采用脑生物电诱发试验诊断优秀运动员中枢疲劳

目的:为备战第19届冬奥会,对国家短道速滑队、花样滑冰队主力队员进行脑电图(EEG)、脑电地形图(BEAM)、压缩谱阵图(CSA)跟踪监督,评定竞技状态、诊断中枢疲劳.方法:采用运动表象心理诱发试验、过度换气诱发试验和无创伤性的大脑神经元突触后放电测定脑内神经化学传递物质的方法,跟踪监测了国家短道速滑、花样滑冰队员17名,测试110人次.结果:(1)根据诱发条件下脑电波频率和幅度的改变可以判断运动训练过程中运动员的速度、力量素质.(2)脑功率谱能量比值可以反映对训练强度的应激水平.(3)通过运动表象心理诱发试验发现功能性改变为81.82%,通过过度换气诱发试验发现功能性改变为90.91%.唤醒水平适度呈现最佳状态,唤醒水平过高呈紧张状态是诊断先兆疲劳的指征,唤醒水平受到抑制诊断为中枢疲劳.(4) 脑内神经递质测定显示:疲劳状态下,多巴胺显著下降,γ-氨基丁酸和5-羟色胺明显增加.     

优秀跳水运动员赛前脑功能训练适应状态的量化分析

目的:了解跳水运动员赛前运动训练适应状态的特点,探讨其神经生理学特征。方法:利用高级运动训练状态监控仪采集26名备战第12届全国运动会的跳水运动员赛前不同阶段90个样本的脑电(EEG)α波的功率谱值,同时采集其训练计划完成情况等相关数据,采用自组织特征映射(SOM)神经网络聚类分析的方法对其训练适应状态进行分类,并对不同状态运动员的相关指标进行统计分析。结果:优秀跳水运动员的脑电α波功率谱主要集中于10 Hz,国际健将与健将之间的功率值无显著性差异;脑信息熵的变化值与运动成绩的变化值呈中等强度负相关关系(P<0.05);状态一般运动员赛前8 Hz水平显著高于状态优秀运动员(P<0.05),而10 Hz水平显著低于状态优秀运动员(P<0.05)。结论:国际健将与健将之间脑电α波序参量水平差异不显著,无法直接辨别出适应状态的差异;通过脑信息熵的变化可以推测运动员一段时间的运动成绩,即熵值减小,则运动表现更好;SOM聚类分析方法可以将不同训练适应状态的运动员进行分类。     

优秀男子短距离场地自行车运动员脑电变化分析

目的:观察不同水平男子短距离场地自行车运动员脑电变化,为探讨自行车运动员技术动作发挥的中枢机制提供依据.方法:研究对象为8名二级和7名健将级男子自行车运动员,应用脑电图(EEG)仪测试受试者在安静闭目和表象1公里场地计时赛时的脑电变化.结果:(1)安静时,二级运动员和健将级运动员EEG的功率谱成对称性分布,且两组运动员的EEG对应各区总功率无显著性差异(P＞0.05).(2)表象时,二级运动员EEG发生去同步化,但健将级运动员EEG的功率谱成对称性分布.(3)二级运动员左、右侧顶区与枕区α指数比值表象与安静状态下相比均无显著性差异(P＞0.05),健将级运动员左、右侧有显著性差异(P＜0.05).(4)安静时,健将级运动员顶区和枕区脑电活力比值(β/α,%)与二级运动员比较无显著性差异(P＞0.05);表象时,两组运动员脑电活力比值有显著性差异(P＜0.05).结论:健将级男子短距离场地自行车运动员中枢神经系统对外界信息的整合及技术动作协调能力优于二级运动员.     

中国优秀跳水运动员大脑机能监控研究

目的 :把握跳水运动员在大赛前训练时的神经机能情况与训练水平。方法 :利用脑电图和脑地形图技术对中国跳水运动员进行训练监控。结果 :2次对 11名主力队员进行脑功能检测 ,表象竞赛时自选动作的大脑唤醒水平值 (43 79± 2 96 )略高于规定动作 (42 37± 2 2 6 ) ,自选动作能量比值 (1 74 9± 0 373)亦略高于规定动作 (1 6 32± 0 36 4) ,其中 ,女运动员第 2次检测时自选动作的大脑唤醒水平值明显高于规定动作。结论 :(1)脑功能检测结果表明 ,女运动员神经机能状态略优于男队员 ,而男运动员中有 2名已处于紧张状态。 (2 )与其他项目 ,如乒乓球、短道速滑等相比 ,优秀跳水运动员大脑唤醒水平 (兴奋性 )值相同 ,但能量比值较低 ,可能是跳水项目的特点。     

优秀乒乓球运动员神经调节机能特征

采用脑电生理学和心理学相互结合而形成的神经－心理学方法，共检查了国家乒乓球队运动员７４例（８７人次），对其神经调节机能给予客观评价。结果表明：脑电图Ａｌｐｈａ活动能反映乒乓球不同打法与大脑神经元代谢的方式，其符合率达８０％以上。受试者在表象竞赛时，快攻者，波率加快（速度），弧圈者，波幅升高（强度），快弧者，大脑神经元的代谢方式以速度强度交替的形式出现；Ａｌｐｈａ指数被抑制的百分数能反映集中注意力，并可判断运动能力，不同训练水平的运动员之间有显著性差异Ｐ＜０．００１；节律性闪光刺激诱发试验，提供了诊断精神疲劳的客观指标，并提高了诊断精神疲劳的阳性率。     

乒乓球运动员发球动作识别时的神经效率——来自EEG的证据

目的:探讨乒乓球运动员识别发球动作时具有大脑皮层活动减少的特征。方法:采用64导脑电测试系统记录18名乒乓球运动员和18名乒乓球初学者观看发球旋转的动作视频时的脑电数据,共有160个发球动作视频,在视频结束时被试进行旋转的判断,基于事件前的脑电基值,计算在动作识别过程中alpha频率的事件相关去同步化(ERD),了解大脑皮层激活状态的变化。结果:与运动新手相比,运动专家在动作识别过程中高频alpha(10.5~12.5 Hz)的ERD幅度更低。与运动新手相比,运动专家在正确识别发球动作时高频alpha频段的ERD在顶叶皮层(P<0.05)和枕叶皮层的幅值更低(P<0.01)。结论:乒乓球运动员专项动作识别存在神经效率,与更低幅度alpha频率的ERD相联系。乒乓球运动员发球动作识别时大脑顶叶和枕叶的能量消耗较小。     

心算任务复杂度对脑电theta,alpha和beta波的影响

目的以1Hz为频宽单位比较两种复杂度心算任务下4～30Hz范围的脑电功率谱,分析其与文献中以经典脑电波段划分所得结果的关系。方法14名健康志愿者完成两种复杂度的心算任务,同步采集其脑电数据。对前额和顶叶区域内10个代表性通道预处理后的脑电数据采用Welch算法实现谱估计,相对基线期做归一化处理,获得两种复杂度心算任务下的相对功率谱密度,并逐一配对t检验每1Hz频宽单位内功率谱差异的显著性。结果前额和顶叶区域能体现心算任务复杂度差异的脑电信号精细频率范围分别为10～25Hz和9～25Hz(P0.05)。结论较高频段alpha波和较低频段beta波能较好地表征心算任务的复杂度,以1Hz为频宽单位对脑电功率谱的精细区间分析是对基于经典脑电节律划分分析的一种补充。     

定量脑电图适宜采样时间的选取

定量分析脑电图(EEG)时的采样时间以多么长为宜,众说不一。笔者通过分析不同时间枕区主频段的频率和功率,探讨定量EEG最佳采样时间。 1 对象和方法 受试者38人,均为健康者,男29人,女9人。年龄18～49岁。应用日本光电ME-17脑电仪与国产DYD-500型脑地形图仪。按常规EEG检查方法,采集单极导联,采样总时间160s,采样频率100Hz,分析精度±0.15 Hz。选用6s、30s、60s、90s、120s、150s 6种不同时间段的脑电作EEG枕区功率谱主频段的频率和功率分析。     

经皮穴位电刺激对大脑神经功能活动影响研究进展

传统中医经脉穴位针灸调节机体生理功能有着重要作用,通过定量物理刺激穴位手段来探索大脑高级神经活动的机制受到关注。从经皮穴位电刺激、基于脑电和功能磁共振成像构建脑功能网络、脑电功率谱密度、相位同步性、复杂度特征和默认模式网络及各种客观变量(如针刺方式)影响等方面回顾了该领域的研究现状、存在问题;归纳小结了有关研究进展及其在脑电θ波段同步性、子频带能量变化、默认模式网络以及针对多穴位协同研究较少且结果模糊等不足之处。     

200例颅脑损伤脑电地形图观察

我们采用脑电图(EEG)及脑电地形图(BEAM),结合计算机断层扫描(CT)检查,对200例颅脑损伤患者进行脑功能检查,脑形态学检查,现分析如下:1 资料与方法1.1 临床资料 本组200例,男123例,女77例,年龄8～76岁,其中20～60岁156例,占78％,20岁以下44例,占22％。按我国颅脑损伤分型标准分为轻、     

A survey of badminton injuries.

A Badminton Injury Questionnaire (BIQ) was developed to survey the type and frequency of injuries that are likely to occur from playing competitive badminton. Two hundred and thirty-one players, ranging from club players to international champions, completed the survey which indicated an injury incidence rate of .09 and .14 injuries per person per year for male and female badminton players respectively. Badminton participation resulted in relatively few injuries, most of which were cramps, blisters, strains and sprains of the lower extremities and a surprisingly low incidence of tennis elbow.     

Body composition of table tennis players: comparison between performance level and gender

The purpose of this study was to compare whole-body and segmental body composition variables of trained Brazilian table tennis players, according to different performance levels and gender. Sixty-four table tennis players (45 male and 19 female) were distributed in three groups according to performance level: international level players (ILP; 12 male; 8 female), national level players (NLP; 14 male; 6 female) and regional level players (RLP; 19 male; 5 female). The anthropometry measurements and body composition analysis were performed using Dual energy X-ray absorptiometry. Male players demonstrated higher fat-free mass (FFM), and lower fat mass (FM) and body fat percentage (%BF, p < 0.05) compared to female players in all competitive levels, however, non-significant differences were found between whole-body composition and performance level. In the comparison between the dominant and non-dominant arms, FFM, fat-free soft tissue mass (FFSTM) and bone mineral density (BMD) were higher in the dominant arm (p < 0.05) compared to the non-dominant arm in all competitive levels, however, the male ILP group presented lower FFM and FFSTM in the dominant arm compared to the NLP, while the female ILP group presented higher BMD compared to the NLP and RLP. In conclusion, male table tennis players presented higher FFM and lower FM and %BF than female players and the dominant arm presented higher FFM and BMD than the non-dominant, possibly due to the mechanical impact-load imposed by time of table tennis practice.     

Survival estimates for elite male and female Olympic athletes and tennis championship competitors

In this paper, we report survival estimates for male and female Olympic medal winners and for male and female finalists at the British and U S national tennis championships. We find a consistent longevity advantage of Olympic medal‐winning female athletes over Olympic medal‐winning male athletes competing separately in the same events since 1900 and for female finalists over male finalists competing separately in the finals of the national tennis championships of Britain and of the United States since the 1880s. This is the case for sample mean comparisons, for Kaplan–Meier survival function estimates, including life expectancy, and for Cox proportional hazard estimates, which show statistically significant lower hazard rates for women with birth year and other variables constant. The female longevity advantage over males is similar in the early period samples (birth years before1920) and in the full period samples, and is 5–7 years.     

Motivational climate and goal orientations as predictors of perceptions of improvement, satisfaction and coach ratings among tennis players

One purpose of this work was to study the relationship of goal orientations and the perceived motivational climate created by the coach in relation to 219 competitive Spanish tennis players': a) perceived improvement in different facets of the game, b) satisfaction with their competitive results, overall level of play, and coach, and c) ratings of their coach. The second purpose was to examine whether the dependent variables were best predicted by the perceived situationally emphasized goal structure created by the coach and/or the athletes' dispositional goal perspective. Intermediate (N=70), advanced (N=124), and professional (N=25) level players completed Spanish versions of the TEOSQ and the PMCSQ-2 and items assessing perceived improvement specific to tennis, satisfaction and coach ratings. The results were consistent with the tenets of goal perspective theory and provide further support for the promotion of a task involving atmosphere in sport.     

Changes in bone mineral content with decreased training in competitive young adult tennis players and controls: a prospective 4-yr follow-up.

PURPOSE: The purpose of this 4-yr prospective follow-up study of male tennis players was to determine the changes in the playing-to-nonplaying arm differences in bone mineral content (BMC) and answer two questions: 1) Are training induced bone gains lost with decreased training? and 2) Are the possible bone changes related to the changes in training? METHODS: Subjects were 13 former competitive male tennis players and their 13 controls. The players had started their playing career at the mean age of 11 yr. The initial comparisons between the playing and contralateral arms' BMC were done in 1992 (mean age 26 yr), and follow-up was performed 4 yr later. The players were competing at the national top level in the beginning of the study, and all had retired from the top tennis (mean) 2.3+/-0.6 yr before follow-up. Accordingly, they had reduced the average training frequency from 5.2 times a week to 2.6 times a week and the mean hours of training per week from 7.6 to 3.3. RESULTS: The 1996 measurements revealed that on average the players' exercise-induced bone gain in the playing arm had not disappeared with time despite decreased average playing activity and that observed bone changes were not related to changes in training. The side-to-side BMC differences were largest in the humeral shaft (25% in 1992 and 26% 4 yr later) and the proximal humerus (19% and 18%). The radial shaft difference was 14% and the distal radius difference 13% in both 1992 and 1996. In controls, the side-to-side BMC differences were small, less than 5%, and they did not change by time. CONCLUSIONS: In conclusion, this study suggests that bone gain obtained by regular tennis training does not disappear by time despite decreased playing activity. Regular exercise can be valuable for maximizing peak bone mass and thus contributing to prevention of osteoporosis and related fractures later in life.     

A comparison of heart rate responses in racquet games.

The present study investigated the heart rate response to playing tennis with special reference to the skill levels and ages of the participants. Data obtained in a similar manner during earlier studies of badminton and squash players were compared with that obtained during tennis. The number of rallies, mean rally time and actual playing time in 30 minutes of play was also compared for the different skill levels and sports. Results showed that playing tennis raised the players' heart rates to 68-70% of their predicted maximum heart rate (PMHR). Playing squash and badminton could raise heart rates to 80-85% of the players' PMHR which was significantly higher than the values obtained for tennis. The actual skill level of the participants within their chosen sport did not have a significant effect in predicting the physical demands of squash or tennis but was important in predicting the heart rate response of badminton players. The more skillful the badminton player the greater the cardiac response as a result of game play. Analysis of time spent in actual play revealed that tennis players were involved in play for only five of the thirty minutes of game play, compared to 15 and 10 min respectively for squash and badminton. Skill level within each sport was only a significant factor in predicting length of play for squash players in which the medium and highly skilled groups played significantly longer than those of a lower level of skill.     

Effect of ballistic and power training on performance adaptations of élite table tennis players

The purpose of this study was to examine the effects of ballistic and power training on the skills, physical fitness and body composition adaptations of élite table tennis players. Thirty male table tennis players (age: 24?±?7 years, stature: 175?±?6 cm, body mass 74?±?16 kg, percentage of fat mass (%FM) 12?±?7%, mean?±?SD), who were able to perform top spin strike properly, were randomly assigned to three groups: power training (PT), ballistic training (BT) and no training (Control, CON). PT and BT trained 3 times per week for 8 weeks. PT consisted of three sets for six different stations, 60–80% of one repetition maximum (1RM). BT consisted of three sets for five different throwing exercises. Pre- and post-intervention group comparisons were analyzed using a two-way ANOVA with repeated measurements of two factors (group?×?time). After training, significant interactions were observed in increasing muscle strength, muscle endurance, explosive power, anaerobic power, agility and grip strength regardless of the exercise methods (p?<?0.05). Moreover, both training regimens were not effective in changing body composition, reaction time and skills (p?>?0.05). In conclusion, the results of the present study suggest that physical fitness adaptations can be increased similarly after 8 weeks of power and ballistic training, in table tennis players. So coaches and elite table tennis players can use ballistic and power training to improve their performance without having to worry about the negative impact of their training on their skill and explosive power performance.

     

Intensity of tennis match play

This review focuses on the characteristics of tennis players during match play and provides a greater insight into the energy demands of tennis. A tennis match often lasts longer than an hour and in some cases more than five hours. During a match there is a combination of periods of maximal or near maximal work and longer periods of moderate and low intensity activity. Match intensity varies considerably depending on the players' level, style, and sex. It is also influenced by factors such as court surface and ball type. This has important implications for the training of tennis players, which should resemble match intensity and include interval training with appropriate work to rest ratios.