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1.
Seven elite male cross-country skiers trained for 3 weeks at an altitude of 1900 m. Haemoglobin concentration ([Hb]), haematocrit (Hct) (obtained from venous blood), maximal oxygen uptake (VO2 max) and energy expenditure during a standard submaximal workload were measured before and after training at altitude, and 1 year later while training at sea level (control). Both [Hb] and Hct increased significantly, and the skiers with the lowest initial [Hb] and Hct experienced the largest increases during training at altitude. The increase in blood lactate (BLa) concentration (using haemolysed capillary blood) during a standard submaximal exercise test was significantly lower after training at altitude than before it or 1 year later (control). A significant correlation was found between the magnitude of increase in [Hb] and Hct and the difference in the lactate response to the standard submaximal workload pre- and post-altitude training. Although VO2 max remained unchanged, lower BLa concentration during the submaximal test probably reflects an improved ability to exercise at higher submaximal workloads shortly after training at altitude compared with pre-altitude training. It is suggested that subjects with low initial [Hb] and Hct improve their aerobic performance capacity most during altitude training.  相似文献   

2.
T'ai Chi Chuan (TCC) is a widely practiced Chinese martial art said to physically develop balance and coordination as well as enhance emotional and mental health. TCC consists of a series of postures combined into a sequential movement providing a smooth, continuous, low-intensity activity. The purpose of this study was to examine the ventilatory and cardiovascular responses to the Long Form of Yang's style TCC. In addition, the subjects' TCC responses were compared to their ventilatory and cardiovascular responses during cycle ergometry at an oxygen consumption (VO2) equivalent to the mean TCC VO2. Six experienced (M = 8.3 yrs) male TCC practitioners served as subjects with data collected during the Cloud H and movement of the TCC exercise. Significantly (p less than .05) lower responses for ventilatory frequency (Vf) (11.3 and 15.7 breaths.min-1), ventilatory equivalent (VE/VO2) (23.47 and 27.41), and the ratio of dead space ventilation to tidal volume (VD/VT) (20 and 27%) were found in TCC in comparison to cycle ergometry. The percentage of minute ventilation used for alveolar ventilation was significantly higher during TCC (p less than .03) than cycle ergometry, with mean values of 81.1% and 73.1%, respectively. Cardiac output, stroke volume, and heart rate were not significantly different between TCC exercise and cycle ergometry at the same oxygen consumption. We concluded that, during TCC, expert practitioners show significantly different ventilatory responses leading to more efficient use of the ventilatory volume than would be expected from comparable levels of exertion on a cycle ergometer.  相似文献   

3.
Cardiorespiratory and body composition changes were evaluated in 25 sedentary females, aged 18 to 30 years, following 12 weeks of aerobic dance training (3 days a week, 45 min a session). Fifteen subjects, from the same population, comprised a control group: they maintained their normal activity and dietary habits over the course of the study. Analysis of variance of the values for selected cardiorespiratory responses revealed that the aerobic dance programme produced training effects in the experimental group. These training effects were indicated by significant improvements in O2 pulse, VE, heart rate and perceived exertion during submaximal exercise. Significant improvements were also noted in VO2 max, maximal O2 pulse, VE max, maximal heart rate and maximal running time on the treadmill. Additionally, increases in lean body mass and body density, together with decreases in percentage body fat and the sum of four skinfold thicknesses were found to be significant for the experimental group. No significant improvements in any of these variables were found for the control group. It was concluded that this 12-week aerobic dance programme was successful in promoting beneficial changes in cardiorespiratory fitness and body composition.  相似文献   

4.
Abstract

The inflammatory responsive cytokine interleukin-6 (IL-6) helps regulate immune responses to exercise. Evidence suggests that increases in IL-6 are related to exercise duration and intensity. However, the moderating effect of sex and underlying mediators have received limited attention. We compared plasma IL-6 responses to two cycling tasks with a resting control in young male (n = 12) and female (n = 12) recreationally active adults. Both 45 min tasks comprised an incremental test, either maximal or submaximal, followed by steady-state exercise at 55% peak power output. Interleukin-6 was elevated above baseline immediately after the maximal but not the submaximal task. Compared with the control condition, IL-6 was increased at 30 and 60 min after both exercise tasks. The IL-6 response was greater in women than men at 60 min after maximal exercise. Cortisol increased in both tasks compared with the control condition, the increase being greater after maximal than submaximal exercise. No associations were found between IL-6 responses and cortisol, heart rate, fitness or body mass index. The results show that 45 min of moderate-intensity exercise can increase IL-6 and suggest that the inclusion of maximal effort may accelerate this response. The finding that women showed a greater IL-6 response to maximal exercise may reflect a gender dimorphism in the immune response to stress.  相似文献   

5.
The inflammatory responsive cytokine interleukin-6 (IL-6) helps regulate immune responses to exercise. Evidence suggests that increases in IL-6 are related to exercise duration and intensity. However, the moderating effect of sex and underlying mediators have received limited attention. We compared plasma IL-6 responses to two cycling tasks with a resting control in young male (n = 12) and female (n = 12) recreationally active adults. Both 45 min tasks comprised an incremental test, either maximal or submaximal, followed by steady-state exercise at 55% peak power output. Interleukin-6 was elevated above baseline immediately after the maximal but not the submaximal task. Compared with the control condition, IL-6 was increased at 30 and 60 min after both exercise tasks. The IL-6 response was greater in women than men at 60 min after maximal exercise. Cortisol increased in both tasks compared with the control condition, the increase being greater after maximal than submaximal exercise. No associations were found between IL-6 responses and cortisol, heart rate, fitness or body mass index. The results show that 45 min of moderate-intensity exercise can increase IL-6 and suggest that the inclusion of maximal effort may accelerate this response. The finding that women showed a greater IL-6 response to maximal exercise may reflect a gender dimorphism in the immune response to stress.  相似文献   

6.
Abstract

T'ai Chi Chuan (TCC) is a widely practiced Chinese martial art said to physically develop balance and coordination as well as enhance emotional and mental health. TCC consists of a series of postures combined into a sequential movement providing a smooth, continuous, low-intensity activity. The purpose of this study was to examine the ventilatory and cardiovascular responses to the Long Form of Yang's style TCC. In addition, the subjects' TCC responses were compared to their ventilatory and cardiovascular responses during cycle ergometry at an oxygen consumption (VO2) equivalent to the mean TCC VO2 Six experienced (M = 8.3 yrs) male TCC practitioners served as subjects with data collected during the Cloud Hand movement of the TCC exercise. Significantly (p < .05) lower responses for ventilatory frequency (Vf) (11.3 and 15.7 breaths min?1), ventilatory equivalent (VE!VO2) (23.47 and 27.41), and the ratio of dead space ventilation to tidal volume (VD!VT) (20 and 27%) were found in TCC in comparison to cycle ergometry. The percentage of minute ventilation used for alveolar ventilation was significantly higher during TCC (p < .03) than cycle ergometry, with mean values of 81.1% and 73.1%, respectively. Cardiac output, stroke volume, and heart rate were not significantly different between TCC exercise and cycle ergometry at the same oxygen consumption. We concluded that, during TCC, expert practitioners show significantly different ventilatory responses leading to more efficient use of the ventilatory volume than would be expected from comparable levels of exertion on a cycle ergometer.  相似文献   

7.
The effect of time of day on ratings of perceived exertion (RPE) at various intensities of cycling exercise, both below and above the ventilatory threshold, was studied in 32 subjects, 18 to 35 years of age. The ventilatory threshold occurred at the same (p greater than .05) mean (+/- SD) work rate in the morning (110.6 +/- 27.0 watts) and in the afternoon (111.9 +/- 23.9 watts) and was perceived as equally strenuous (p greater than .05) in the morning (RPE = 13.8 +/- 2.4) and in the afternoon (RPE = 13.6 +/- 2.8). At intensities below the ventilatory threshold, RPE was the same (p greater than .05) in the morning and in the afternoon; above the ventilatory threshold, RPE was lower (p less than .05) in the morning. We conclude that, during incremental submaximal cycling exercise above the ventilatory threshold, a particular work rate is perceived as less strenuous in the morning than in the afternoon. About 20% of this difference in RPE is explained by lower ventilatory demands in the morning.  相似文献   

8.
探讨优秀女子蹼泳队员心肺机能适应性变化和能量代谢特征,为培养蹼泳竞技人才提供训练效果评定的理论依据。通过对我国优秀女子蹼泳队员与一般女子蹼泳队员在递增负荷运动过程中气体代谢变化特征进行比较研究发现,运动开始时实验组肺通气机能动员速度快于对照组;中等强度时,实验组摄氧量（VO2）增加速度减缓;高等强度时,对照组呼吸频率（RR）、心率（HR）、氧通气当量（VEO2）和通气量（VE）迅速增加;力竭时实验组RR、氧脉搏（O2P）、VE和VO2均高于对照组。  相似文献   

9.
Abstract

This study was designed to compare man's normal working physiological performance to that during rapid dehydration and rehydration. Seven trained men participated in submaximal exercise trials at three conditions (normal, dehydrated, and rehydrated). During each test measurements were recorded on the subject's rectal temperature change during exercise and recovery, exercise and recovery minute heart rates, minute volume, oxygen consumption, respiratory quotient, ventilatory efficiency, and oxygen pulse. Analysis of the data, employing analysis of variance and Duncan's Multiple Range Test, indicated significant differences in mean exercise and second minute recovery heart rates, with an elevation during the dehydration test, and a return to normalcy for the rehydration test. Oxygen pulse decreased notably with dehydration, returning to normal with rehydration. Mean rectal temperature change, first minute recovery heart rate, oxygen consumption, ventilatory efficiency, minute volume, and respiratory quotient did not exhibit significant change.  相似文献   

10.
Abstract

The aim of the study was to compare physiological responses between runners adapted and not adapted to deep water running at maximal intensity and the intensity equivalent to the ventilatory threshold. Seventeen runners, either adapted (n = 10) or not adapted (n = 7) to deep water running, participated in the study. Participants in both groups undertook a maximal treadmill running and deep water running graded exercise test in which cardiorespiratory variables were measured. Interactions between adaptation (adapted vs. non-adapted) and condition (treadmill running vs. deep water running) were analysed. The main effects of adaptation and condition were also analysed in isolation. Runners adapted to deep water running experienced less of a reduction in maximum oxygen consumption ([Vdot]O2max) in deep water running compared with treadmill running than runners not adapted to deep water running. Maximal oxygen consumption, maximal heart rate, maximal ventilation, [Vdot]O2 at the ventilatory threshold, heart rate at the ventilatory threshold, and ventilation at the ventilatory threshold were significantly higher during treadmill than deep water running. Therefore, we conclude that adaptation to deep water running reduces the difference in [Vdot]O2max between the two modalities, possibly due to an increase in muscle recruitment. The results of this study support previous findings of a lower maximal and submaximal physiological response on deep water running for most of the measured parameters.  相似文献   

11.
测定了少年男子武术套路运动员组(12人)和普通对照组(5人)在连续递增负荷的蹬车运动中血氨、血乳酸、VE／VO2指标的变化曲线。结果显示，两组人员在运动过程中血氨、血乳酸、VE／VO2指标随运动强度的增加有规律上升，运动初期上升速度缓慢，当运动负荷增加到100W以上，三种指标上升速度加剧。结果提示，少年男子武术套路运动员比对照组有较好的心肺机能，血氨、血乳酸、VE／VO2指标与运动强度有高度相关性，三种指标联合使用可以更精确地评定运动强度、机体的机能状态及训练程度，指导少年武术套路运动员的运动训练。  相似文献   

12.
Above the lactate/ventilatory threshold, prolonged steady-state exercise produces a secondary rise in oxygen uptake, the slow oxygen component. The slow oxygen component 'represents an additional energetic requirement' above steady state; however, a lack of consensus on how to measure anaerobic energy expenditure makes it difficult to ascertain how or if anaerobic metabolism also contributes to energy expenditure. The aim of this study was to establish if the slow oxygen component is the sole source of 'additional energetic requirements' during steady-state exercise above the lactate/ventilatory threshold. Ten participants completed an 8 min continuous treadmill run and four 2 min intermittent runs at a speed of 2.67 m x s(-1) and a grade located halfway between the ventilatory threshold and maximum oxygen uptake. Each participant performed five submaximal runs below the ventilatory threshold to estimate energy expenditure at this exercise intensity. Both the oxygen deficit and the slow oxygen component were derived from this estimated energy expenditure. Oxygen equivalent units (ml O2) were used for comparison. The slow oxygen component for the 8 min continuous run began 2-4 min into exercise (73 ml O2), rose quickly at 4 6 min (178 ml O2) and declined at 6-8 min (96 ml O2). For the intermittent 2 min runs, a decrease in the oxygen deficit was seen between the first and second trial (-273 ml O2), indicating a larger aerobic energy expenditure contribution. The oxygen deficit began to increase when the third and fourth trials (+62 ml O2) were compared, suggesting a larger contribution to anaerobic energy expenditure. At the end of exercise, the intermittent oxygen deficit and continuous slow oxygen component revealed inverse associations; that is, in participants with large slow oxygen component contributions, the oxygen deficit was minimal; participants who had an increased oxygen deficit had smaller slow oxygen component contributions. The results suggest larger aerobic contributions to 'additional energetic requirements' when the slow oxygen component itself is large; however, smaller slow oxygen components do not necessarily indicate a lower energy expenditure. Individuals with smaller slow oxygen components during continuous exercise have larger oxygen deficits during intermittent exercise; thus an anaerobic contribution to the 'additional energetic requirement' may exist.  相似文献   

13.
Kinetics of heart rate responses to exercise   总被引：4，自引：0，他引：4  
In order to describe the kinetics of the reaction of the heart rate (HR) to the onset of exercise of constant intensity, the half-time (t1/2) of HR can be used. First in a study of exercise of intensity corresponding to 2 W kg-1 on a cycle ergometer, the t1/2 in 15 trained male rowers and 11 untrained male students was determined. In the trained subjects t1/2 was smaller than in untrained students, mean (+/- S.D.) values being 24.10 (+/- 3.36) s and 47.12 (+/- 4.08) s respectively. In both groups t1/2 was positively correlated with resting HR, r = 0.774 and 0.846 and negatively correlated with maximal oxygen uptake (VO2max), r = -0.728 and -0.871 respectively (P less than 0.01). The regulation of HR in the transition range was concluded to be very similar to the regulation of VO2 and energy requirements. The second part of this work was concerned with responses to graded exercise. The linearity of the HR-exercise intensity relationship is maintained up to a submaximal exercise intensity beyond which the increase in exercise intensity exceeds the increase in HR. It was hypothesized that the point where HR departs from linearity in an incremental exercise test may be employed as a predictor of the ventilatory threshold (Tvent). To examine this, 28 trained male long-distance runners were tested on a treadmill and 17 untrained young male subjects were tested on a cycle ergometer using a continuous incremental protocol. The Tvent was determined from the dependence of VE on VO2 and/or VCO2. The VO2, HR and exercise intensity at Tvent were compared with the same parameters determined from the dependence of HR on exercise intensity. No significant differences were found between Tvent and HR break point levels. It was concluded from this second study that the HR break point level coincides with Tvent.  相似文献   

14.
目的:通过对体育学院大学生进行为期一周的间歇性低氧刺激,观察刺激前后递增负荷运动心率、通气量、摄氧量及定量负荷时血乳酸的变化,探讨间歇性低氧刺激对人体最大摄氧量及通气阈的影响。方法:本实验分两个阶段,每阶段做两次运动负荷。12名体育系男生在实验室常氧条件下在跑台上采用Bruce方法进行递增负荷运动至力竭。间隔3天后进行75%最大摄氧量的定量负荷运动,运动时间为9min,定量负荷后立即进行连续7天,每天1h的12%~10%O2的常压间歇性低氧刺激。低氧刺激完成后第二天再次进行上述两种运动方案。在极限递增负荷至力竭运动前后分别测定心率(HR)、递增负荷至力竭时间(t)、最大摄氧量(VO2max%)、血乳酸(Bla)及定量负荷时Bla等指标。结果:(1)低氧刺激后,递增负荷至力竭运动时HRmax增加(P0.01),VEmax上升(P0.01),呼吸商(R)增加(P0.05),t明显延长(P0.05),Bla明显增加(P0.05),定量负荷运动Bla显著降低(P0.05);(2)间歇性低氧刺激后通气阈时,HR、VE、VO2max%、HRmax%均显著性变化(P0.05),其中VE、VO2max%低氧刺激前后差异非常显著(P0.01)。结论:经过间歇性低氧刺激,受试者在进行递增负荷的力竭性运动时运动时间明显延长,心率在运动后增加,人体通气阈时相对应的心率百分数、最大摄氧量百分比、肺通气量均明显提高,这表明人体有氧耐力和极限负荷运动能力均得到增强。  相似文献   

15.
Electromyographic analysis of repeated bouts of eccentric exercise   总被引：1，自引：0，他引：1  
The repeated bout effect refers to the protective effect provided by a single bout of eccentric exercise against muscle damage from a similar subsequent bout. The aim of this study was to determine if the repeated bout was associated with an increase in motor unit activation relative to force production, an increased recruitment of slow-twitch motor units or increased motor unit synchronization. Surface electromyographic (EMG) signals were recorded from the hamstring muscles during two bouts of submaximal isokinetic (2.6 rad x s(-1)) eccentric (11 men, 9 women) or concentric (6 men, 4 women) contractions separated by 2 weeks. The EMG per unit torque and median frequency were analysed. The initial bout of eccentric exercise resulted in strength loss, pain and muscle tenderness, while the repeated eccentric bout resulted in a slight increase in strength, no pain and no muscle tenderness (bout x time effects, P < 0.05). Strength, pain and tenderness were unaffected by either bout of concentric exercise. The EMG per unit torque and median frequency were not different between the initial and repeated bouts of eccentric exercise. The EMG per unit torque and median frequency increased during both bouts of eccentric exercise (P < 0.01) but did not change during either concentric bout. In conclusion, there was no evidence that the repeated bout effect was due to a neural adaptation.  相似文献   

16.
The purpose of this study was to investigate the acute effect of cigarette smoking on cardiac autonomic function in young adult smokers during dynamic exercise. Fourteen healthy young smokers (21.4 ± 3.4 years) performed peak and submaximal exercise protocols under control and smoking conditions. Resting and submaximal beat-to-beat R-R series were recorded and spectrally decomposed using the fast Fourier transformation. Smoking resulted in a significant decrease in work time, VO(2peak) and peak O(2) pulse (P < 0.05). Heart rate increased at rest and during submaximal exercise after smoking (P < 0.05). The raw high frequency and low frequency power were significantly reduced by smoking, both at rest and during exercise (P < 0.05). The low to high frequency ratio was higher after smoking (P < 0.05). The normalised low frequency power was also significantly increased by smoking, but only at rest (P < 0.05). These data demonstrate that the tachycardic effect elicited by smoking is accompanied by acute changes in heart rate spectral components both at rest and during exercise. Therefore, the cardiac autonomic control is altered by smoking not only at rest, but also during exercise, resulting in reduced vagal modulation and increased sympathetic dominance.  相似文献   

17.
The aim of this study was to examine the facilitating effects of physical exercise on the reaction process. Eleven participants with specific expertise in decision-making sports performed a choice reaction time task during moderate sub-maximal exercise (90% of their ventilatory threshold power). Participants were tested at rest and while cycling. During exercise, the participants were faster, without being more variable. We suggest that the effect of exercise on cognitive performance was due to a major generalized improvement of the whole distribution of response time and, although the benefit effect was small, it was consistent throughout the entire range of reaction times.  相似文献   

18.
The study was designed to determine the effect of upright-posture (UP) versus semirecumbent (SR) cycling on commonly used measures of maximal and submaximal exercise capacity. Nine healthy, untrained men (M age = 27 years, SD = 4.8 years) underwent steady-state submaximal aerobic testing followed by a ramped test to determine maximal oxygen consumption (VO2max). Anaerobic peak and average power and total work were assessed with the Wingate test. All tests were performed in both SR and UP positions, in random order. Oxygen consumption (VO2) and ventilation (VE) at the maximum workrate were lower in the SR position (p < .05). At submaximal workrates (50 W and 100 W), VO2 and VE were equivalent in the UP and SR positions, despite differences in tidal volume and respiratory rate (p < .05). There was no difference in peak or average anaerobic power in the two positions. In summary, SR exercise was associated with a reduced VO2max and a significantly altered ventilatory response to aerobic exercise, with no change in anaerobic power output.  相似文献   

19.
Abstract

The aim of this study was to examine the facilitating effects of physical exercise on the reaction process. Eleven participants with specific expertise in decision-making sports performed a choice reaction time task during moderate sub-maximal exercise (90% of their ventilatory threshold power). Participants were tested at rest and while cycling. During exercise, the participants were faster, without being more variable. We suggest that the effect of exercise on cognitive performance was due to a major generalized improvement of the whole distribution of response time and, although the benefit effect was small, it was consistent throughout the entire range of reaction times.  相似文献   

20.
血氨测定在运动人体科学中的应用   总被引：2，自引：0，他引：2  
总结了近年来运动与血氨水平的相关研究。剧烈运动中，氨主要的来源是单磷酸腺苷的脱氨基，而在次最大强度运动中支链氨基酸的分解占重要地位。比较了血氨与血乳酸对运动的反应；总结了影响血氨水平的各种因素；综述了血氨测定在监测与指导运动训练、间接测定肌纤维成分及肌肉糖原水平中的应用。  相似文献   

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