Strength-velocity relationship and fatiguability of unilateral versus bilateral arm extension

Summary Strength-velocity relations and fatigue resistance in an arm bench press manoeuvre were compared between conditions of bilateral (BL, both arms acting together) and unilateral muscle contraction in 9 young men. BL and UL (sum of the 2 arms acting singly) strength was similar for isometric and slow isokinetic maximal voluntary contractions (MVC); at high velocities BL MVC declined more than UL. In both types of contractions a curvilinear relation was observed between strength and velocity, with significantly higher peak torques (PT) being produced under isometric conditions than for slow velocity efforts (p<0.01). Mean declines in PT during 100 repetitive MVCs of approximately 70s were to 25% of initial values for the BL fatigue test and to 37% for UL (p<0.01). In contrast to results of a similar investigation of leg extension in the same subjects, the arms showed (1) no BL deficit of strength in the initial part of the strength-velocity curve and (2) approximately twice as much fatigue in repetitive contractions. These physiological differences may stem from the varying habitual activity patterns of the arms and legs.     

Airway inflammation in asthma and perennial allergic rhinitis. Relationship with nonspecific bronchial responsiveness and maximal airway narrowing

BACKGROUND: Eosinophilic airway inflammation is the hallmark of asthma, but it has also been reported in other conditions such as allergic rhinitis. We have tested whether the analysis of cells and chemicals in sputum can distinguish between patients with mild allergic asthma, those with allergic rhinitis, and healthy controls. The relationship between inflammation markers in sputum and nonspecific bronchial hyperresponsiveness to methacholine (BHR) (PD20 and maximal response plateau [MRP] values) was also evaluated. METHODS: We selected 31 mild asthmatics and 15 rhinitis patients sensitized to house-dust mite. As a control group, we studied 10 healthy subjects. Every subject underwent the methacholine bronchial provocation test (M-BPT) and sputum induction. Blood eosinophils and serum ECP levels were measured. Sputum cell differentials were assessed, and eosinophil cationic protein (ECP), tryptase, albumin, and interleukin (IL)-5 levels were measured in the entire sputum supernatant. RESULTS: Blood eosinophils and serum ECP levels were higher in asthma patients and rhinitis than in healthy controls, but no difference between asthma patients and rhinitis patients was found. Asthmatics had higher eosinophil counts and higher ECP and tryptase levels in sputum than rhinitis patients or control subjects. Sputum albumin levels were higher in asthmatics than in controls. Rhinitis patients exhibited higher sputum eosinophils than healthy controls. An association between sputum eosinophil numbers and MPR values (r= -0.57) was detected, and a trend toward correlation between sputum ECP levels and PD20 values (r= -0.47) was found in the rhinitis group, but not in asthmatics. No correlation between blood eosinophilic inflammation and lung functional indices was found. CONCLUSIONS: Induced sputum is an accurate method to study bronchial inflammation, allowing one to distinguish between rhinitis patients and mildly asthmatic patients. The fact that no relationship was detected between sputum inflammation and BHR suggests that other factors, such as airway remodeling, may be at least partly responsible for BHR in asthma.     

Sensitivity and maximal response to methacholine in perennial and seasonal allergic rhinitis

Background Airway hyperresponsiveness to pharmacological agonists is a common feature in subjects with allergic rhinitis.
Objective The aim of this study was to investigate differences in threshold value and shape of the concentration-response curves to methacholine between subjects with perennial allergic rhinitis and subjects with seasonal rhinitis.
Methods We studied a sample of 72 non-asthmatic patients with allergic rhinitis. They were subdivided into two groups: subjects with only seasonal symptoms and skin sensitization to grass and/or Parietaria pollen allergens (seasonal group, n = 38), and subjects with perennial symptoms and skin sensitization to house dust mite, alone or with other allergens (perennial group, n = 34). They were challenged with methacholine (up to 200mg/mL), and concentration-response curves were characterized by the threshold value (PC₂₀= provocative concentration of methacholine required to produce a 20% fall in FEV₁) and maximal response plateau, if possible. The measurements in the seasonal group were done within the pollen season.
Results The geometric mean methacholine PC₂₀ for subjects of the perennial group was 6.9mg/mL, compared with 23.4mg/mL in subjects of the seasonal group ( P 0.01). A plateau response was detected in 16 subjects of the perennial group and in 28 subjects of the seasonal group (p 0.05). Moreover, the level of plateau was higher in subjects of the perennial group when compared with subjects of the seasonal group (23.8 ±2.0% vs 19.2 ±1.6%, P 0.05).
Conclusion In subjects with allergic rhinitis, sensitization to perennial allergens is associated not only with lower methacholine threshold values, but also with lower prevalence and higher level of plateau than sensitization to pollen allergens.     

Increased left ventricular muscle mass after long-term altitude training in athletes

The effects of long-term altitude training on altitude and sea-level physiological characteristics in elite endurance athletes were investigated. Seven Swedish elite cross-country skiers (five men, two women; mean age 27 years) spent 1 month training at 1900 m above sea level in Italy. Rollerski treadmill tests were performed before and 5 and 11 days after the altitude sojourn; three tests were also performed at altitude. Before and 1, 11 and 35 days after the altitude camp, echocardiographic and blood volume measurements were performed. The heart rates at both maximal (P < 0.05) and submaximal (P < 0.01) work loads were decreased by 5–9 beats min^?1 at altitude. The haemoglobin concentration and haematocrit increased quickly at altitude with a corresponding decrease on return to sea level. The blood volume (7%) and total haemoglobin (3%) tended to be higher day 11 post-altitude (NS). There were no significant changes in diastolic internal diameter or wall thickness of the left ventricle, but the calculated cardiac left ventricular muscle mass was increased post-altitude (9–10%, P < 0.01). The maximal oxygen uptake increased in six of the seven skiers after the altitude training (day 11, mean 3%, NS). In conclusion, training at moderate altitude may cause a reduction in heart rates during exercise. Moreover, after long-term training at altitude, there may be an increase in the cardiac left ventricular muscle mass.     

A grounded theory of inspirational coach leadership

The purpose of this study was to develop a grounded theory of the process of inspirational coach leadership in sport. A Straussian grounded theory methodology was used. Semi‐structured interviews and focus groups were conducted with athletes (n = 22) and coaches (n = 15). Data were analyzed through a process of open and axial coding, and theoretical integration. Through the process of analysis, data were broken down into smaller units (concepts), relationships between concepts were identified, and a substantive grounded theory was developed. The grounded theory of inspirational coach leadership was built around the core category of “athlete(s) inspired through changed awareness of their capabilities.” The core category was underpinned by three categories: (a) establishment of mutual trust and respect with athletes, whereby coaches need to establish trust with athletes in order to inspire athletes; (b) conditions under which inspiration has the potential to occur, which highlighted that athletes are inspired in situations where they are vulnerable or ignorant regarding their potential; and (c) coach acts to change athlete's awareness of their capabilities, which denotes the specific behaviors coaches should display to inspire athletes in such conditions. The theory also highlights that a range of contextual factors relating to the coach, athletes, and performance‐environment interact to impact upon the process. The theory predicts that consistency between coach behavior and the conditions in which inspiration can occur will lead to athlete inspiration, but only if the coach has established a foundation of trust and respect with the athlete.     

新加坡青少年道德教育及对中国的启示

新加坡能够在三十年间创造惊人奇迹的原因是多方面的 ,其中的青少年道德教育起到了举足轻重的作用。新加坡的青少年道德教育具有其鲜明的特色。中国与新加坡在文化渊源等方面具有相似之处 ,对于转型时期的中国来说 ,研究新加坡青少年道德教育会极具现实运用价值     

美国和瑞典国家生命伦理委员会建设的经验与启示

美国和瑞典都有自己的国家伦理委员会。充足的资金来源、恰当的定位与合理的人员组成、有保障的权力与威信、信息公开与公众参与、合理分工是其成功的基本经验。建议借鉴西方发达国家的经验,成立隶属于国务院领导、直接为国务院总理在生命科学研究的重大问题上,提供决策咨询意见的国家生命伦理委员会。     

Comparative effects of resistance training on peak isometric torque, muscle hypertrophy, voluntary activation and surface EMG between young and elderly women

We compared the effect of a 10-week resistance training program on peak isometric torque, muscle hypertrophy, voluntary activation and electromyogram signal amplitude (EMG) of the knee extensors between young and elderly women. Nine young women (YW; range 20-30 years) and eight elderly women (EW; 64-78 years) performed three sets of ten repetitions at 75% 1 repetition maximum for the bilateral leg extension and bilateral leg curl 3 days per week for 10 weeks. Peak isometric torque, EMG and voluntary activation were assessed before, during, and after the training period, while knee extensor lean muscle cross-sectional area (LCSA) and lean muscle volume (LMV) were assessed before and after the training period only. Similar increases in peak isometric torque (16% and 18%), LCSA (13% and 12%), LMV (10% and 9%) and EMG (19% and 21%) were observed between YW and EW, respectively, at the completion of training (P<0.05), while the increase in voluntary activation in YW (1.9%) and EW (2.1%) was not significant (P>0.05). These findings provide evidence to indicate that participation in regular resistance exercise can have significant neuromuscular benefits in women independent of age. The lack of change in voluntary activation following resistance training in both age groups despite the increase in EMG may be related to differences between measurements in their ability to detect resistance training-induced changes in motor unit activity. However, it is possible that neural adaptation did not occur and that the increase in EMG was due to peripheral adaptations.     

吐纳呼吸操联合穴位贴敷治疗支气管哮喘慢性持续期临床观察

目的 观察吐纳呼吸操联合穴位贴敷治疗哮喘慢性持续期的临床疗效。方法 将60例哮喘慢性持续期患者随机分成对照组和观察组,每组30例;对照组予常规西药治疗配合穴位贴敷,观察组在对照组基础上加用吐纳呼吸操,疗程均为6周;治疗后3个月随访时,记录两组哮喘急性发作次数及呼吸道感染次数;治疗前、治疗后及随访时,采用哮喘控制测试问卷（asthma control test,ACT）评价哮喘控制水平,采用肺功能中用力肺活量（forced vital capacity,FVC）、第1秒用力呼气容积（forced expiratory flow in one second,FEV1）、呼气峰值流量（peak expiratory flow,PEF）占预计值的百分比（FVC%、FEV1%、PEF%）和呼出气一氧化氮（fractional exhaled nitric oxide,FeNO）检测仪评估患者气道通气功能及炎症程度,采用哮喘生活质量量表（asthma quality of life questionnaire,AQLQ）评估患者生活质量。结果 治疗后3个月,观察组哮喘急性发作次数和呼吸道感染次数均低于对照组（P<0.05）。治疗后、随访时,两组ACT评分、FVC%、FEV1%、PEF%、FeNO及AQLQ中活动受限、哮喘状况、心理状况和对刺激原的反应4个维度评分均优于治疗前（P<0.05）,且治疗后观察组各项均显著优于对照组（P<0.05）,随访时观察组ACT评分、FEV1%、FeNO及AQLQ中活动受限、哮喘状况、心理状况3个维度评分优于对照组（P<0.05）。结论 采用吐纳呼吸操联合穴位贴敷治疗能显著提高哮喘慢性持续期患者症状控制水平和肺功能水平,缓解哮喘气道炎症,改善生活质量。