场地自行车4 000 m追逐赛不同起动方式摄氧动力模型的分析

目的：研究4 000 m场地自行车运动VO2反应,及前15 s高功率起动对运动成绩的影响。方法：11名男子自行车运动员在功率车上进行递增负荷试验和两种不同起动强度的4 000 m运动。首先进行前60 s平均功率（128±2）%MAP即（501.7±41.9）w强度对照模式运动;5 h后进行模拟模式运动,强度在第8~10 s达到最高值235%MAP（928.3±77.6）w,后逐步下降,15 s时至平均功率（421.9±40.1）w,维持15~60 s。60 s之后两组均进行自由速度模式,强度控制在380~420 w之间。结果：整个测试过程模拟组较对照组平均功率高19 w左右,有统计学差异。模拟组15~60 sVO2高于对照组,模拟组15s~60sVO2高于对照组,而AOD却低于对照组,对整个运动表现有促进作用。结论：4 000 m场地自行车运动前15 s高输出功率可伴随着更快的VO2反应而不是单一归于节省时间理论,并可促进中等距离自行车计时运动员的摄氧动员能力。     

艾灸预处理对运动后心率和血压变化的观察

目的：通过对华南师范大学体育学院大一（07级）学生进行艾灸（足三里穴）预处理，来观察艾灸预处理前受试者运动后血压、心率与艾灸预处理后受试者运动后血压、心率的变化，从而探讨艾灸预处理对于运动后心率和血压的影响。方法：在运动前用血压计测定受试者安静时的血压和心率，随后受试者在跑台周Bruce方法进行逐级递增负荷运动，当受试者运动到力竭后测定受试者运动后即刻、运动后15min、运动后30min的血压、和心率。在运动当天后的一星期内对受试者进行艾灸（足三里穴）预处理，在艾灸一星期以后受试者再次进行跑台BRUCE方法逐级递增负荷运动，测定受试者运动前安静时、运动后即刻、运动后15min、运动后30min的血压和心率。结果：（1）收缩压在艾灸预处理前后运动后15min有显著性差异；在安静时、运动后即刻和运动后30min没有显著性差异。（2）舒张压在艾灸预处理前后安静状态和运动后30min有显著性差异；在运动后即刻和运动后15min没有显著性差异。（3）心率在艾灸预处理前后均没有显著性差异。结论：艾灸预处理在安静时和运动后恢复期都有一定的降压作用,也可能与艾灸消除运动性疲劳有一定的关系。     

自行车运动员进行功率自行车3种递增负荷运动实验比较有氧耐力研究

目的:通过40名自行车专业运动员在功率自行车上进行3种递增负荷运动实验比较有氧耐力.方法:40名自行车运动员(男21,女19)在功率自行车上进行有氧力竭运动,分别采用3 min递增法、1 min递增法和线性递增法进行运动负荷递增,用Oxyam Pro运动心肺功能仪观察最大耗氧量(VO2max)、心率(HRmax)、呼吸商(RQ)等指标,运动前、后采集血乳酸(Lac).结果:3种递增负荷运动实验的VO2max、HRmax指标无显著性差异(P>0.05),3种实验的RQ、Lac指标差异无显著规律性.结论:自行车运动员进行功率自行车3种递增负荷运动实验比较有氧耐力没有统计学差异,3种递增负荷运动实验均可作为功率自行车进行有氧耐力测试的方法.     

运动后低氧暴露对血液流变学及红细胞形态的影响

研究目的：观察常氧运动后低氧暴露情况下血液流变学及红细胞形态的变化。研究方法：8名受试者以75％ VO2max强度分别完成2次1h蹬功率自行车运动，间隔1周。第1周受试者以75％ VO2max强度蹬功率自行车1h后即进入低氧室内(氧气浓度：15．4％，相当于海拔2500m)休息30min。第2周同一时间，受试者以同等负荷运动1h后常氧环境休息30min。每次实验分别于安静时、运动后即刻、运动后30min采取静脉血5ml，测血液流变学变化和扫描电镜(SEM)下观察红细胞形态变化。结果：运动后血液粘度升高，红细胞变形能力下降，红细胞形态由双凹圆盘状变为单侧凹陷另一侧隆起似礼帽状的I型口形红细胞。结论：运动后低氧暴露不利于血液流变学及红细胞形态的恢复。     

优秀短距离自行车运动员无氧代谢能力特征研究

目的:比较不同性别和训练水平运动员无氧能力的差异,探讨短距离自行车运动员高能磷酸原供能、糖酵解供能和混合无氧供能能力的特征。方法:对16名优秀短距离自行车运动员进行10s(女)、15s(男)、30s和60s的无氧功测定,测定运动后即刻、运动后3min恢复心率和血乳酸。结果:1)磷酸原代谢能力表现出明显的性别差异,男运动员最大功率、相对最大功率、平均功率、相对平均功率、最大圈数都明显高于女运动员;2)30s和60s两种测试中,运动员爆发力表现出相同水平,但糖酵解代谢持续供能能力随运动时间的延长而明显下降;3)男子优秀运动员组15s无氧功最大功率、平均功率明显高于普通组。男、女最大圈数大于普通组,达到最大圈数时间小于或等于普通组;4)男子优秀组运动员30s、60s平均功率高于普通运动员组。女子优秀运动员组30s、60s平均功率、最大圈数明显高于普通运动员组,60s最大功率明显高于普通运动员组(P<0.05)。结论:1)优秀短距离自行车运动员具有较强的磷酸原代谢能力,男运动员明显强于女运动员;2)较强的糖酵解代谢能力是短距离自行车运动员无氧代谢能力的特征;3)评定磷酸原系统能力时,男、女运动员都使用10s无氧功测试为好;4)不同水平运动员的无氧代谢能力表现出明显差异,优秀运动员组强于普通运动员组。     

急性高强度间歇运动和中等强度持续运动对2型糖尿病患者餐后血糖、胰岛素和炎症因子的影响

目的：对比高强度间歇运动(high intensity interval training,HIIT)和中等强度持续运动(moderate intensity continuous training,MICT)对30～50岁男性2型糖尿病(type 2 diabetes,T2D)患者餐后血糖控制和炎症因子的影响。方法：14位男性T2D受试者[年龄：(42.6±6.5)岁]进行3次交叉随机自身对照试验,每次干预均在早餐后1 h进行,分别为：1)HIIT,高强度运动以90%V O_2max强度骑功率车7组×1 min/组,低强度运动以30%V O_2max强度骑功率车7组×2 min/组,热身以60%V O_2max强度骑功率车4 min,恢复以40%V O_2max强度骑功率车5 min;2)MICT,以50%V O_2max强度持续骑功率车30 min;3)安静对照(CON)在功率车上静坐30 min,每次干预间隔10天。受试者分别在运动前、运动后即刻和运动后1 h 3个时间点抽取静脉血...     

湿热环境下运动对人体血尿素、血乳酸和电解质的影响

通过对湿热环境下机体血液成分变化特点的实验,试图揭示湿热环境下运动的身体适应,为训练提供相应的理论依据。随机抽取某大学男生30名,平均年龄(21.3±1.1)岁。实验选择第二军医大学湿热环境训练实验室,环境温度控制在39℃,相对湿度为80%。实验历时9 d,分为测试阶段和训练阶段:测试阶段在训练前、后1 d分别进行12 min功率自行车测试,2次测试前、后经上肢静脉取血(在肛温指标测试后即刻进行);训练阶段周期为7 d,运动负荷为:踏步机徒手踏步15 min,艾威BC4730-52型功率自行车无阻力运动15 min,艾威BC8500型功率自行车调至10LEVEL-280WATT/H运动15 min。结果显示:与第1次、第2次测试前相比,2次测试后血清尿素(BU)、乳酸(La)、[K+]和[Ca2+]均显著升高(P<0.05),[Cl-]显著下降(P<0.05);[Na+]在第2次测试后显著升高(P<0.05)。经过7 d热习服训练,第2次测试前较第1次测试前相比,BU和[Na+]显著升高(P<0.05),La浓度显著下降(P<0.05);第2次测试后同第1次测试后相比,BU、[Na+]、[K+]和[Ca2+]显著升高(P<0.05)。结果表明:经过7 d间断性反复热暴露运动后,机体蛋白质代谢供能有所回降;La清除能力得到提高;血液电解质各项指标发生不同程度变化,但均处于正常生理范围及人体耐受范围内;且运动能力及自我感受得到改善,说明习服训练有利于机体新的热反应动力定型建立。     

场地短距离自行车大强度骑行中的疲劳定量分析

目的：对场地自行车不同传动比下大强度骑行过程中功率、频率变化进行测评,分析传统疲劳指数、频率指数和净疲劳指数在疲劳评价中的应用价值。方法：10名男子短距离自行车运动员分别使用50：12和50：13两种传动比进行两次200m俯冲骑行测试,使用SRM自行车专用功率记录仪采集骑行全程的功率和踏蹬频率,分别计算传统疲劳指数、频率指数和净疲劳指数。结果：运动员完成200m俯冲骑行到达终点前30s过程中,功率、频率前7s同时逐渐增加,8-11s功率增加但频率维持原来水平,功率在12-15s左右达到最大,此时频率约为130rpm左右,随后可见频率仍在增加,但功率逐步降低。场地自行车大坡俯冲骑行过程中,传统疲劳指数明显高于净疲劳指数,两者计算结果的差异来自与是否将频率变化包括在内。结论：净疲劳指数较传统疲劳指数更好地反映了场地自行车骑行中的功率-频率关系,并能描述不同速度下的疲劳程度。运动员可以通过适度增加传动比,降低频率来提高200m计时赛运动成绩。     

SRM功率自行车模拟场地原地起动训练的研究

目的：通过对SRM功率自行车使用不同档住无氧测试结果的比较，并与场地原地起动训练结果对比，对自行车运动员原地起动能力的实验室测试、评定方法进行探讨。方法：8名优秀男子短距离自行车运动员使用SRM功率自行车9～13档进行15s起动测试和场地166m原地起动训练，对测试结果进行比较、分析。结果：用SRM功率自行车在选择不同档住进行测试时，Pmax除了在9～10、10～11、11～12之间没有显著性差异之外，其余各档住之间都有显著性差异。SRM功率自行车11档测出的TPmax、TCmax、Cmax结果与场地测试结果之间无显著性差异。结论：1）运动员最大功率和总功率输出水平是运动能力的基础，专项最大功率的出现取决于环境阻力和选取与环境阻力相匹配的最佳传动比，阻力或频率的改变都会使人体输出功率改变。2）使用SRM功率自行车进行测试时，应根据运动员的训练水平不同，选取合适的档住，在实验室模拟场地原地起动166m训练，11档是最合适的。     

中老年人在FATmax强度下运动时心血管风险指标的变化

目的探讨55~65岁中老年人在最大脂代谢强度下(FATmax)运动时,不同时间点上心血管风险指标的变化,为中老年人制定有效、安全的减脂运动处方提供一定的理论指导。方法招募55~65岁中老年人50名,通过递增运动负荷试验(GXT试验)测试出每位受试者FATmax时的心率。间隔3天以上,使每位受试者心率控制在FATmax对应的靶心率范围内持续运动30~60 min。每5 min测量一次血压,心率通过运动心电图实时监测。研究分析运动第15、30、45和60 min等不同时间点上心血管风险指标的变化。结果 (1)在FATmax强度下持续运动到30min时间点上的41名受试者,超重组的收缩压变异系数与正常体重组相比,有显著性差异(P<0.05);持续运动15、30 min时间点上,女性SBP、脉压上升水平均低于男性,在30 min时间点上两者有显著性差异(P<0.05)。(2)在FATmax强度下持续运动60 min的21名受试者中,14名男性在运动45、60 min时间点上DBP基本保持不变,SBP、脉压、RPP均比安静状态显著升高(P<0.01),2个时间点之间相比并无显著性差异。7名女性在运动45 min和60 min时间点上比较,SBP、脉压、RPP有显著性降低(P<0.05),收缩压标准差有显著性升高(P<0.05);运动45 min时女性与男性相比,舒张压有显著性下降(P<0.05)。(3)运动60 min时间点上,男、女性SBP反应异常率分别达到21.43%和71.43%。结论 55~65岁中老年人在FATmax下持续运动30 min是安全的,持续运动60 min时女性发生心血管风险的可能性高于男性。     

体育锻炼延缓老年人认知衰退量效关系的专家共识

检索国内外5个大型电子数据库中关于体育锻炼干预老年人认知功能的随机对照试验,按英国牛津循证医学中心认定的证据水平评价标准,对纳入文献进行分级,统计与分析体育锻炼各变量对认知功能的影响效果,形成体育锻炼延缓老年人认知衰退量效关系的专家共识。结果显示:有氧运动对执行功能的干预效果较好,推荐方案为每周3次,中等强度,每次30~60 min,锻炼周期为12~24周;抗阻运动对执行功能干预效果较好,推荐方案为每周锻炼2次,中、高强度,每次60 min,锻炼周期为24周;多成分运动对整体认知、记忆、执行功能均具有良好的干预效果,推荐方案为每周锻炼3~4次,中等强度,每次30~60 min,锻炼周期为12~24周;中国民族传统体育对整体认知功能干预效果较好,推荐方案为每周锻炼3~5次以上,中等强度,每次锻炼30~60 min,锻炼周期为12~24周。     

Response of brain-derived neurotrophic factor to combining cognitive and physical exercise

Purpose: Brain-derived neurotrophic factor (BDNF) is well known for its potential to promote brain plasticity. It has been proposed that combining cognitive and physical exercise (CCPE) may have the potential to generate more synergistic benefits in cognitive function than either cognitive exercise (CE) or physical exercise (PE) alone. The purpose of this study was to examine acute responses of peripheral BDNF levels and cognitive performance to CE, PE, and CCPE.

Methods: Thirteen healthy adult men participated in four experimental sessions; a 30-min CE, a 30-min cycling PE at an intensity of 60% peak oxygen uptake, a 30-min CCPE at the same intensity as PE, and a 30-min session of complete rest. Plasma BDNF levels and cognitive performance were measured before and after each session.

Results: Both PE and CCPE significantly increased plasma BDNF levels (p?p?≥?.05), and there was no significant difference in peripheral BDNF levels between PE and CCPE (p?≥?.05). No session induced a significant change in cognitive performance (p?≥?.05).

Conclusions: Our study suggests that CE and PE have different responses of peripheral BDNF levels and that CCPE had no additional or synergistic effect on peripheral BDNF levels compared with PE alone. This study offers further insights into the potential mechanisms underlying the respective roles of CE, PE, and CCPE for peripheral BDNF levels and cognitive performance.     

Fördert ein multidimensionales Gesundheitssportprogramm kognitive und motorische Fähigkeiten im höheren Erwachsenenalter?

Research on successful aging has shown that physical training can have positive effects on cognitive and motor functions in the elderly. The article describes a study involving a 12-week multidimensional exercise program (endurance, strength, flexibility and relaxation) with one session per week which was established for older adults (60 years onwards). Cognitive training (e. g. attention, concentration and memory) was additionally targeted in each exercise session. The exercise program was evaluated by different standardized tests regarding its effects on motor and cognitive performance as dependent variables. In a randomized controlled trial with experimental and waiting control group two points of measurement were conducted. The results showed a significant increase in fitness parameters (endurance, strength and dynamic balance) for the experimental group in contrast to the control group. The expected significant increase for cognitive functions was not found. There is still not enough known about the relationship between cognitive function and physical activity in older adults.     

Exercise and working memory: an individual differences investigation

In the current work we asked whether executive function, as measured by tests of working memory capacity, might benefit from an acute bout of exercise and, more specifically, whether individuals who are lower or higher in working memory to begin with would be more or less affected by an exercise manipulation. Healthy adults completed working memory measures in a nonexercise (baseline) session and immediately following a 30-min self-paced bout of exercise on a treadmill (exercise session). Sessions were conducted 1 week apart and session order was counterbalanced across participants. A significant Session x Working Memory interaction was obtained such that only those individuals lowest in working memory benefited from the exercise manipulation. This work suggests that acute bouts of exercise may be most beneficial for healthy adults whose cognitive performance is generally the lowest, and it demonstrates that the impact of exercise on cognition is not uniform across all individuals.     

Impact of aerobic exercise trials with varied intensity patterns on perceptions of effort: an evaluation of predicted, in-task, and session exertion

Perceptions of effort provide a sense of momentary exertion during exercise, but may have value when considered prior to and after exercise. The purpose of the present study was to determine the relationship between perceived exertion assessed before, during, and after trials of aerobic exercise fixed for total work but varied on intensity patterns. Twenty participants completed five trials of treadmill exercise that included planned intensity variations every 10 minutes to result in the same total work. Perceived exertion was taken before, during, and after exercise. Analyses confirmed each trial was similar in terms of average speed and heart rate (P > 0.05). Predicted and session exertion results indicated that the steady exercise bout was perceived as easier than many trials of varied speed (P < 0.05). Trials including an intense segment in the middle or end of the session were perceived as more difficult than sessions that varied intensity otherwise or remained constant. Similarly, trials that remained constant during the 30-minute period were perceived as less aversive than most other trials. These findings suggest that exercise sessions involving a steady intensity throughout are viewed as less taxing than sessions with variable intensity, especially when compared to sessions that conclude with a higher intensity finish.     

Exhaled nitric oxide in single and repetitive prolonged exercise

This study was performed to determine the influence of single and repetitive exercise on nitric oxide (NO) concentration in the lung. Exhaled NO concentration (FE(NO)) was measured during a constant-flow exhalation manoeuvre (170 ml x s(-1), against a 10 cmH2O resistance) in healthy individuals (a) during and after a 100-min square-wave exercise of between 25 and 60% of maximal power output (n = 18) and (b) before and after five successive prolonged exercises (90-120 min, 75-85% of maximal heart rate) separated by 48 or 24 h (n = 8). The FE(NO0.170) was decreased during and after the 100-min exercise test (mean +/- s(x): 58.5 +/- 3.7% and 76.7 +/- 5.2% of resting value at 90 min of exercise and 15 min post-exercise, respectively; P < 0.05). The five successive exercise sessions induced a similar post-exercise FE(NO0.170) decrement (73.1 +/- 2.9% of resting value 15 min post-exercise), while basal FE(NO0.170) values were not different between the five sessions (P > 0.05). These results suggest that prolonged exercise induces a reduction in NO concentration within the lung that lasts for several minutes after the end of exercise. However, repetitive exercises (at least every 24 h) allow complete NO recovery from one session to another. The implication of such a decrease in NO availability within the lung remains to be clarified.     

Whole-body pre-cooling and heat storage during self-paced cycling performance in warm humid conditions

The aim of this study was to establish the effect that pre-cooling the skin without a concomitant reduction in core temperature has on subsequent self-paced cycling performance under warm humid (31 degrees C and 60% relative humidity) conditions. Seven moderately trained males performed a 30 min self-paced cycling trial on two separate occasions. The conditions were counterbalanced as control or whole-body pre-cooling by water immersion so that resting skin temperature was reduced by approximately 5-6 degrees C. After pre-cooling, mean skin temperature was lower throughout exercise and rectal temperature was lower (P < 0.05) between 15 and 25 min of exercise. Consequently, heat storage increased (P < 0.003) from 84.0+/-8.8 W x m(-2) to 153+/-13.1 W x m(-2) (mean +/- s(mean)) after pre-cooling, while total body sweat fell from 1.7+/-0.1 l x h(-1) to 1.2+/-0.1 l h(-1) (P < 0.05). The distance cycled increased from 14.9+/-0.8 to 15.8+/-0.7 km (P < 0.05) after pre-cooling. The results indicate that skin pre-cooling in the absence of a reduced rectal temperature is effective in reducing thermal strain and increasing the distance cycled in 30 min under warm humid conditions.     

Active recovery effects on local oxygenation level during intensive cycling bouts

We hypothesised that the oxygen supply to the fatigued muscles is improved after the recovery with exercise caused by aerobic metabolism in the slow twitch fibres during the recovery period. Ten males performed a 30 s maximum cycling (1st Exercise), followed by a 20 min rest interval (Interval Rest) in which participants were either sitting (No Exercise) or low intensive cycling (Active). Then they again underwent a 30 s bout of maximum cycling (2nd Exercise). The total work of the 2nd Exercise was higher in Active compared to No Exercise (297 ± 14 vs 276 ± 23 J · kg(-1), P < 0.01). After Interval Rest, the muscle oxygenation level (P < 0.05) and blood lactate concentration (P < 0.05) were lower in Active compared to No Exercise. In Active, the total work was higher in the 2nd Exercise than the 1st Exercise (297 ± 14 vs 277 ± 23 J · kg(-1), P < 0.01), and muscle oxygenation levels during the 2nd Exercise were also higher at 10 (P < 0.05) and 15 (P < 0.01) s after the beginning of the exercise. It was suggested that active recovery exercise would manage to increase the muscle oxygenation level, and improve the performance during the 2nd Exercise accompanied with blood lactate control.     

运动后血清和骨骼肌HSP60的关系及对骨骼肌的保护作用

目的探讨运动后血清、骨骼肌HSP60含量变化、相关关系及其对骨骼肌的保护作用。方法26名成人(15男11女)进行60 min的功率脚踏车运动,运动负荷为70%的最大摄氧量(VO2max)。于运动开始30 min,结束后即刻、1、2、8、244、8 h采集血样、股外侧肌活检,检测HSP60、肌酸激酶骨骼肌同工酶(CK-MM)含量。结果血清HSP60和骨骼肌内HSP60含量变化是一致的,血清CK的变化相比HSP60的变化是上升的晚,下降的早。结论剧烈运动后HSP60在血清及骨骼肌内含量增加,血清HSP60可能是由骨骼肌细胞分泌。     

Pediatric Obesity and Perceived Exertion: Difference Between Weight-Bearing and Non-Weight-Bearing Exercises Performed at Different Intensities

Excess body weight composes an important limitation to exercise in obese youth. The aim of this study was to compare the perceived exertion of obese adolescents between weight-bearing (WB; running) and non-weight-Bearing (NWB; cycling) exercises performed at moderate (55%VO_2max) and high (75%VO_2max) intensities. Twenty-four obese adolescents were recruited. After assessment of their body composition and physical capacities, they had to complete four isoenergetic exercise sessions: (1) a cycling session performed at 55% of their maximal capacities (NWB-55%); (2) a cycling session set at 75% (NWB-75%); (3) a running session at 55% (WB-55%); and (4) a running session at 75% (WB-75%). Perceived exertion was assessed using a visual scale at regular interval. While no significant difference between WB and NWB modalities was observed, the adolescents expressed a significantly lower rate of perceived exertion (RPE) during exercises at 55%VO_2max (P < 0.0001). An intensity × modality interaction revealed that RPE was lower at 75% VO_2max during NWB exercises (P < 0.05). While obese adolescents expressed lower RPE during exercise at moderate intensity whatever its modality, low level of perceived exertion has been observed during high-intensity exercises and especially during NWB. High-intensity exercise appears well tolerated in adolescents when their body weight is supported.