Return to play after acute infectious disease in football players

Abstract

Acute infectious diseases are common in athletes and can impair their ability to train and to compete. Furthermore, continuing exercise during infectious diseases may lead to prolongation or aggravation of illness with severe acute or chronic organ manifestations. Therefore, even simple infectious diseases require a sufficient period of convalescence and recovery, during which exercise may be not allowed. Nowadays, especially in professional football with high pressures on players, staff and clubs due to broad public interests as well as financial constraints, the return-to-play decision is of utmost significance. Based on previous suggestions and our own experience within amateur and professional athletes and football players, this article aims to give a short overview on return-to-play decisions after common acute infectious diseases in football players.     

Ventilatory acclimatisation is beneficial for high-intensity exercise at altitude in elite cyclists

Aim: The aim of this study was to examine the relationship between ventilatory adaptation and performance during altitude training at 2700?m. Methods: Seven elite cyclists (age: 21.2?±?1.1?yr, body mass: 69.9?±?5.6?kg, height 176.3?±?4.9?cm) participated in this study. A hypoxic ventilatory response (HVR) test and a submaximal exercise test were performed at sea level prior to the training camp and again after 15 d at altitude (ALT15). Ventilation (V_E), end-tidal carbon-dioxide partial pressure (P_ETCO₂) and oxyhaemoglobin saturation via pulse oximetry (SpO₂) were measured at rest and during submaximal cycling at 250?W. A hill climb (HC) performance test was conducted at sea level and after 14 d at altitude (ALT14) using a road of similar length (5.5–6?km) and gradient (4.8–5.3%). Power output was measured using SRM cranks. Average HC power at ALT14 was normalised to sea level power (HC%). Multiple regression was used to identify significant predictors of performance at altitude. Results: At ALT15, there was a significant increase in resting V_E (10.3?±?1.9 vs. 12.2?±?2.4?L·min^?1) and HVR (0.34?±?0.24 vs. 0.71?±?0.49?L·min^?1·%^?1), while P_ETCO₂ (38.4?±?2.3 vs. 32.1?±?3.3?mmHg) and SpO₂ (97.9?±?0.7 vs. 94.0?±?1.7%) were reduced (P?V_E at altitude as significant predictors of HC% (adjusted r²?=?0.913; P?=?0.003). Conclusions: Ventilatory acclimatisation occurred during a 2 wk altitude training camp in elite cyclists and a higher HVR was associated with better performance at altitude, relative to sea level. These results suggest that ventilatory acclimatisation is beneficial for cycling performance at altitude.     

Hepatitis during respiratory syncytial virus infection – a case report

Introduction:

Respiratory syncytial virus (RSV) infection is the most common cause of hospitalization in infants and small children. The aim was to present a 13-months old boy diagnosed with acute airway infection, acute otitis media (AOM) and hepatitis during the RSV-infection.

Material and methods:

Serum catalytic activities of alkaline phosphatase (ALP), aspartate aminotranspherase (AST), alanine aminotranspherase (ALT), gamma glutamyl transpherase (GGT), lactate dehydrogenase (LD), and concentrations of bilirubin were monitored during hospitalization and at control examination.

Results:

The child had clinical signs and symptoms of respiratory failure, AOM, and laboratory findings of virus infection and liver disease. On admission, catalytic activities of enzymes were markedly increased, especially the activity of ALP (10333 U/L, i.e. 24-fold increase in comparison with the upper reference limit). The highest increased in AST (339 U/L, 4.5-fold), ALT (475 U/L, 10.3-fold) and LD (545 U/L, 1.5-fold) were registered on the 3^rd day, and the highest increase in GGT (68 U/L, 3.1-fold) occurred on the 11th day. Seven weeks after discharge AST, ALT, GGT and LD decreased into reference range, and ALP remain mildly increased (478 U/L, 1.1 fold increase). RSV was confirmed in nasal lavage fluid.

Conclusion:

Laboratory results in patient with RSV infection needs to be interpreted in the light of both, respiratory and extrapulmonary manifestations of the infection, respectively.     

Exhaled breath condensate – from an analytical point of view

Over the past three decades, the goal of many researchers is analysis of exhaled breath condensate (EBC) as noninvasively obtained sample. A total quality in laboratory diagnostic processes in EBC analysis was investigated: pre-analytical (formation, collection, storage of EBC), analytical (sensitivity of applied methods, standardization) and post-analytical (interpretation of results) phases. EBC analysis is still used as a research tool. Limitations referred to pre-analytical, analytical, and post-analytical phases of EBC analysis are numerous, e.g. low concentrations of EBC constituents, single-analyte methods lack in sensitivity, and multi-analyte has not been fully explored, and reference values are not established. When all, pre-analytical, analytical and post-analytical requirements are met, EBC biomarkers as well as biomarker patterns can be selected and EBC analysis can hopefully be used in clinical practice, in both, the diagnosis and in the longitudinal follow-up of patients, resulting in better outcome of disease.     

Mannose-binding lectin 2 gene polymorphism and susceptibility to upper respiratory tract infection among endurance athletes

Abstract

The aim of this study was to investigate the influence of mannose-binding lectin 2 (MBL2)-exon-1 gene polymorphisms on upper respiratory tract infection (URTI) incidence among endurance athletes. To this end, 100 healthy elite male athletes participating in the study were classified as either healthy or prone to frequent URTI. Blood samples, DNA isolation, multiplex polymerase chain reaction (PCR) and conventional PCR-RFLP were performed. Genomic DNA was extracted from peripheral leukocytes of whole blood samples using the QIAmp DNA Blood Mini Kit. For comparison of the distribution of genotypes between two groups and for estimating odds ratios (OR) for URTI susceptibility in relation to the MBL2-exon-1 polymorphism, Pearson's chi-square and logistic regression method were used, respectively. The MBL2-exon-1 genotype distribution differed between athletes with URTI and healthy athletes (χ² = 7.81, p = 0.02). The AO and AO + OO genotypes of MBL2 were observed at a greater frequency in the illness-prone group compared with the healthy group (34.04% vs. 11.32%). In conclusion, findings from this study have identified a potential role of genetic variation in influencing the risk for URTI in athletic populations and single-nucleotide polymorphisms (SNPs) in the MBL2-exon-1 genes were associated with an altered risk profile. These measures may have a predictive value in the identification of individuals who are more likely to experience recurrent infections when exposed to high physical stress in the areas of athletic endeavour.     

The relationship between critical speed and the respiratory compensation point: Coincidence or equivalence

Abstract

It has previously been suggested that the respiratory compensation point (RCP) and critical speed (CS) parameters are equivalent and, therefore, like CS, RCP demarcates the boundary between the heavy- and severe-intensity domains. However, these findings are equivocal and therefore must be interpreted cautiously. Thus, we examined the relationship between CS and RCP across a wide range of subject fitness levels, in an attempt to determine if CS and RCP are equivalent. Forty men and 30 women (age: 23.2 ± 2.5 year, height: 174 ± 10 cm, body mass: 74.1 ± 15.7 kg) completed an incremental and four constant-speed protocols on a treadmill. RCP was determined as the point at which the minute ventilation increased disproportionately to CO₂ production and the end-tidal CO₂ partial pressure began to decrease. CS was determined from the constant-speed protocols using the linearized 1·time^?1 model. CS and RCP, expressed as speed or metabolic rate, were not significantly different (11.7 ± 2.3 km·h^?1 vs. 11.5 ± 2.3 km·h^?1, p = 0.208; 2.88 ± 0.80 l·min^?1 vs. 2.83 ± 0.72 l·min^?1, p = 0.293) and were significantly correlated (r² = 0.52, p < 0.0001; r² = 0.74, p < 0.0001, respectively). However, there was a high degree of variability between the parameters. The findings of the current study indicate that, while on average CS and RCP were not different, the high degree of variability between these parameters does not permit accurate estimation of one from the other variable and suggests that these parameters may not be physiologically equivalent.     

模拟3500m不同低氧训练模式对大鼠力竭运动后心肌线粒体自由基代谢及呼吸链功能的影响

目的:探讨4种低氧训练模式对大鼠力竭运动后心肌线粒体自由基代谢及呼吸链功能的影响。方法:将雄性Wistar大鼠随机均分为5组,即低住低训组(LoLo)、高住高练组(HiHi)、高住低训组(HiLo)、低住高练组(LoHi)及高住高练低训组(HiHiLo)。以当地环境为基点作为常氧环境,采用低压氧舱模拟低氧环境。依实验方案,各组大鼠分别在常氧或/和低氧环境中居住及递增负荷训练5周,每周训练6 d。各组大鼠在最后1次训练后,在常氧环境中恢复3 d,力竭运动后即刻取心肌样本。用差速离心法提取心肌线粒体,分别测定丙二醛含量、超氧化物歧化酶、谷胱甘肽过氧化物酶和过氧化氢酶(catalase,CAT)活性及呼吸链酶复合体I～IV(CI～IV)活性。结果:与LoLo组相比,心肌组织中HiHi组GSH-Px及CAT活性均显著升高,HiLo组CAT活性显著升高,LoHi和HiHiLo组SOD、GSH-Px及CAT活性均显著升高,4种低氧训练模式MDA含量均显著降低。与LoLo组相比,HiHiLo组心肌线粒体SOD活性显著升高,HiHi、HiLo和HiHiLo组MDA含量均显著降低。与LoLo组相比,HiHi组心肌线粒体CIV活性显著升高,HiHiLo组CI、CII和CIV活性均显著提高,HiHi、LoHi及HiHiLo组CIII活性均显著降低。结论:HiHiLo可能是较好的低氧训练模式。     

补充辅酶Q_（10）与递增负荷运动训练对大鼠肝脏线粒体呼吸链酶复合物活性的影响

目的：探讨补充辅酶Q10与递增负荷运动训练对力竭运动大鼠肝脏线粒体呼吸链酶活性的影响。方法：Wister雄性大鼠36只,随机分为：对照组（NC）、CoQ10补充组（QC）、训练组（NE）、训练＋CoQ10补充组（QE）;QC组和QE组大鼠每天灌胃CoQ10一次,并进行7周递增负荷跑台运动;实验结束时所有大鼠进行一次力竭性跑台运动即刻处死;分光光度计法测定大鼠肝脏线粒体呼吸链酶复合物活性。结果：（1）QC、NE及QE组CⅠ活性均显著高于NC组（P〈0.01或P〈0.001）,QE组CⅠ活性显著高于NE组（P〈0.05）;（2）NE组、QE组CⅡ活性均明显高于NC组（P〈0.01或P〈0.001）,且QE组高于NE组（P〈0.05）;（3）NE组、QE组CⅢ活性均明显高于NC组（P〈0.001）;NE、QE组无明显差异（P〉0.05）;（4）NE组、QE组CⅥ活性明显均高于NC组（P〈0.001）,NE、QE组无显著性差异（P〉0.05）。结论：（1）递增负荷运动训练及运动训练结合CoQ10补充均可提高大鼠力竭运动后即刻肝脏线粒体呼吸链酶复合物活性,改善线粒体完整功能。（2）递增负荷运动训练与补充CoQ10在改善力竭运动后即刻大鼠肝脏线粒体完整功能方面无协同作用。     

股四头肌血红蛋白在间歇运动中的特征分析

目的：探讨在间歇训练局部骨骼肌中肌氧变化特征,包括氧合血红蛋白（HbO2）,还原血红蛋白（Hb）和血流量（BV）,将它们与呼吸系统参数进行比较,期待为间歇训练提供新的辅助监测与评价手段。方法：选取武汉体院学院男子中长跑专业运动员16人在运动医学跑台MERCURY4.0上进行间歇训练。同时使用华中科技大学研发的近红外三波长便携式肌氧监测仪、MAX-II心肺功能仪和P-Lar心率表采集被试对象相关数据,包括HbO2、Hb、BV、VO2、VCO2、RER及心率（HR）,绘制曲线图比较,并对比较结果进行统计检验。结果：肌氧含量与呼吸系参数变化趋势高度相关,HbO2曲线下降速率与呼吸商变化高度相关,BV曲线呈逐级上升趋势,组间变化速率相差不明显。结论：可以利用近红外光谱技术实时监测间歇训练中的局部骨骼肌肌氧含量的相对变化,了解运动员局部运动状态并推测其整体运动状况,有望为间歇训练实时监测与评价提供简便有效的辅助监测手段。     

优秀手球运动员递增负荷期间肺通气和氧通气当量变化特征研究

观察国家优秀手球运动员在递增负荷运动过程中肺通气机能变化,结果发现,运动负荷开始阶段,VERF和TV大幅增长;随着运动负荷的增加,VE、RF和TV出现相对缓慢的增长;大运动负荷期间,VE先发生上升,然后缓慢增长,RF变化与VE相似;通气阈出现在第9min左右;在开始阶段,VE/VO2随着运动负荷的增加而降低,然后,随着运动负荷增加而增加。结论：递增负荷过程中,优秀手球运动员肺通气变化过程分为快速增长阶段、缓慢增长阶段和快速增长平台期。