy on exercise performance is individual.