INTERACTIONS OF CORTISOL,TESTOSTERONE, AND RESISTANCE TRAINING: INFLUENCE OF CIRCADIAN RHYTHMS

Diurnal variation of sports performance usually peaks in the late afternoon, coinciding with increased body temperature. This circadian pattern of performance may be explained by the effect of increased core temperature on peripheral mechanisms, as neural drive does not appear to exhibit nycthemeral variation. This typical diurnal regularity has been reported in a variety of physical activities spanning the energy systems, from Adenosine triphosphate-phosphocreatine (ATP-PC) to anaerobic and aerobic metabolism, and is evident across all muscle contractions (eccentric, isometric, concentric) in a large number of muscle groups. Increased nerve conduction velocity, joint suppleness, increased muscular blood flow, improvements of glycogenolysis and glycolysis, increased environmental temperature, and preferential meteorological conditions may all contribute to diurnal variation in physical performance. However, the diurnal variation in strength performance can be blunted by a repeated-morning resistance training protocol. Optimal adaptations to resistance training (muscle hypertrophy and strength increases) also seem to occur in the late afternoon, which is interesting, since cortisol and, particularly, testosterone (T) concentrations are higher in the morning. T has repeatedly been linked with resistance training adaptation, and higher concentrations appear preferential. This has been determined by suppression of endogenous production and exogenous supplementation. However, the cortisol (C)/T ratio may indicate the catabolic/anabolic environment of an organism due to their roles in protein degradation and protein synthesis, respectively. The morning elevated T level (seen as beneficial to achieve muscle hypertrophy) may be counteracted by the morning elevated C level and, therefore, protein degradation. Although T levels are higher in the morning, an increased resistance exercise–induced T response has been found in the late afternoon, suggesting greater responsiveness of the hypothalamo-pituitary-testicular axis then. Individual responsiveness has also been observed, with some participants experiencing greater hypertrophy and strength increases in response to strength protocols, whereas others respond preferentially to power, hypertrophy, or strength endurance protocols dependent on which protocol elicited the greatest T response. It appears that physical performance is dependent on a number of endogenous time-dependent factors, which may be masked or confounded by exogenous circadian factors. Strength performance without time-of-day–specific training seems to elicit the typical diurnal pattern, as does resistance training adaptations. The implications for this are (a) athletes are advised to coincide training times with performance times, and (b) individuals may experience greater hypertrophy and strength gains when resistance training protocols are designed dependent on individual T response. (Author correspondence: Lawrence.hayes@uws.ac.uk)     

Dietary Patterns,Metabolic Markers and Subjective Sleep Measures in Resident Physicians

Shiftwork is common in medical training and is necessary for 24-h hospital coverage. Shiftwork poses difficulties not only because of the loss of actual sleep hours but also because it can affect other factors related to lifestyle, such as food intake, physical activity level, and, therefore, metabolic patterns. However, few studies have investigated the nutritional and metabolic profiles of medical personnel receiving training who are participating in shiftwork. The aim of the present study was to identify the possible negative effects of food intake, anthropometric variables, and metabolic and sleep patterns of resident physicians and establish the differences between genders. The study included 72 resident physicians (52 women and 20 men) who underwent the following assessments: nutritional assessment (3-day dietary recall evaluated by the Adapted Healthy Eating Index), anthropometric variables (height, weight, body mass index, and waist circumference), fasting metabolism (lipids, cortisol, high-sensitivity C-reactive protein [hs-CRP], glucose, and insulin), physical activity level (Baecke questionnaire), sleep quality (Pittsburgh Sleep Quality Index; PSQI), and sleepiness (Epworth Sleepiness Scale; ESS). We observed a high frequency of residents who were overweight or obese (65% for men and 21% for women; p?=?0.004). Men displayed significantly greater body mass index (BMI) values (p?=?0.002) and self-reported weight gain after the beginning of residency (p?=?0.008) than women. Poor diet was observed for both genders, including the low intake of vegetables and fruits and the high intake of sweets, saturated fat, cholesterol, and caffeine. The PSQI global scores indicated significant differences between genders (5.9 vs. 7.5 for women and men, respectively; p?=?0.01). Women had significantly higher mean high-density lipoprotein cholesterol (HDL-C; p?<?0.005), hs-CRP (p?=?0.04), and cortisol (p?=?0.009) values than men. The elevated prevalence of hypertriglyceridemia and abnormal values of low-density lipoprotein cholesterol (LDL-C; >100?mg/dL) were observed in most individuals. Higher than recommended hs-CRP levels were observed in 66% of the examined resident physicians. Based on current recommendations, a high prevalence of low sleep quality and excessive daytime sleepiness was identified. These observations indicate the need to monitor health status and develop actions to reassess the workload of medical residency and the need for permission to perform extra night shifts for medical residents to avoid worsening health problems in these individuals.     

Equestrian Coaches' Understanding and Application of Learning Theory in Horse Training

ABSTRACT

To assess the knowledge of learning theory among accredited equestrian coaches in Australia, a 20-item questionnaire was distributed to all coaches registered with the National Coaches Accreditation Scheme in Australia (n = 830). Of the 206 respondents, 79.5% considered positive reinforcement to be “very useful,” yet only 2.8% correctly explained its use in horse training. When asked about the usefulness of negative reinforcement, 19.3% of coaches considered it “very useful,” with 11.9% correctly explaining its use. Punishment was rated “very useful” by 5.2% of respondents, although only eight coaches (5.4%) explained punishment correctly. Release of pressure was considered the most effective reward for horses among respondents (78.2%). These results indicate that many equestrian coaches lack a correct understanding of positive and negative reinforcement as they apply to horse training. Given that qualified coaches play a significant role in the dissemination of information on training practices, this highlights the need for improved education of equestrian coaches. Education to remedy this situation has the potential to enhance the welfare of horses through reduced behavioral conflict and improve training outcomes.     

Effectiveness of using an unskilled model in action observation combined with motor imagery training for early motor learning in elderly people: a preliminary study

Abstract

Aim of the study: To investigate a more available model for the early phase of motor learning after action observation combined with motor imagery training in elderly people. To address the purpose, we focused on a slow, unskilled model demonstrating an occasional error.

Materials and methods: A total of 36 elderly people participated in the current study and were assigned to either the unskilled or skilled model observation groups (n?=?12, respectively), or the control group (n?=?12). The participants in the observation groups observed the assigned a video clip of an unskilled or skilled model demonstrating a ball rotation task. During the observation, the participants were instructed to imagine themselves as the person in the video clip. The participants in the control group read a scientific paper during the equivalent period of action observation and motor imagery. We measured ball rotation performance (the time required for five rotations, the number of ball drops) in pre- and post-intervention (observation combined with motor imagery training for intervention groups or reading for control group).

Results: Ball rotation performance (ball rotation speed) significantly improved in the unskilled model observation group compared to the other two groups.

Conclusions: Intervention for action observation using unskilled model combined with motor imagery was effective for improving motor performance during the early phase of motor learning.     

我院两类人员333制并轨培养效果评价

??目的 了解住院医师和专业学位研究生333制并轨培养的效果。方法 对实施333制管理模式前后的住院医师与专业学位研究生进行年度考核,比较考核成绩。结果 实施333制管理模式前,专业学位研究生考核成绩与住院医师有统计学差异,经过一年的并轨培养,专业学位研究生考核成绩显著提高,与同年住院医师考核结果无统计学差异。结论 专业学位研究生在住院医师规范化培训基地与住院医师进行并轨培养,能够提高专业学位研究生的临床能力。     

康复训练对脑缺血大鼠运动功能恢复和脑组织cAMP-PKA信号通路的影响

目的观察康复训练对脑缺血再灌注大鼠运动功能及缺血灶周边脑组织cAMP、PKA表达的影响,探讨康复训练促进缺血性脑卒中运动功能恢复的分子机制。方法采用Longa改良线栓法制备大鼠大脑中动脉缺血再灌注模型（middle cerebral artery ischemia-reperfusion model,MCAO）,选择Bederson标准评分为1-3分的模型大鼠42只,随机分为自然恢复组（n=24）、康复训练组（n=18）,同时设立假手术组（n=12）。康复训练组大鼠于MACO术后48 h开始每天给予平衡木、转棒及滚筒训练。酶联免疫法（ELISA）检测缺血灶周围脑组织cAMP、PKA蛋白的表达,平衡木及网屏试验评定大鼠的运动功能。结果 （1）康复训练组缺血灶周围脑组织cAMP、PKA表达在术后7、14、21d均明显高于自然恢复组;（2）康复训练组大鼠的运动功能较自然恢复组明显改善。结论康复训练促进脑缺血再灌注大鼠的运动功能恢复,可能与cAMP-PKA信号通路活动有关。     

海军两栖侦察队女队员海练前后内分泌性激素变化及月经失调影响因素分析

目的：通过监测海军陆战旅两栖侦察队女队员海练前后内分泌性激素的变化,观察海练对女性生理功能的影响。方法：海军陆战队某旅两栖侦察队女队员30名,按侦察兵训练大纲的标准于每年6～7月进行海练,每天训练7h,共60d。于海练前1d、海练后1d和海练后第90d抽血,采用微粒子酶联免疫法测定其血清促卵泡生成素、促黄体生成素、雌二醇、孕酮、泌乳素和睾酮的水平;通过问卷调查了解女陆战队员身高、体重、月经周期变化和营养等状况,并进行健康宣教和心理干预。结果：女队员海练后1d较海练前1d内分泌性激素水平显著降低,差异具有统计学意义（P〈0．05）;海练后1d,女队员月经失调的情况明显增多（P〈0．05）;海练后第90d内分泌性激素水平较海练后1d显著升高,差异具有统计学意义（P〈0．05）;海练后第90d,女队员月经失调的情况显著改善（P〈0．05）。结论：在高温高湿环境下长途奔袭、渡海、抢滩登陆等高强度海练造成的女陆战队员内分泌性激素水平改变及月经失调,可通过适当调整训练量和强度、平衡饮食保证能量供应、实施心理干预等措施降低其发生率,这为科学海练提供了依据,同时可预防运动性月经失调的发生。     

Paint and Paper Creations

This article investigates generalist kindergarten teachers’ academic music training based on data collected from students undertaking an undergraduate degree in preschool (kindergarten) education (students aged 4–6 years) in Greece. The study was carried out through a questionnaire survey that addressed students’ aspirations when entering the university and the real learning outcomes by the end of their studies. This article seeks to find relationships between students’ academic experiences and their level of confidence and enthusiasm to teach music in kindergarten. The findings suggest that higher education provides students with most of the learning outcomes that they anticipate. However, students lack adequate practical experiences in terms of observing lessons in real educational settings, which can significantly affect their confidence levels. Finally, the author explores some implications for higher education policy and teaching practice.     

Effects of gradual coronary artery occlusion and exercise training on gene expression in swine heart

Gradual occlusion (O) of the swine left circumflex coronary artery (LCX) with an ameroid occluder results in complete O within 3 weeks, collateral vessel development, and compensatory hypertrophy. The purpose of this investigation was to determine the independent and combined effects of O and exercise training (E) on gene expression in the swine heart. Adult Yucatan miniature swine were assigned to one of the following groups (n = 6–9/group): sedentary control (S), exercise-trained (E), sedentary swine subjected to LCX occlusion (SO), and exercise-trained swine with LCX occlusion (EO). Exercise consisted of progressive treadmill running conducted 5 d/wk for 16 weeks. Gene expression was studied in myocardium isolated from the collateral-dependent left ventricle free wall (LV) and the collateral-independent septum (SEP) by RNA blotting. E and O each stimulated cardiac hypertrophy independently (p < 0.001) with no interaction. O but not E increased atrial natriuretic factor expression in the LV, but not in the SEP. E decreased the expression of β-myosin heavy chain in the LV, but not in the SEP. E retarded the expression of collagen III mRNA in SEP; but not in the LV. Exercise training and coronary artery occlusion each stimulate cardiac hypertrophy independently and induce different patterns of gene expression.     

Alterations of β3-adrenoceptors expression and their myocardial functional effects in physiological model of chronic exercise-induced cardiac hypertrophy

Physical training induces cardiovascular autonomic nervous system regulation adaptations, which could result from β adrenergic receptor (AR) modifications. Among them, β₃ AR alterations have been recently reported but their functional effect remained to discuss. To explain the β₃ AR gene expression in relation to function, we simultaneously studied the left ventricle (LV) β₃ AR mRNA and protein levels and the myocardial functional effects of a β₃ AR agonist following physical training. Forty rats were assigned to either a control (C; N = 20) or a trained (T; N = 20) group. The treadmill running protocol was performed for 8 weeks. Histological measurements on LV slices were quantified. The β₃ AR mRNA abundance was studied with RT-PCR and β₃ AR protein density with Western-Blot analysis. Myocardial functional effects of a β₃ AR agonist, BRL37344 (10⁻⁸ M), were studied in Langendorff-perfused hearts. Histological data confirmed the adapted patterns of the physiological cardiac hypertrophy observed in T (P < 0.01), with a significant increase in arteries density (P < 0.01) and an unchanged collagen concentration. The β₃ AR protein density was increased in T (154 ± 38% in T vs. 100 ± 24% in C; P < 0.05), but no change was noted concerning the β₃ AR mRNA level. After BRL37344 perfusion LVDP, +dP/dT and −dP/dT, in C (P < 0.01), and only +dP/dT in T (P < 0.05) were decreased. Moreover, all LV hemodynamic parameters were more altered after BRL37344 in C than in T (P < 0.01). Thus, in this physiological model of cardiac hypertrophy, an increase of β₃ AR density without β₃ AR mRNA alteration was observed. Classical negative myocardial lusitropic and inotropic effects induced by a specific agonist of β₃ AR were diminished in trained rats.