Erythropoietin concentration and arterial haemoglobin saturation with supramaximal exercise.

The aim of this study was to determine if the hypoxaemic stimulus generated by intense exercise results in the physiological response of increased erythropoietin production. Twenty athletes exercised for 3 min at 109 +/- 2.8% (mean +/- s) maximal oxygen consumption. Estimated oxyhaemoglobin saturation was measured by reflective probe pulse oximetry (Nellcor N200) and was validated against arterial oxyhaemoglobin saturation by CO-oximetry in eight athletes. Serum erythropoietin concentrations-as measured using the INCSTAR Epo-Trac radioimmunoassay-increased significantly by 28 +/- 9% at 24 h post-exercise in 11 participants, who also had an arterial oxyhaemoglobin saturation < or = 91% (P < 0.05). Decreased ferritin levels and increased reticulocyte counts were observed at 96 h post-exercise. However, no significant changes in erythropoietin levels were observed in nine non-desaturating athletes and eight non-exercise controls. Good agreement was shown between arterial oxyhaemoglobin saturation and percent estimated oxyhaemoglobin saturation (limits of agreement = -3.9 to 3.7%). In conclusion, short supramaximal exercise can induce both hypoxaemia and increased erythropoietin levels in well-trained individuals. The decline of arterial hypoxaemia levels below 91% during exercise appears to be necessary for the exercise-induced elevation of serum erythropoietin levels. Furthermore, reflective probe pulse oximetry was found to be a valid predictor of percent arterial oxyhaemoglobin saturation during supramaximal exercise when percent estimated oxyhaemoglobin saturation > or = 86%.     

Oxygen deficit and slow oxygen component relationships between intermittent and continuous exercise

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.     

Effects of hyperoxia during recovery from 5×30-s bouts of maximal-intensity exercise

We test the hypothesis that breathing oxygen-enriched air (F(I)O(2) = 100%) maintains exercise performance and reduces fatigue during intervals of maximal-intensity cycling. Ten well-trained male cyclists (age 25 ± 3 years; peak oxygen uptake 64.8 ± 6.2 ml · kg(-1) · min(-1); mean ± s) were exposed to either hyperoxic or normoxic air during the 6-min intervals between five 30-s sessions of cycling at maximal intensity. The concentrations of lactate and hydrogen ions [H(+)], pH, base excess, oxygen partial pressure, and oxygen saturation in the blood were assessed before and after these sprints. The peak (P = 0.62) and mean power outputs (P = 0.83) with hyperoxic and normoxic air did not differ. The partial pressure of oxygen was 4.2-fold higher after inhaling hyperoxic air, whereas lactate concentration, pH, [H(+)], and base excess (P ≥ 0.17) were not influenced. Perceived exertion towards the end of the 6-min periods after the fourth and fifth sprints (P < 0.05) was lower with hyperoxia than normoxia (P < 0.05). These findings demonstrate that the peak and mean power outputs of athletes performing intervals of maximal-intensity cycling are not improved by inhalation of oxygen-enriched air during recovery.     

短期高强度训练对优秀篮球运动员有氧耐力的影响

为了调查短期高强度训练对篮球运动员有氧耐力的影响 ,对 2 0名 (男、女各 10名 )优秀篮球运动员 ,进行跑台渐增负荷运动直到力竭为止。同时测定气体代谢最大吸氧量 (VO2max)、通气量 (VE)、血乳酸(BLa)、心率 (HR)、血睾酮 (T)、皮质醇 (Cor)及血红蛋白 (Hb)。结果为 :1)短期高强度训练期后男、女两组无氧阈 (AT)值与训练前相比较均有显著性差异 (P <0 .0 5 ) ,但VO2max却未有显著性差异 ;2 )短期高强度训练期后男、女两组Hb值与训练前相比较均有显著性差异 (P <0 .0 5 ) ,而T、Cor在训练期前后却未有显著性差异。其结果表明 ,短期高强度训练并不能提高VO2max,而AT却明显提高。提示可采用AT值作为反映篮球运动员有氧耐力的指标。     

The physiology of deep-water running

Deep-water running is performed in the deep end of a swimming pool, normally with the aid of a flotation vest. The method is used for purposes of preventing injury and promoting recovery from strenuous exercise and as a form of supplementary training for cardiovascular fitness. Both stroke volume and cardiac output increase during water immersion: an increase in blood volume largely offsets the cardiac decelerating reflex at rest. At submaximal exercise intensities, blood lactate responses to exercise during deep-water running are elevated in comparison to treadmill running at a given oxygen uptake (VO2). While VO2, minute ventilation and heart rate are decreased under maximal exercise conditions in the water, deep-water running nevertheless can be justified as providing an adequate stimulus for cardiovascular training. Responses to training programmes have confirmed the efficacy of deep-water running, although positive responses are most evident when measured in a water-based test. Aerobic performance is maintained with deep-water running for up to 6 weeks in trained endurance athletes; sedentary individuals benefit more than athletes in improving maximal oxygen uptake. There is some limited evidence of improvement in anaerobic measures and in upper body strength in individuals engaging in deep-water running. A reduction in spinal loading constitutes a role for deep-water running in the prevention of injury, while an alleviation of muscle soreness confirms its value in recovery training. Further research into the applications of deep-water running to exercise therapy and athletes' training is recommended.     

Total Protein of Whole Saliva as a Biomarker of Anaerobic Threshold

Saliva provides a convenient and noninvasive matrix for assessing specific physiological parameters, including some biomarkers of exercise. We investigated whether the total protein concentration of whole saliva (TPWS) would reflect the anaerobic threshold during an incremental exercise test. After a warm-up period, 13 nonsmoking men performed a maximum incremental exercise on a cycle ergometer. Blood and stimulated saliva were collected during the test. The TPWS anaerobic threshold (PAT) was determined using the Dmax method. The PAT was correlated with the blood lactate anaerobic threshold (AT; r = .93, p < .05). No significant difference (p = .16) was observed between PAT and AT. Thus, TPWS provides a convenient and noninvasive matrix for determining the anaerobic threshold during incremental exercise tests.     

Antioxidant diet supplementation enhances aerobic performance in amateur sportsmen

The effects of antioxidant diet supplements on blood lactate concentration and on the aerobic and anaerobic thresholds and their adaptations to training were analysed. Fifteen amateur male athletes were randomly assigned to either a placebo group or an antioxidant-supplemented group (90 days supplementation with 500 mg x day(-1) of vitamin E and 30 mg x day(-1) of beta-carotene, and the last 15 days also with 1 g x day(-1) of vitamin C). Before and after the antioxidant supplements, the sportsmen performed a maximal exercise test on a cycle ergometer and maximal and submaximal physiological parameters were assessed together with blood lactate concentration. Maximal oxygen uptake (VO(2max)), maximal blood lactate concentration, and the maximal workload attained rose significantly in both groups after the 3 months of training. At the end of the study, maximal blood lactate concentration was lower in the group that took supplements than in the placebo group. The percentage of VO(2max) attained at the anaerobic threshold rose significantly in both groups after 3 months of training, although the final value in the supplemented group was higher than that in the placebo group. Antioxidant diet supplements induced lower increases in blood lactate concentration after a maximal exercise test and could improve the efficiency in which aerobic energy is obtained.     

应用Monark测试系统对优秀速滑运动员专项能力的测试研究

采用Wingate无氧试验法,用894E奋力蹬车10s、30s、60s以及在839E上用递增负荷的方法对国家速滑队运动员的无氧功、无氧阈功率、运动后3min、6min、9min血乳酸进行测定。结果表明,10s、30s、60s无氧功试验以及运动后血乳酸的测试能较好评价速滑运动员磷酸原供能系统和糖酵解供能系统的供能能力,同时也反映速滑运动员的无氧功和无氧能力;无氧阈功率能较好地反映速滑运动员的有氧代谢能力,可用于对训练效果的评定和对训练过程的监控;在评价速滑运动员的无氧功时,应优先考虑其无氧功的绝对值。     

试论无氧阈跑速作为耐力测试指标的必要性及可行性

800 m、1 000 m跑测试是在用一个以无氧代谢供能为主的运动项目评测人的有氧耐力,成绩不能客观反映机体的有氧耐力水平,不能引导学生科学锻炼,还会让受试者承受较大的心理负荷,不利于运动兴趣培养和终生体育生活方式的养成,且在800 m、1 000 m跑测试中频频发生意外。研究认为,可用无氧阈跑速做耐力评测指标,它能确切反映人的有氧耐力水平,引导人们科学锻炼,强度由低到中,安全、简单,可在跑步机或场地上完成。     

3周1550 m亚高原训练对优秀青年男子越野滑雪运动员生理机能和身体成分影响研究

目的:探究3周海拔1550 m亚高原训练对优秀青年男子越野滑雪运动员生理机能和身体成分的影响,并且提出针对性的备战训练建议。方法:国家越野滑雪集训队10名优秀青年男子越野滑雪运动员[年龄(18.7±1.5)岁,身高(78.5±5.8)cm,体质量(66.6±4.7)kg]在亚高原(海拔1550 m)进行3周训练,并在亚高原训练前后对运动员的生理机能和身体成分进行系列测试。使用重复方差分析对运动员数据进行自身比较。结果:运动员由平原初上亚高原时,乳酸阈测试血乳酸浓度显著提升(P<0.05),最大摄氧量和红细胞浓度显著降低(P<0.05)。经过3周训练后,运动员的乳酸阈测试血乳酸浓度和最大摄氧量显著下降(P<0.05),全身总质量、上肢肌肉质量和下肢脂肪质量显著提升(P<0.05)。结论:由平原初上亚高原时,运动员乳酸阈能力和最大摄氧能力显著降低。3周亚高原训练后,运动员的乳酸阈能力和上肢肌肉水平显著提升,最大摄氧能力下降幅度明显。建议:在进行亚高原训练时,我国优秀青年越野滑雪运动员应当注重对心肺摄氧能力的训练,并且注意提升周平均高强度训练(high intensity training,HIT)训练总时间,以维持和提升最大摄氧能力。     

3周1550 m亚高原训练对优秀青年男子越野滑雪运动员生理机能和身体成分影响研究

目的:探究3周海拔1550 m亚高原训练对优秀青年男子越野滑雪运动员生理机能和身体成分的影响,并且提出针对性的备战训练建议。方法:国家越野滑雪集训队10名优秀青年男子越野滑雪运动员[年龄(18.7±1.5)岁,身高(78.5±5.8)cm,体质量(66.6±4.7)kg]在亚高原(海拔1550 m)进行3周训练,并在亚高原训练前后对运动员的生理机能和身体成分进行系列测试。使用重复方差分析对运动员数据进行自身比较。结果:运动员由平原初上亚高原时,乳酸阈测试血乳酸浓度显著提升(P<0.05),最大摄氧量和红细胞浓度显著降低(P<0.05)。经过3周训练后,运动员的乳酸阈测试血乳酸浓度和最大摄氧量显著下降(P<0.05),全身总质量、上肢肌肉质量和下肢脂肪质量显著提升(P<0.05)。结论:由平原初上亚高原时,运动员乳酸阈能力和最大摄氧能力显著降低。3周亚高原训练后,运动员的乳酸阈能力和上肢肌肉水平显著提升,最大摄氧能力下降幅度明显。建议:在进行亚高原训练时,我国优秀青年越野滑雪运动员应当注重对心肺摄氧能力的训练,并且注意提升周平均高强度训练(high intensity training,HIT)训练总时间,以维持和提升最大摄氧能力。     

Reliability of near-infrared spectroscopy for determining muscle oxygen saturation during exercise

Near-infrared spectroscopy is currently used to assess changes in the oxygen saturation of the muscle during exercise. The primary purpose of this study was to assess the reliability of near-infrared spectroscopy in determining muscle oxygen saturation (StO2) in the vastus lateralis during cycling and the gastrocnemius during running for exercise intensities at lactate threshold and maximal effort. Test-retest reliability was determined from an intraclass correlation coefficient obtained from a one-way analysis of variance. Reliability of muscle StO2 for the gastrocnemius at lactate threshold was R = .87, and R = .88 at maximal effort. Reliability of muscle StO2 for the vastus lateralis at lactate threshold was R = .94 and R = .99 at maximal effort.     

跑节省化、无氧阈和最大摄氧量评价篮球运动员有氧能力的比较研究

以天津商务职业学院24名男篮球队员为研究对象,通过跑台测试、因子分析法等,采用跑节省化、无氧阈和最大摄氧量对篮球运动员进行评价分析。结果显示:篮球运动员跑节省化的修正值在第一公因子中载荷最大,在第二、第三公因子中跑节省化相关指标的载荷量处于相对重要位置,在第四公因子中只有跑节省化时通气量;跑节省化、无氧阈和最大摄氧量三指标在评价篮球运动员有氧耐力时,跑节省化指标优势明显。提示:跑节省化可以作为评价篮球运动员有氧耐力的首选指标。     

Kinesthetic Perception of the Vertical as a Function of Sport Experience

Abstract

Near-infrared spectroscopy is currently used to assess changes in the oxygen saturation of the muscle during exercise. The primary purpose of this study was to assess the reliability of near-infrared spectroscopy in determining muscle oxygen saturation (StO₂) in the vastus lateralis during cycling and the gastrocnemius during running for exercise intensities at lactate threshold and maximal effort. Test-retest reliability was determined from an intraclass correlation coefficient obtained from a one-way analysis of variance. Reliability of muscle StO₂ for the gastrocnemius at lactate threshold was R = .87, and R= .88 at maximal effort. Reliability of muscle StO₂ for the vastus lateralis at lactate threshold was R= .94 and R = .99 at maximal effort.     

Physiological and metabolic responses of wheelchair athletes in different racing classes to prolonged exercise

The aims of this study were to examine and compare selected physiological and metabolic responses of wheelchair athletes in two paraplegic racing classes [T3: n = 8 (lesion levels T1-T7; paraplegics); T4: n = 9 (lesion levels below T7; paraplegics)] to prolonged exercise. In addition, we describe the responses of three tetraplegic athletes [T2: n = 3 (lesion levels C6/C7: tetraplegics)]. Twenty athletes completed 90 min of exercise at 75% VO2peak on a motorized treadmill adapted for wheelchairs. The mean (+/- s) heart rates of the T3 and T4 racing classes were 165 +/- 2 and 172 +/- 6 beats.min-1, respectively. For the T4 racing class, heart rate gradually increased during the test (P < 0.05), whereas for the T3 racing class, heart rate reached a plateau after an initial increase. The mean heart rate of the tetraplegics was 114 +/- 3 beats.min-1. The T3 and T4 classes exhibited similar respiratory exchange ratios, plasma lactate and glucose concentrations throughout the test. For both the T3 and T4 racing class, free fatty acid, glycerol, ammonia, urea and potassium concentrations had increased from resting values by the end of the test (P < 0.05). In conclusion, the results of this study suggest that endurance-trained wheelchair athletes are able to maintain velocities equivalent to the same relative exercise intensity (75% VO2peak) for prolonged periods irrespective of lesion level.     

Energy system contribution to 1500- and 3000-metre track running

The aim of the present study was to quantify the contributions of the aerobic and anaerobic energy systems to 1500- and 3000-m track running events during all-out time-trials performed individually on a synthetic athletic track. Ten 3000-m (8 males, 2 females) and fourteen 1500-m (10 males, 4 females) trained track athletes volunteered to participate in the study. The athletes performed a graded exercise test in the laboratory and two time-trials over 1500 or 3000?m. The contributions of the energy systems were calculated by measures of race oxygen uptake, accumulated oxygen deficit (AOD), race blood lactate concentration, estimated phosphocreatine degradation and some individual muscle metabolite data. The relative aerobic energy system contribution (based on AOD measures) for the 3000?m was 86% (male) and 94% (female), while for the 1500?m it was 77% (male) and 86% (female). Estimates of anaerobic energy expenditure based on blood lactate concentrations, while not significantly different (P?>?0.05), were generally lower compared with the AOD measures. In conclusion, the results of the present study conform with some recent laboratory-based measures of energy system contributions to these events.     

Energy system contribution to 1500- and 3000-metre track running

The aim of the present study was to quantify the contributions of the aerobic and anaerobic energy systems to 1500- and 3000-m track running events during all-out time-trials performed individually on a synthetic athletic track. Ten 3000-m (8 males, 2 females) and fourteen 1500-m (10 males, 4 females) trained track athletes volunteered to participate in the study. The athletes performed a graded exercise test in the laboratory and two time-trials over 1500 or 3000 m. The contributions of the energy systems were calculated by measures of race oxygen uptake, accumulated oxygen deficit (AOD), race blood lactate concentration, estimated phosphocreatine degradation and some individual muscle metabolite data. The relative aerobic energy system contribution (based on AOD measures) for the 3000 m was 86% (male) and 94% (female), while for the 1500 m it was 77% (male) and 86% (female). Estimates of anaerobic energy expenditure based on blood lactate concentrations, while not significantly different (P > 0.05), were generally lower compared with the AOD measures. In conclusion, the results of the present study conform with some recent laboratory-based measures of energy system contributions to these events.     

八段锦联合有氧踏车对PCI术后患者焦虑、抑郁及心肺功能的影响

目的:探讨八段锦训练联合有氧踏车训练对经皮冠状动脉治疗(percutaneous oronary interventio,PCI)术后患者的焦虑、抑郁情绪及心肺功能的影响。方法:选取首都医科大学附属北京康复医院心脏康复中心2018年2月-2020年1月收治的冠心病PCI后80例患者,随机分为实验组和对照组,对照组给予常规药物治疗及健康宣教,实验组在常规药物治疗及健康宣教基础上给予八段锦训练联合有氧踏车训练,一次训练包括30 min有氧踏车、28 min八段锦训练,3次/周(周一、三、五),持续12周。结果:术后第13周,实验组广泛性焦虑障碍(GAD-7)评分(3.23±1.72)及病例健康问卷(PHQ-9)评分(3.75±1.15)明显低于术后第1周GAD-7评分(4.68±2.86)及PHQ-9评分(4.93±2.76),具有显著性差异(P<0.001);与对照组比较,术后第13周实验组GAD-7评分与PHQ-9评分具有显著性差异(P<0.05);峰值摄氧量(19.84±1.12)ml·min^-1·kg^-1、峰值氧脉搏(12.91±0.72)ml.次^-1、无氧阈摄氧量(12.75±1.21)ml·min^-1·kg^-1、无氧阈代谢当量(4.68±0.56)METs,均明显高于术后第1周,具有显著性差异(P<0.001);实验组差值与对照组差值比较,具有显著性差异(P<0.001)。结论:八段锦训练联合有氧踏车训练能够明显改善患者的焦虑、抑郁情绪以及患者的心肺功能。     

Influence of pre-exercise glucose ingestion of two concentrations on paraplegic athletes

In this study, we assessed the influence that pre-exercise glucose ingestion of two concentrations has on the physiological responses of paraplegic athletes. Eight men with paraplegia ingested a drink containing 4% (low) or 11% (high) carbohydrate in a randomized double-blind crossover design, 20 min before exercise. The participants performed wheelchair exercise at 65% of peak oxygen uptake for 1 h followed by a 20 min performance test. During both trials, the physiological responses were similar and indicated steady-state exercise. At the onset of exercise, blood glucose concentrations in both trials increased after carbohydrate ingestion (P < 0.05) before returning to resting values after 20 min of exercise and there were no differences between trials. Free fatty acid concentrations increased from rest to 1 h of exercise in both trials, with a greater increase during the low carbohydrate trial that led to a difference in free fatty acids between trials at the end of the 1 h tests (P < 0.05). There was a tendency for the performance distances and power outputs achieved during the high carbohydrate trial to be greater than those achieved during the low carbohydrate trial (P= 0.08). In conclusion, when paraplegic athletes ingested low and high carbohydrate drinks before exercise, the decline in blood glucose concentrations was similar. The tendency for higher blood glucose concentrations, respiratory exchange ratios and power outputs and lower free fatty acid concentrations (P < 0.05) during the high carbohydrate trial suggests that a higher concentration of carbohydrate in a sports drink might be a better choice for paraplegic athletes.