血容量对运动训练及高原应激的调节适应

采用文献法，综述了血容量在运动训练及高原应激过程中的变化规律和对有氧能力的影响，希望能为在运用红细胞计数，血红蛋白浓度和红细胞压积等常规指标评价运动员身体机能状态和指导训练时，提供更科学全面的分析线索。     

Iron balance and iron supplementation for the female athlete: A practical approach

Maintaining a positive iron balance is essential for female athletes to avoid the effects of iron deficiency and anaemia and to maintain or improve performance. A major function of iron is in the production of the oxygen and carbon dioxide carrying molecule, haemoglobin, via erythropoiesis. Iron balance is under the control of a number of factors including the peptide hormone hepcidin, dietary iron intake and absorption, environmental stressors (e.g. altitude), exercise, menstrual blood loss and genetics. Menstruating females, particularly those with heavy menstrual bleeding are at an elevated risk of iron deficiency. Haemoglobin concentration [Hb] and serum ferritin (sFer) are traditionally used to identify iron deficiency, however, in isolation these may have limited value in athletes due to: (1) the effects of fluctuations in plasma volume in response to training or the environment on [Hb], (2) the influence of inflammation on sFer and (3) the absence of sport, gender and individually specific normative data. A more detailed and longitudinal examination of haematology, menstrual cycle pattern, biochemistry, exercise physiology, environmental factors and training load can offer a superior characterisation of iron status and help to direct appropriate interventions that will avoid iron deficiency or iron overload. Supplementation is often required in iron deficiency; however, nutritional strategies to increase iron intake, rest and descent from altitude can also be effective and will help to prevent future iron deficient episodes. In severe cases or where there is a time-critical need, such as major championships, iron injections may be appropriate.     

Hyperhydration using different hydration agents does not affect the haematological markers of the athlete biological passport in euhydrated volunteers

ABSTRACT

Athlete Biological Passport (ABP) is an indirect approach, implemented by WADA, aimed at detecting blood manipulation based on abnormal changes in haematological markers. Cases report the use of hyperhydration as masking method during anti-doping urine sample collection which could potentially mask suspicious fluctuations on ABP profiles. This study investigated the hyperhydration effect on haemoglobin concentration, reticulocyte percentage and OFF-hr score (an algorithm based on haemoglobin concentration and reticulocyte percentage), with and without recombinant human erythropoietin (rHuEPO) administration. A five-week clinical study performed; Baseline and rHuEPO Phase. Water and a sports drink were used as hyperhydration agents. To examine the hyperhydration effect on the normal ABP profile per volunteer, hyperhydration was implemented at 0, 24 and 48 hours during the baseline. During the rHuEPO phase, volunteers received Epoetin beta (3000 IU) with hyperhydration to be implemented at 0, 24 and 48 hours after drug administration. Blood and urine samples were collected and analysed according to WADA guidelines. No significant effect on ABP markers was observed due to hyperhydration at any time during the study. Pre- and post-hyperhydration data were not statistically different compared to individual baseline data. In conclusion, hyperhydration does not affect the ABP haematological markers under the examined conditions.     

Physiological effects of altitude training on elite male cross-country skiers.

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.     

The effects of skin and core tissue cooling on oxygenation of the vastus lateralis muscle during walking and running

Skin and core tissue cooling modulates skeletal muscle oxygenation at rest. Whether tissue cooling also influences the skeletal muscle deoxygenation response during exercise is unclear. We evaluated the effects of skin and core tissue cooling on skeletal muscle blood volume and deoxygenation during sustained walking and running. Eleven male participants walked or ran six times on a treadmill for 60 min in ambient temperatures of 22°C (Neutral), 0°C for skin cooling (Cold 1), and at 0°C following a core and skin cooling protocol (Cold 2). Difference between oxy/deoxygenated haemoglobin ([diffHb]: deoxygenation index) and total haemoglobin content ([tHb]: total blood volume) in the vastus lateralis (VL) muscle was measured continuously. During walking, lower [tHb] was observed at 1 min in Cold 1 and Cold 2 vs. Neutral (P?0.05). Lower [diffHb] was seen at 1 and 10 min in Cold 2 vs. Neutral by 13.5 ± 1.2 µM and 15.3 ± 1.4 µM and Cold 1 by 10.4 ± 3.1 µM and 11.1 ± 4.1 µM, respectively (P?0.05). During running, [tHb] was lower in Cold 2 vs. Neutral at 10 min only (P = 0.004). [diffHb] was lower at 1 min in Cold 2 by 11.3 ± 3.1 µM compared to Neutral and by 13.5 ± 2.8 µM compared to Cold 1 (P?0.001). Core tissue cooling, prior to exercise, induced greater deoxygenation of the VL muscle during the early stages of exercise, irrespective of changes in blood volume. Skin cooling alone, however, did not influence deoxygenation of the VL during exercise.     

Erythrocyte Changes during Training in High School Women Cross-Country Runners

Abstract

Indices of red blood cell (RBC) status were assessed in eight high school women cross-country runners (experimental group) six times during a competitive season (Weeks 0, 1, 2, 4, 6, and 8) and three times (Weeks 0, 1, and 3) in 11 high school women who were not runners (comparison group). The only significant preseason hematological difference between the groups was a higher RBC fragility for the runners. All blood indices for both groups were within normal ranges throughout the study. During the competitive season (Weeks 0–8), the runners had a significant increase in [Vdot]O₂ max (ml/kg · min^?1) of 7.6% and a significant decrease in post step-test heart rate (13.4%) but showed no changes in body weight, height, or percent body fat. At Week 3, the comparison group showed an increase (0.9%) in body weight, but no changes were observed in the other anthropometric variables or post step-test heart rate. During the competitive season, the runners had significant changes in all blood variables except reticulocyte count; these changes were most marked during the first week of the season when there were significant decreases in hemoglobin (Hb) concentration (8.0%), hematocrit (Hct) (7.7%), RBC count (6.8%), and osmotic fragility (21.5% and 42.0% in 5.95 and 6.80 mM NaCl solutions, respectively) and a significant increase in mean RBC volume (1.8%). In contrast, the only significant change in blood indices of the comparison group was a decrease (1.9%) in mean RBC volume at the end of Week 1. Changes in blood variables of the runners appeared to be transient, in that values at Week 8 were comparable to those at preseason except for mean RBC volume. Although blood volume changes could be responsible for some of the blood variable changes in the runners, the results support increased RBC destruction rather than hemodilution as a cause of the RBC changes in the runners, and suggest a possible stress on body iron reserves for increased erythropoiesis during recovery from those changes.     

The oxygen-conserving potential of the diving response: A kinetic-based analysis

We investigated the oxygen-conserving potential of the human diving response by comparing trained breath-hold divers (BHDs) to non-divers (NDs) during simulated dynamic breath-holding (BH). Changes in haemodynamics [heart rate (HR), stroke volume (SV), cardiac output (CO)] and peripheral muscle oxygenation [oxyhaemoglobin ([HbO₂]), deoxyhaemoglobin ([HHb]), total haemoglobin ([tHb]), tissue saturation index (TSI)] and peripheral oxygen saturation (SpO₂) were continuously recorded during simulated dynamic BH. BHDs showed a breaking point in HR kinetics at mid-BH immediately preceding a more pronounced drop in HR (?0.86 bpm.%^?1) while HR kinetics in NDs steadily decreased throughout BH (?0.47 bpm.%^?1). By contrast, SV remained unchanged during BH in both groups (all P > 0.05). Near-infrared spectroscopy (NIRS) results (mean ± SD) expressed as percentage changes from the initial values showed a lower [HHb] increase for BHDs than for NDs at the cessation of BH (+24.0 ± 10.1 vs. +39.2 ± 9.6%, respectively; P < 0.05). As a result, BHDs showed a [tHb] drop that NDs did not at the end of BH (?7.3 ± 3.2 vs. ?3.0 ± 4.7%, respectively; P < 0.05). The most striking finding of the present study was that BHDs presented an increase in oxygen-conserving efficiency due to substantial shifts in both cardiac and peripheral haemodynamics during simulated BH. In addition, the kinetic-based approach we used provides further credence to the concept of an “oxygen-conserving breaking point” in the human diving response.     

Near-infrared spectroscopy-derived total haemoglobin as an indicator of changes in muscle blood flow during exercise-induced hyperaemia

ABSTRACT

Blood flow changes in response to exercise have been attributed, among other factors, to the effect of vasodilators factors on the microvasculature, suggesting a close relationship between small blood vessels and conducting arteries. The main purpose of this study was to determine the relationship between the changes in near infrared spectroscopy (NIRS)-derived total haemoglobin ([tHb]) and muscle oxygen saturation (SmO₂) signals and femoral artery blood flow in response to resistance exercise at fast- and slow-velocity muscle contraction. The study randomised crossover design included twelve participants. NIRS and blood flow measurements were continuously monitored before, during, and 5 min after the exercise protocol. There was a significant correlation between [tHb] reperfusion slope ([tHb]_slope) and peak blood flow (BF_peak) after slow- and fast-velocity muscle contraction (r = 0.83, p = 0.0008 and r = 0.72, p = 0.0080, respectively). No significant correlation existed between the SmO₂ reperfusion slope (SmO_{2_slope}) and BF_peak after both slow- and fast-velocity muscle contraction exercise (r = ?0.46, p = 0.1253 and r = 0.33, p = 0.2841, respectively). This study demonstrated a strong relationship between the NIRS-derived [tHb] and Doppler ultrasound BF during the recovery period of dynamic resistance exercise at both slow- and fast-velocity contraction.     

A Physiological Comparison of Performance-Matched Female and Male Distance Runners

Abstract

Eight male and eight female runners were matched on performance in a 24.2 km (15 mile) road race (X time ± SD = 115.1 ± 2.2 min for females, 115.8 ± 3.2 min for males). All subjects completed a graded treadmill run during which [Vdot]O ₂ and heart rate (HR) were monitored at several submaximal running speeds and at maximal exercise. Blood samples, collected at rest and 3 min after maximal exercise, were analyzed for hematocrit and hemoglobin (Hb), lactic acid (LA) and 2,3-diphosphoglyceric acid (2,3-DPG) concentrations. Body composition was assessed via hydrostatic weighing. Group comparisons revealed that the males were taller, heavier, and higher in Hb than the females (p < .05). The sexes did not differ significantly in percentage of body fat or in [Vdot]O ₂ (ml · kg ^–1 · min ^–1 ), HR, respiratory exchange ratio, or ventilatory equivalent of oxygen during submaximal running or at maximal exercise (p > .05). 2,3-DPG was higher in the females when expressed relative to Hb (p < .05). These data indicate that female and male distance runners of equal performance levels are very similar in body composition and in metabolic and cardiorespiratory responses to exercise. The higher Hb observed in males may have been offset in part by the females' higher 2,3-DPG/Hb ratio.     

No effect of glutamine supplementation and hyperoxia on oxidative metabolism and performance during high-intensity exercise

Abstract

Glutamine enhances the exercise-induced expansion of the tricarboxylic acid intermediate pool. The aim of the present study was to determine whether oral glutamine, alone or in combination with hyperoxia, influenced oxidative metabolism and cycle time-trial performance. Eight participants consumed either placebo or 0.125 g · kg body mass^?1 of glutamine in 5 ml · kg body mass^?1 placebo 1 h before exercise in normoxic (control and glutamine respectively) or hyperoxic (FiO₂ = 50%; hyperoxia and hyperoxia + glutamine respectively) conditions. Participants then cycled for 6 min at 70% maximal oxygen uptake ([Vdot]O_2max) immediately before completing a brief high-intensity time-trial (～4 min) during which a pre-determined volume of work was completed as fast as possible. The increment in pulmonary oxygen uptake during the performance test (Δ[Vdot]O_2max, P = 0.02) and exercise performance (control: 243 s, s _x  = 7; glutamine: 242 s, s _x  = 3; hyperoxia: 231 s, s _x  = 3; hyperoxia + glutamine: 228 s, s _x  = 5; P < 0.01) were significantly improved in hyperoxic conditions. There was some evidence that glutamine ingestion increased Δ[Vdot]O_2max in normoxia, but not hyperoxia (interaction drink/FiO₂, P = 0.04), but there was no main effect or impact on performance. Overall, the data show no effect of glutamine ingestion either alone or in combination with hyperoxia, and thus no limiting effect of the tricarboxylic acid intermediate pool size, on oxidative metabolism and performance during maximal exercise.     

干血点技术在反兴奋剂领域的应用研究与前景展望

作为一种血液样本的替代采集方法,干血点(dried blood spot,DBS)采样技术在新生儿筛查以及临床和药学等领域被广泛应用,同时在反兴奋剂领域也受到了关注。为进一步了解DBS在运动员样本的采集、运输、保存等方面的潜在优势以及在兴奋剂检测中的研究现状,对近10年的相关文献资料进行归纳总结,发现DBS技术具有操作简单、血量需求少、微创性、易保存与运输等优势,克服了传统采样方法的诸多缺点;同时,DBS与液相色谱和质谱技术联用在各类禁用物质检测中也显示出一定优势,DBS是一种良好的替代或补充基质。就DBS在当前应用中面临的难点以及可能的解决方法进行探讨,并对DBS在反兴奋剂领域的应用前景进行展望。     

Precision of the optimized carbon monoxide rebreathing method to determine total haemoglobin mass and blood volume

Abstract

The aim of this study was to evaluate the influence of different apparatuses, procedures and calculations on the precision of the optimized carbon monoxide method. Total haemoglobin mass was determined twice on consecutive days in 11 subjects using both venous and capillary blood samples. To estimate loss of carbon monoxide due to exhalation, carbon monoxide concentration was measured by two portable carbon monoxide analysers (Fluke CO-220, Fluke, Norwich, UK and Pac 7000 Carbon Monoxide, Draeger Safety, Northumberland, UK) and alveolar ventilation was specified using an automated metabolic gas analysis system (Cosmed Quark b2, Cosmed, Rome, Italy). Blood volume was derived from total haemoglobin mass using haemoglobin concentration and haematocrit obtained in both the supine and the seated position. Two different formulae to calculate blood volume were also compared. Precision was good for both total haemoglobin mass and blood volume measurements performed on consecutive days (typical error < 2%). Using Fluke CO-220 analyser, an estimated alveolar ventilation and capillary blood, total haemoglobin mass (917±136 g) was similar when compared to the Pac 7000 Draeger CO-analyser (904±137 g; mean bias –13 g with 95% limits of agreement –26 to + 1 g, P=0.76), specified alveolar ventilation (911±132 g, mean bias –6 g with 95% limits of agreement –18 g to + 6 g, P =0.87) and venous blood (917±134 g, mean bias 0 g with 95% limits of agreement –38 to + 38 g, P=0.99), respectively. Blood volume determination was also not significantly affected by the supine vs. seated position (6.7±0.8 l vs. 6.6±0.8 l, P=0.56) but can deviate by ~0.6 l (P=0.01) depending on the formula applied. Thus, the good precision of the assessment of total haemoglobin mass and blood volume using the optimized carbon monoxide rebreathing method is not significantly influenced by the make of CO analyser, method of obtaining alveolar ventilation, blood sampling method and subject position, but should for longitudinal monitoring purposes use the same formula.     

Human genetic variation: new challenges and opportunities for doping control

Sport celebrates differences in competitors that lead to the often razor-thin margins between victory and defeat. The source of this variation is the interaction between the environment in which the athletes develop and compete and their genetic make-up. However, a darker side of sports may also be genetically influenced: some anti-doping tests are affected by the athlete's genotype. Genetic variation is an issue that anti-doping authorities must address as more is learned about the interaction between genotype and the responses to prohibited practices. To differentiate between naturally occurring deviations in indirect blood and urine markers from those potentially caused by doping, the "biological-passport" program uses intra-individual variability rather than population values to establish an athlete's expected physiological range. The next step in "personalized" doping control may be the inclusion of genetic data, both for the purposes of documenting an athlete's responses to doping agents and doping-control assays as well facilitating athlete and sample identification. Such applications could benefit "clean" athletes but will come at the expense of risks to privacy. This article reviews the instances where genetics has intersected with doping control, and briefly discusses the potential role, and ethical implications, of genotyping in the struggle to eliminate illicit ergogenic practices.     

《反兴奋剂教育国际标准》解读——以“孙杨案”为起点

“孙杨案”暴露了运动员与其辅助人员，以及体育组织在反兴奋剂教育方面存在的问题。解决该问题的起点是制定反兴奋剂教育的国际规则。《反兴奋剂教育国际标准》作为反兴奋剂国际规则体系中全新的单行规范性文件，具有里程碑式的意义，它明确了反兴奋剂教育的首要基本原则，规定了签约方在制定、实施和评估教育方案时的标准、义务和责任，增强了反兴奋剂教育的可行性，但仍存在不足。由此，建议未来要统一教育与反兴奋剂教育的定义，不再在分论部分重复表述首要基本原则，删减第三部分中签约方一般义务的表述，专条规定国际(残)奥委会的角色和责任。同时，应当参照国际标准完善我国的反兴奋剂教育规则，尽量采用《反兴奋剂教育指南》的建议，建立反兴奋剂教育咨询专家库，推动反兴奋剂教育预防体系的构建。     

短跑运动员不同强度时唾液溶菌酶的变化特点

笔者对 10名短跑运动员进行了为期 7天的不同强度负荷短跑训练 ,采用琼脂平皿扩散法测定了受试者唾液溶菌酶滴定值 ,并同步测定了血尿素和尿白蛋白作对照。结果表明 :唾液溶菌酶对中低强度运动负荷反应灵敏 ,所反映的机能状态与血尿素、尿AIb所反映的相似。提示 :唾液溶菌酶有可能作为运动员训练中运动量评定的无创性指标 ,但在大强度负荷条件下运动员唾液溶菌酶个体差异大 ,运用该指标进行运动量评定时 ,需区别对待。     

Effect of acute ingestion of β-hydroxybutyrate salts on the response to graded exercise in trained cyclists

Acute ingestion of ketone salts induces nutritional ketosis by elevating β-hydroxybutyrate (βHB), but few studies have examined the metabolic effects of ingestion prior to exercise. Nineteen trained cyclists (12 male, 7 female) undertook graded exercise (8 min each at ～30%, 40%, 50%, 60%, 70%, and 80% VO_2peak) on a cycle ergometer on two occasions separated by either 7 or 14 days. Trials included ingestion of boluses of either (i) plain water (3.8?mL?kg?body mass^?1) (CON) or (ii) βHB salts (0.38?g?kg?body mass^?1) in plain water (3.8?mL?kg body mass^?1) (KET), at both 60 min and 15 min prior to exercise. During KET, plasma [βHB] increased to 0.33?±?0.16?mM prior to exercise and 0.44?±?0.15?mM at the end of exercise (both p?.05). Plasma glucose was 0.44?±?0.27?mM lower (p?.01) 30?min after ingestion of KET and remained ～0.2?mM lower throughout exercise compared to CON (p?.001). Respiratory exchange ratio (RER) was higher during KET compared to CON (p?.001) and 0.03–0.04 higher from 30%VO_2peak to 60%VO_2peak (all p?.05). No differences in plasma lactate, rate of perceived exertion, or gross or delta efficiency were observed between trials. Gastrointestinal symptoms were reported in 13 out of 19 participants during KET. Acute ingestion of βHB salts induces nutritional ketosis and alters the metabolic response to exercise in trained cyclists. Elevated RER during KET may be indicative of increased ketone body oxidation during exercise, but at the plasma βHB concentrations achieved, ingestion of βHB salts does not affect lactate appearance, perceived exertion, or muscular efficiency.     

体育法治全球化的典型例证与法理分析

以体育法治全球化何以可能着手,对反兴奋剂法治的全球化和国际体育仲裁实践两个体育法治全球化的典型例证进行考察,并针对两者进行法理分析。研究认为世界反兴奋剂法治和国际体育仲裁实践直接推动了体育法治全球化的发展;体育法治全球化将催生全球体育法治体系,这一体系已经演变成一种新的全球法律治理模式,并将为其它领域的国际法律和司法制度发展提供重要的范例。     

低氧训练对我国运动员血红蛋白水平影响的Meta分析

运用Meta分析方法综合定量评估不同低氧训练模式对我国运动员血红蛋白（Hb）水平的影响,为科学运用低氧训练提供参考意见。方法：对中国知网、万方、维普、Web of Science、Pubmed数据库中的文献进行检索,对所纳入文献的相关指标进行分析。结果：（1）低氧训练有助于提升运动员Hb浓度,总体影响程度属于中等效应水平,Hb浓度平均升高5.57 g/L;(2)高住低练（HiLo）模式对运动员Hb浓度的影响程度处于较高效应水平,Hb浓度平均升高6.78 g/L,高住高练低训（HiHiLo）模式次之,最后为高住高练（HiHi）模式;（3）不同HiLo训练持续时间对Hb水平影响不同,当训练持续时间为4周时,对Hb浓度增长幅度最明显;当训练持续时间小于4周时,Hb浓度水平则呈下降趋势。结论：总体而言,低氧训练对提升Hb水平有明显效果,但持续4周的HiLo模式对提高运动员Hb水平最优。     

从社会文化视角对国际反兴奋剂行动的再认识

通过文献研究,从社会文化视角反思国际反兴奋剂行动的历史,并分析不同国家民族文化、不同运动项目下兴奋剂与反兴奋剂问题的实践与特征,然后,对国际反兴奋剂行动进行批判分析。认为与兴奋剂、反兴奋剂有关的思想与行为因各国文化的不同而各不相同,并随着时间的推移而改变,不同项目也存在些许差异;个体、社会、制度以及更广泛的文化框架,赋予了兴奋剂与反兴奋剂问题特殊的含义;反兴奋剂本身也存在着权利运动、道德恐慌夸大和不可预知的后果。     

Pulmonary Function at Rest and during Exercise in Uncomplicated Obesity

Abstract

Nine lean (6.9%–19.3% body fat) and 12 moderately obese (31.6%–42.3% body fat) college men were compared in terms of maximum aerobic power, resting pulmonary function tests, and selected respiratory variables during a progressive bicycle ergometer test. The [Vdot]O₂ max (1/min) was slightly higher (p > .05) in the obese group but significantly lower (p < .05) when expressed in cc/kg min or cc/kg FFBW min. Lower RV, ERV, and FRC data were observed in the obese group, but no differences were documented for tests of FVC or MVV. Higher values were displayed by the obese subjects for [Vdot]E, [Vdot]A, and tidal volume at rest and during each submaximal intensity of bicycle work. These observations appeared to be due to the obese subjects' higher energy expenditures, since no differences were documented in the ventilation equivalent ([Vdot]E/[Vdot]O₂), the [Vdot]A/[Vdot]E ratio, or breathing frequency. It was concluded, within the limitations of the study, that the hypothesis of respiratory dysfunction in the moderately obese was not supported.