不同负荷形式的生理生化指标与武警战士的有氧代谢能力评价研究

 目的研究不同负荷形式的生理生化指标变化与武警战士的有氧代谢能力的关系,为有氧代谢能力的评定提供理论和实践依据.方法通过亚极量踏阶运动间接法,测定VO2max(最大摄氧量),选取通过有针对性的有氧耐力训练后,VO2max较高的1组作为实验组,较低的1组作为对照组,对两组战士分别进行极量负荷和定量负荷实验,测定负荷后和某负荷阶段的有关生理生化、生理心理指标.结果定量负荷后,实验组的血乳酸(Bla)和心率(HR)值均低于对照组(P＜0.01);负荷后的恢复期,实验组的指标变化情况优于对照组(P＜0.05或P＜0.01),在运动过程中,随着负荷量的增加,实验组的主体感觉(RPE)值低于对照组.极量负荷后,两组间的HR值无显著性差异,实验组的Bla高于对照组.结论不同负荷形式的生理、生化指标的变化能够反映武警战士不同的有氧代谢能力,在选择有氧耐力训练安排中有应用价值.     

HZY-1型高原增氧呼吸器对移居者视网膜的影响

目的:通过使用HZY-1型高原增氧呼吸器负荷运动后观察视网膜动态的方法,评价对初入海拔3700m移居者生理功能的改善状况。方法:选择首次进入海拔3700m20d的某部青年男性12人,均为平原出生,确认健康。使用面罩式增氧呼吸器进行EGM型自行车功量仪负荷运动后(负荷指标:W250,P175次/min~180次/min)10min在简易暗室内小瞳孔下检查眼底,以平原健康青年眼底为标准[1]。10d后,不使用增氧呼吸器进行同负荷量运动后重复检查。结果:使用增氧呼吸器负荷运动后10min,视乳头、视网膜静脉发生轻度(±)充血、怒张改变,视网膜及动脉基本无改变(-),无改变率为100%(12人),不使用增氧呼吸器负荷运动后10min,视乳头呈中度( )充血改变、静脉怒张呈中度( )改变、视网膜渗出呈轻度(±)改变,改变率为100.0%(12人)。结论:使用增氧呼吸器负荷运动后能显著减轻视网膜缺氧性改变。     

运动和腺苷负荷核素心肌灌注显像诊断缺血性心脏病的价值

选择本院不典型胸闷,胸痛患者292例.均行运动或腺苷负荷99Tcm-甲氧基异腈(MIBI)心肌灌注显像,并与2周内冠状动脉(简称冠脉)造影结果比较,以探讨运动和腺苷负荷心肌灌注显像在缺血性心脏病诊断中的价值,现报道如下.     

不同旋转速度背景及认知负荷对视认知早期加工的影响

目的研究不同转速旋转背景条件下,完成不同认知负荷视觉认知任务过程中的视认知早期加工的变化。方法受试者为20名健康右利手大学生,视觉背景分为白色背景与不同转速的模拟星空背景。要求受试者完成不反应、选择区分和选择心算任务,同时记录12导脑电数据。结果各种负荷任务中中央区的P1潜伏期最短,峰值波幅最高;与白色背景相比,各种速度旋转背景下,反应时及P1潜伏期缩短;与白色背景相比,不同旋转背景下完成选择区分及选择心算任务的P1峰值波幅升高。结论不同速度星空旋转背景加速了视觉认知的感知,在高负荷任务下增加启动效应。星空旋转不同角速度主要对区分反应的主动抑制加工过程产生影响。     

静力性负荷与动力性负荷时的心脏效应及其与肌纤维成份的关系

本文通过UCG分别测定11名肌纤维成份不同的青年男子划船运动员在静力性负荷与动力性负荷时相应的心功能指标并加以比较,以探讨上述两种类型负荷对心脏的不同影响;本文还讨论了心功能与肌纤维成份之间是否存在某种内在联系。     

人机交互领域脑力负荷研究进展

人机交互中操作员的脑力负荷关系着系统的运行效率、可靠性及安全性。本文综述了人机交互领域脑力负荷的研究现状,通过4种常见定义及8项测评准则对脑力负荷进行了阐述;分析了主观测量和任务测量2种传统的脑力负荷测量方法;结合文献案例探讨了4种基于神经人因学的脑力负荷生理测量法,并总结了各方法常用的测量指标参数。最后讨论了各种测量方法的优势和局限性,并对该领域的研究提出了见解和展望。     

三种不同方式渐减负荷运动对运动后过量氧耗的影响

为了探讨在渐减负荷运动中不同负荷量对运动后过量氧耗的影响 ,选择了 12名身体健康的体育学部男子大学生 ,在下述不同运动条件下 ,进行功率自行车负荷运动 ,测定吸氧量 (VO2 )、通气量 (VE)、心率 (HR)及血乳酸浓度(La) :(1)通过渐增负荷运动以确定最大功率及最大吸氧量 ;(2 )均以个人最大吸氧量 90 %功率为起点 ,分别进行每分递减 30W、2 0W、10W至 0负荷的 3种不同方式的渐减负荷运动。结果如下 :(1)渐增负荷运动时的最大吸氧量为 2 .81± 0 .12l/min,最大血乳酸浓度为 9.6 5± 1.2mmol/L ;(2 )每分递减 30W的渐减负荷运动时La浓度明显低于每分递减2 0W、10W运动时的值 ;(3)每分递减 10W的运动时VO2 显著高于每分递减 30W、2 0W运动时的值 ;(4)每分递减 30W运动时的VO2 excess与La之间呈低相关 (r=0 .16 7n.s ) ,而每分递减 2 0W和每分递减 10W运动时的VO2 excess与La之间均呈高相关 (2 0W :r=0 .482 ,p <0 .0 5 ;10W :r =0 .76 3,p <0 .0 0 1)。结果表明渐减负荷运动时的递减速度越低 ,其VO2 excess与La浓度相关越密切。     

中国女排运动员不同负荷自行车运动时脑电图研究

<正> 本文通过运动员进行不同负荷功率自行车运动时连续描记脑电波的特点,了解不同负荷对中枢神经系统的影响。对象和方法14名中国著名的女排运动员进行功率自行车运动试验,在300kg m/min1'(准备负荷),600kg m/min 4'(一级负荷),900kg m/min4'(二级负荷),在600kg m/min和900kg m/min之间休息2'。整个实验过程中受试的运动员在     

听觉事件相关电位(ERPs)早期和晚期成份的任务负荷效应

目的 比较不同任务负荷的听觉事件相关电位（ERPs,event-related potentials)，以探讨听觉ERPs各种成份的任务负荷效应。方法 被试者为12名右利手正常在校大学生（20－23岁）。要求被试者对4个方位的声音信号进行难度负荷不同的3种作业任务：全反应（AR）、方位区分反应（DR）、音调选择方位式区分反应（SR）。对－t和方差分析统计3种任务的听觉ERPs成份。结果1）SR反应时最长，DR次之，AR最短；2）早期成份的任务负荷效应：P1波幅随负荷的增加进行性增强；AR－ERPs的NI峰值相近，均高于SR（T）－ERPs；DR－ERPs与SR（T）－ERPs中前脑区的P2波幅无明显差异，均显著低于AR－ERPs，P2的潜伏期随负荷的增加明显缩短；3）晚期成分的任务负荷效应；随任务负荷的增加，N2（N2a/N2b),P3和SW波幅明显增强。结论 听觉ERPs早期成份和晚期成份均有明显的任务负荷效应，晚期成份的任务负荷效应可能与早期的警觉激活程度相关联。     

歼击机飞行员脑力负荷评价模型的研究

目的 评定飞机飞行品质,建立“歼击机飞行员脑力负荷评价模型”。方法 在歼－Ａ和歼－１两种不同飞机的地面飞行模拟器上,由飞过该两种飞机的飞行员进行测试,对评价脑力负荷的主观评价法,主任务评价法,次任务评价法,生理评价法和综合评价法共７个指标用显著性测验进行选择。结果 ５个评价指标当选,根据该５个指标的权重建立了“歼击机飞行员脑力负荷评价模型”,并在歼－Ｃ飞机地面模拟器上进行了验证。结论 结果与试飞员     

耐力、力量、速度性项目优秀运动员和无训练青年左心形态功能之对比研究

应用超声心动图方法对耐力、力量、速度三组84名优秀运动员及常人对照组的心脏作了对比研究。结果提示:三类运动员心脏结构功能的特点不同;耐力运动员心脏结构功能变化最为明显。     

Effects of an entire season on physical fitness changes in elite male handball players

PURPOSE: Fifteen elite male handball players were studied to examine the effects of an entire season of play on physical fitness and throwing velocity. METHODS: One repetition maximal bench press (1RMBP), jumping explosive strength, power-load relationship of the leg and arm extensor muscles, 5- and 15-m sprint running time, endurance running, and handball throwing velocity (standing and three-step running throw) were assessed on four times (T1, T2, T3, and T4), during a 45-wk season. Individual volumes and intensities of training and competition were quantified for 11 activities. RESULTS: From T1 to T3, significant increases occurred in free fatty mass (1.4%), 1RMBP (1.9%), standing throwing velocity (6.5%), and three-step throwing velocity (6.2%). No significant changes were observed throughout the season in endurance running and explosive strength-related variables. Significant correlations (P < 0.05-0.01) were observed between strength training time and changes in standing throwing velocity as well as between high-intensity endurance training time and changes in endurance running. In addition, linear inverse relationships were observed between low-intensity endurance training time and changes in muscle power output of the lower extremities. CONCLUSION: The handball season resulted in significant increases in maximal and specific strength of the upper-extremity but not in the lower-extremity actions. The correlations observed suggest that training time at low intensity should be given less attention, whereas the training stimuli for high-intensity endurance running and leg strength training should be given more careful attention in the full training season program.     

Effects of an entire season on physical fitness in elite female handball players

PURPOSE: Sixteen elite female handball players were studied to examine the effects of an entire season on anthropometric characteristics, physical fitness, and throwing velocity. METHODS: One-repetition-maximum bench press (1RMBP), jumping explosive strength, power-load relationship of the leg and arm extensor muscles, 5- and 15-m sprint running time, endurance running, and handball throwing velocity were assessed in four periods. Individual volumes and intensities of training and competition were quantified for 11 activities. RESULTS: During the season, significant increases (P < 0.05-0.01) occurred in fat-free mass (1.8 +/- 1.2%), 1RMBP (11 +/- 7.4%), bench press (12-21%) and half-squat (7-13%) muscle power output, vertical jumping height (12 +/- 7.2%), throwing velocity (8 +/- 5.9%), and a significant decrease in percent body fat (9 +/- 8.7%). No changes were observed in sprint and endurance running. Significant correlations (P < 0.05-0.01) were observed between time devoted to games and changes in velocity at submaximal loads during bench press actions, as well as between changes in muscle velocity output of the upper and lower extremities and changes in throwing velocity. Changes in percent body fat or body mass correlated (P < 0.01) positively with changes in maximal strength and muscle power. CONCLUSION: The handball season resulted in significant increases in anthropometric characteristics, physical fitness, and throwing velocity. The correlations observed suggest the importance of including explosive strength exercises of the knee and elbow extensions. Special attention may be needed to be paid to the mode of body fat loss, to increase endurance capacity without interfering in strength gains. Official and training games may be an adequate stimulus for enhancing certain physical fitness characteristics in female elite handball players.     

Strength and endurance in elite football players

We aimed to improve the physical capacity of a top-level elite football team during its pre-season by implementing a maximal strength and high-intensity endurance training program. 21 first league elite football players (20-31 yrs, height 171-194 cm, mass 58.8-88.1 kg) having recently participated in the UEFA Champions' League, took part in the study. Aerobic interval-training at 90-95% of maximal heart rate and half-squats strength training with maximum loads in 4 repetitions × 4 sets were performed concurrently twice a week for 8 weeks. The players were not familiar with maximal strength training as part of their regular program. Maximal oxygen uptake (VO(2max)) increased 8.6% (1.7-16.6) (p<0.001), from 60.5 (51.7-67.1) to 65.7 (58.0-74.5) mL · kg (-1) · min (-1) whereas half-squat one repetition maximum increased 51.7% (13.3-135.3) (p<0.001), from 116 (85-150) to 176 (160-210) kg. The 10-m sprint time also improved by 0.06 s (0.02-0.16) (p<0.001); while counter movement jump improved 3.0 cm (0.1-6.2) (p<0.001), following the training program. The concurrent strength and endurance training program together with regular football training resulted in considerable improvement of the players' physical capacity and so may be successfully introduced to elite football players.     

Does endurance or sprint training influence the perception of the optimal pedalling rate during submaximal cycling exercise?

The purpose of this study was to investigate the effects of endurance and sprint training on the perception of the optimal pedalling rate during a submaximal cycling exercise. Six subjects specialized in endurance activities and 6 subjects trained in sprinting activities used the model of bicycling at various pedalling rates with the same power output (150W) on a cycle ergometer. Individual 2nd order polynomial relationships were determined between oxygen consumption (VO(2)) and velocity and between rate of perceived exertion (RPE) and velocity. Optimal velocity, with respect to minimum of VO(2) (OV(VO2)) and to minimum of RPE (OV(RPE)), were calculated for all subjects, respectively. The close similarity found between the VO(2)-velocity and the RPE-velocity curves confirmed that the overall RPE was mainly influenced by the central factor. As OV(RPE) and OV(VO2) were not significantly correlated and as OV(RPE) was significantly higher than OV(VO2), other factors than central may also have influenced the RPE. The significant higher OV(RPE) values (p<0.05) observed in the sprint vs. endurance groups suggested that different training background may have influenced the RPE. These differences could also be explained by a significantly higher OV(VO2) in sprint than in endurance groups, the subjects being sensitive to the pedalling rate for which the energy expenditure is minimal.     

Ammonia threshold--comparison to lactate threshold,correlation to other physiological parameters and response to training

During standard graded exercise, blood lactate and blood ammonia levels increase in parallel and the two thresholds appear at the same relative intensity. The first part of this study aimed at comparing ammonia threshold to lactate threshold with five different graded exercise protocols. A significant difference between the two thresholds was found only in the continuous protocol with 4-min steps in which ammonia threshold appeared at a higher intensity than lactate threshold. The second part of the study investigated the correlation of ammonia threshold to some common physiological measurements. Correlation was significant with lactate threshold, ventilation threshold and endurance time. No correlation was found the anaerobic power, anaerobic capacity measurement and peak VO2. Ammonia threshold was also studied before and after endurance training and sprint training. The 8-week endurance training program was able to delay the appearance of ammonia threshold, but not the 8-week sprint training program. Findings in this study demonstrate that ammonia threshold is a physiological parameter that should be recognized and has potential to be applied for the evaluation of exercise capacity and the effectiveness of endurance training programs.     

Neural, metabolic, and performance adaptations to four weeks of high intensity sprint-interval training in trained cyclists

The purpose of this study was to investigate the effects of short-term, high-intensity sprint training on the root mean squared (RMS) and median frequency (MF) derived from surface electromyography (EMG), as well as peak power, mean power, total work, and plasma lactate levels in trained cyclists when performed concurrently with endurance training. Seventeen trained cyclists were randomly assigned to a sprint training (S) group (n = 10, age 25 +/- 2.0 y) or a control (C) group (n = 7, age 25 +/- 0.5 y). Sprint training was performed bi-weekly for four weeks, comprising a total of 28 min over the training period. EMG measurements were taken before and after training during a series of four 30-s sprints separated by four minutes of active recovery. Plasma lactate, peak power, mean power, and total work were measured during each sprint bout. Following sprint training a significant increase occurred in the RMS of the vastus lateralis with a decrease in MF of the same muscle. Values for the vastus medialis did not change. Pre training exercising plasma lactate values were higher (p < 0.05) in C compared to S, but did not change with training. Exercising plasma lactate values increased (p < 0.05) from pre to post training in S, but were not different from C post training. Total work output increased from pre to post in S (p = 0.06). Peak power, mean power, and V.O (2)max increased (p < 0.05) pre to post training in S and C, indicating C was not a true control. In conclusion, these data suggest that four weeks of high-intensity sprint training combined with endurance training in a trained cycling population increased motor unit activation, exercising plasma lactate levels, and total work output with a relatively low volume of sprint exercise compared to endurance training alone.     

The relationship between carbon dioxide sensitivity and sprint or endurance performance in young swimmers.

There has been some evidence that extremes of CO2 sensitivity can indicate an individual's potential for sprint or endurance athletic performance. This study examined the responses to CO2 rebreathing, and previously validated sprint and endurance tests by subjects who were involved in regular, but not intensive, swimming training. The aim was to determine whether subjects with low CO2 sensitivity might perform better on endurance tests, whilst those subjects with high CO2 sensitivity would be more successful in the sprint tests. Initially, 168 young (mean mean(s.d.) age = 12.4(2.1) years) swimmers were measured using a modified version of the Read CO2 rebreathing technique. From this sample, 17 high (mean means(s.d.) = 2.24(0.39) 1 min-1 mmHg-1) CO2 responders were matched by gender, age, height, weight and FVC with 17 low (mean means(s.d.) = 0.57(0.19) 1 min-1 mmHg-1) responders. Each of these 17 pairs underwent two sprint tests (10 s Tri-level alactic power, 50 m run) and two endurance tests (PWC170, 1.6 km run) in order to determine whether any differences existed between the two groups and the sprint and endurance parameters. The subjects remained unaware of their results of the rebreathing test throughout testing. A dependent t test was then used to compare the results collected from each group. The low CO2 responders recorded a significantly faster 1.6 km run time, but were not superior on the PWC170 ergometer test, than the high CO2 responders. The high CO2 responding group recorded significantly higher results on the 10 s alactic power test, but not the 50 m sprint run, than the low responders. Hence, further study is required to ascertain underlying causes as to why significant differences occurred with CO2 rebreathing, the 1.6 km run and the 10 s alactic power test, but not with the PWC170 and the 50m sprint run.     

Human torque velocity adaptations to sprint, endurance, or combined modes of training.

We had groups of athletes perform sprint and endurance run training independently or concurrently for 8 weeks to examine the voluntary in vivo mechanical responses to each type of training. Pre- and posttraining angle-specific peak torque during knee extension and flexion were determined at 0, 0.84, 1.65, 2.51, 3.35, 4.19, and 5.03 radian.sec-1 and normalized for lean body mass. Knee extension torque in the sprint-trained group increased across all test velocities, the endurance-trained group increased at 2.51, 3.34, 4.19, and 5.03 radian.sec-1, and the group performing the combined training showed no change at any velocity. Knee flexion torque of the sprint and combined groups decreased at 0.84, 1.65, and 2.51 radian.sec-1. Knee flexion torque in the sprint-trained group also decreased at 0 radian.sec-1 and in the combined group at 3.34 radian.sec-1. Knee flexion torque in the endurance-trained group showed no change at any velocity of contraction. Mean knee flexion:extension ratios across the test velocities significantly decreased in the sprint-trained group. Knee extension endurance during 30 seconds of maximal contractions significantly increased in all groups. Only the sprint-trained group showed a significant increase in endurance of the knee flexors. These data suggest that changes in the voluntary in vivo mechanical characteristics of knee extensor and flexor skeletal muscles are specific to the type of run training performed.     

Strength/endurance training versus endurance training in congestive heart failure

PURPOSE: The aim of this study was to compare the effects of endurance training alone (ET) with combined endurance and strength training (CT) on hemodynamic and strength parameters in patients with congestive heart failure (CHF). METHODS: Twenty male patients with CHF were randomized into one of two training regimens consisting of endurance training or a combination of endurance and resistance training. Group ET had 40-min interval cycle ergometer endurance training three times per week. Group CT combined endurance and strength training with the same interval endurance training for 20 min, followed by 20 min of strength training. Left ventricular function was assessed at baseline and after 40 training sessions by echocardiography and radionuclide ventriculography. Work capacity was measured with cardiopulmonary exercise test (CPX) and lactate determination. Strength was measured with an isokinetic dynamometer. RESULTS: After 40 sessions, the ET group improved functional class, work capacity, peak torque, and muscular endurance. However, peak O2 remained unchanged. Left ventricular ejection fraction (LVEF) and fractional shortening (FS) decreased, whereas left ventricular end-diastolic diameter (LVED) increased. The CT group improved NYHA score, working capacity, peak O2, and peak lactate; peak torque and muscular endurance, LVEF, and FS increased, whereas LVED decreased. Compared with ET, CT was significantly (P < 0.05) better in improving LV function.CONCLUSION: Combined endurance/strength training was superior to endurance training alone concerning improvement of LV function, peak VO2, and strength parameters. It appears that for stable CHF patients, a greater benefit can be derived from this training modality.