我国自由式滑雪运动员运动技能学习心理控制的实验研究

研究目的构建空中技巧项目技能学习心理结构和助滑速度最佳训练控制方案与效果的评定.研究方法心理测量法、心理技能训练与评定方法、心理训练与技术训练结合.主要研究结果与结论经13个月技能学习心理控制方案的实施,运动员技术水平稳步发展;技能学习心理控制的准确性是随着动作难度的增加而加强,助滑速度的范围是随着动作难度的增大可调控的范围变小,运动员动作成功率取决于最佳助滑速度知觉、空中技术及着陆的调控能力.     

现场监测与反馈对自由式滑雪空中技巧运动员助滑速度知觉控制能力的影响

运用现场监测与反馈训练的研究方法，对自由式滑雪空中技巧国家集训队运动员进行助滑速度知觉控制训练。结果表明：在所构建的最佳助滑速度控制范围之内进行24次水池和16次雪上交替控制训练课后，运动员助滑速度知觉控制能力明显提高；助滑速度知觉控制能力与运动成绩呈高度相关，说明助滑速度知觉控制能力是提高动作成功率和运动成绩的基础因素之一。     

空中技巧助滑速度运用的力学原理

为进一步认识自由式滑雪空中技巧运动规律,通过测量法、统计法对2004"龙珠杯"铃木自由式滑雪国际雪联世界杯的各国参赛运动员的助滑速度进行分析,运用力学原理阐述助滑速度在空中技巧运动中的运用.得出结论:不同翻转周数、不同动作难度助滑速度不一样.以动量矩守恒定律为依据;起跳阶段的助滑速度主要以圆周运动中向心力的作用原理来调节,空中姿势的改变根据动量矩守恒定律可调节速度;空中技巧项目运动员需要有精确的速度感知能力.     

自由式滑雪空中技巧项目助滑距离与速度控制研究

研究在各种雪质及环境条件下,运动员助滑速度与助滑距离的关系,建立助滑距离与速度控制模型。最终向运动队提供各种条件下运动员适宜助滑距离的参考值,以达到控制助滑速度,获得最佳动作效果的目的。该模型的建立从根本上改变了一直以来自由式滑雪空中技巧项目运动员助滑距离完全依靠教练员、运动员凭经验决定,再经反复多次试跳才能最后确定的状态,更适应国际大赛的需要,有利于运动员最佳技术水平的发挥。     

专项速度对女子花样滑冰联合旋转动作的影响分析与强化策略

联合旋转技巧是制约我国花样滑冰女子单人滑项目技术发展的主要因素,以提高我国女子花样滑冰水平为出发点,研究女子花样滑冰专项速度对联合旋转动作的影响。重点通过观测法,对11名青少年女子花样滑冰运动员的联合旋转成绩进行统计,深入剖析助滑速度、角速度和水平速度对联合旋转动作的影响,得出从直线滑行到完成旋转动作,较快的助滑速度、角速度和水平速度分别能在不同阶段提高旋转动作的质量。并提出符合花样滑冰技术特点的专项速度训练方法,帮助运动员更好地完成联合旋转动作,促进我国花样滑冰女子单人滑运动成绩的提高。     

备战盐湖城冬奥会空中技巧国家集训队运动员助滑速度知觉测量与训练的研究

运用实践法配合国家集训队训练，以自报速度与实测速度的差值，评价运动员速度知觉。应用反馈原理，进行速度知觉训练，提高运动员助滑速度知觉能力，使运动员在不同条件下，都能调整在适宜的助滑速度下起跳，解决他们不会测速和测速不准的问题，最终为在盐湖城冬奥会上实现我国雪上项目金牌零的突破做贡献，特进行本课题研究。     

自由式滑雪空中技巧运动员助滑技术的分析

空中技巧运动员的助滑技术对整个动作能否准确完成起着至关重要的作用。通过访谈多次参加FIS举办的空中技巧国际比赛的运动员和教练员,并对空中技巧运动员助滑技术进行观察及分析,认为低姿蹲踞式助滑更有利于在助滑阶段获得与所要跳跃动作相适宜的速度和为起跳做好准备。     

跳台滑雪助滑阶段计算流体动力学模拟及优化

目的：针对跳台滑雪助滑阶段姿态进行计算流体动力学分析,以确定影响出台起跳速度的决定性因素,以此帮助运动员进一步优化助滑动作,减小助滑阶段受到的空气阻力,从而在相同出发格及起跳动作等条件下获得更高的出台起跳速度,为训练和比赛提供有针对性的理论支持。方法：采集我国跳台滑雪集训队男子运动员身体形态数据,基于此建立空气动力学数字孪生模型,并将这一模型投入计算流体动力学分析场景中进行模拟计算,探索最优化的姿态角度区间。数值模拟涉及的姿态角度包括躯干攻角,踝关节角等运动学数据。结果：在一定范围内,运动员及装备组成的多体系统离地面距离越近,运动员在助滑阶段受到的升力越大;运动员在助滑阶段除了保持较小躯干攻角,也可以通过降低躯干高度、髋关节内收角度等方法进一步降低在助滑加速阶段受到的空气阻力;此外,以最大升阻比姿态完成助滑阶段并不能获得最大的出台起跳速度。结论：通过调整助滑姿态能够获得更高出台起跳速度的主要原因是空气阻力的减小,并且系统受到的升力大小较之于重力大小等因素存在数量级差异。因此,相较于增加空气升力,在助滑阶段运动员姿态优化的首要目的应该是减小空气阻力。实践中应该通过调整躯干、肢体姿态对助滑...     

不同级别优秀散打运动员鞭腿技术动作特征及其对击打速度的影响

为探求优秀散打运动员的体重差异与鞭腿技术动作特征是否对击打速度产生影响。方法：运用VICON Nexus 3D运动捕捉系统,对小、中、大三个级别15名运动员运用鞭腿技术动作快速击打目标物时的运动轨迹进行采集。依据鞭打动作特点和下肢关节运动特征,将技术动作划分为四个时刻、三个时段,并对四个时刻下肢关节的角度以及三个时段的动作位移、时间、速度、角速度等运用VICON Polygon分析软件进行计算。结果表明：启动时段（P1）小级别运动员的躯干和支撑腿各关节运动幅度呈"上大下小"状态,大级别运动员呈"上小下大"状态;三个级别运动员作用腿下肢关节的运动方向相同,运动幅度却出现差异,小级别运动员启动时段的动作速度相对较快。击打时段（P2）三个级别运动员支撑腿的髋、踝关节回旋运动方向出现差异;作用腿下肢关节运动方向相同,中级别运动员膝关节屈曲角度相对较大、转动半径相对较小,击打时段的动作速度也相对较快。回收阶段（P3）三个级别运动员支撑腿髋关节屈伸、回旋运动方向出现差异;作用腿下肢关节运动方向相同,小级别运动员作用腿下肢关节转动半径相对较小,回收时段的动作速度也相对较快。不同级别运动员鞭腿技术动作特征对击打速度存在显著性差异,相同级别散打运动员减轻体重、改善下肢关节的运动方向和运动幅度,才是提高击打速度的重要途径。     

我国优秀赛艇运动员专项知觉运动技能概念模型的构建与检验

在前期质性研究的基础上,编制了赛艇运动员专项知觉运动技能问卷,并采用项目分析、探索性因素分析和验证性因素分析等量化研究手段,对该概念模型进行检验。结果显示,赛艇运动员专项运动知觉技能包括自身状态知觉运动技能、艇状态知觉运动技能、桨状态知觉运动技能3个维度;自身状态知觉运动技能包含自身用力知觉和自身体能知觉2个子维度;艇状态知觉运动技能包括艇速知觉运动技能、艇平衡知觉运动技能、艇身状态知觉运动技能和滑座运动状态知觉4个子维度;桨状态知觉运动技能包括划桨效果知觉运动技能、划桨动作调控能力、桨频知觉调控能力和桨力知觉调控能力4个子维度。量化研究检验的赛艇运动员专项运动知觉技能概念模型与前期质化研究结果基本一致,问卷信效度良好,具有一定的理论和实用价值。     

越野滑雪运动员运动性疲劳的恢复

越野滑雪是周期性耐力项目,运动时间多、距离长,能量消耗大,对运动员的心理和机体能力要求较高。越野滑雪运动员的运动训练恢复是运动训练中的重要组成部分,良好的消除疲劳方法,能提高运动水平。结合越野滑雪运动训练实践,运用理论分析方法阐述越野滑雪运动疲劳产生的机理和检测方法,并提出恢复训练、营养补充和心理训练等方法,旨在为促进越野滑雪运动员运动疲劳的积极恢复提供理论依据。     

Fatigue in a simulated cross-country skiing sprint competition

Abstract

The aim of this study was to assess fatigue during a simulated cross-country skiing sprint competition based on skating technique. Sixteen male skiers performed a 30-m maximal skiing speed test and four 850-m heats with roller skies on a tartan track, separated by 20 min recovery between heats. Physiological variables (heart rate, blood lactate concentration, oxygen consumption), skiing velocity, and electromyography (EMG) were recorded at the beginning of the heats and at the end of each 200-m lap during the heats. Maximal skiing velocity and EMG were measured in the speed test before the simulation. No differences were observed in skiing velocity, EMG or metabolic variables between the heats. The end (820–850 m) velocities and sum-iEMG of the triceps brachii and vastus lateralis in the four heats were significantly lower than the skiing velocity and sum-iEMG in the speed test. A significant correlation was observed between mean oxygen consumption and the change in skiing velocity over the four heats. Each single heat induced considerable neuromuscular fatigue, but recovery between the heats was long enough to prevent accumulation of fatigue. The results suggest that the skiers with a high aerobic power were less fatigued throughout the simulation.     

我国大众滑雪指导员的现状与发展

伴随着我国大众高山滑雪运动的异常迅猛的发展,许多始料不及的问题出现在我们面前了,如何解决好诸多问题是引导大众滑雪运动健康发展的关键。其中,滑雪指导员在引导大众滑雪运动持续发展,正确指导滑雪技术,有效地指导安全滑雪及创建和谐、融洽的滑雪者之间人际方面的独特作用不容忽视。     

自由式滑雪空中技巧运动员主要技术和心理控制研究

运用系统控制理论和最优化控制理论，采用实验室和现场实证研究相结合，群体与个体追踪研究相结合，心理指标、运动表现和运动绩效等多指标评定相结合的方法，对我国自由式滑雪空中技巧运动员的主要技术和心理控制进行研究。结果表明，现场监测与反馈训练能有效提高运动员助滑速度知觉的控制能力；多种表象训练可较好地促进运动员空中动作质量的提高；现场技术监控能有效地提高运动员着陆稳定性；多种心理训练方式可以较好地保持良好的赛前心理准备状态，从而保持运动员技术水平正常发挥。这一成果为尖子运动员获得优异成绩提供了科技支撑。同时，也为今后进行类似的研究提供了方法学借鉴。     

Knee angular displacement and extensor muscle activity in telemark skiing and in ski-specific strength exercises

Much of the training of competitive telemark skiers is performed as dry-land exercises. The specificity of these exercises is important for optimizing the training effect. Our aim here was to study the activation of the knee extensor musculature and knee angular displacement during competitive telemark skiing and during dry-land strength training exercises to determine the specificity of the latter. Specificity was analysed with respect to angular amplitude, angular velocity, muscle action and electromyographic (EMG) activity. Five male telemark skiers of national and international standard volunteered to participate in the study, which consisted of two parts: (1) skiing a telemark ski course and (2) specific dry-land strength training exercises for telemark skiing (telemark jumps and barbell squats). The angular displacement of the right knee joint was recorded with an electrogoniometer. A tape pressure sensor was used to measure pressure between the sole of the foot and the bottom of the right ski boot. Electromyographic activity in the right vastus lateralis was recorded with surface electrodes. The EMG activity recorded during maximum countermovement jumps was used to normalize the EMG activity during telemark skiing, telemark jumps and barbell squats. The results showed that knee angular displacement during telemark skiing and dry-land telemark jumps had four distinct phases: a flexion (F1) and extension (E1) phase during the thrust phase of the outside ski/leg in the turn/jump and a flexion (F2) and extension (E2) phase when the leg was on the inside of the turn/jump. The vastus lateralis muscle was activated during F1 and E1 in the thrust phase during telemark skiing and telemark jumps. The overall net knee angular amplitude was significantly greater (P < 0.05) for telemark jumps than for telemark skiing. Barbell squats showed a knee angular amplitude significantly greater than that in telemark skiing (P < 0.05). The mean knee angular velocity of the F1 and E1 phases during telemark skiing was about 0.47 rad x s(-1); during barbell squats, it was about 1.22 rad x s(-1). The angular velocity during telemark jumps was 2.34 and 1.59 rad x s(-1) in the F1 and E1 phase, respectively. The normalized activation level of the EMG bursts during telemark skiing, telemark jumps and barbell squats was 70-80%. In conclusion, the muscle action and level of activation in the vastus lateralis during the F1 and E1 phases were similar during telemark skiing and dry-land exercises. However, the dry-land exercises showed a larger knee extension and flexion amplitude and angular velocity compared with telemark skiing. It appears that an adjustment of knee angular velocity during barbell squats and an adjustment of knee angle amplitude during both telemark jumps and barbell squats will improve specificity during training.     

Combined metabolic gas analyser and dGPS analysis of performance in cross-country skiing

The purpose of this study was to provide a more detailed analysis of performance in cross-country skiing by combining findings from a differential global positioning system (dGPS), metabolic gas measurements, speed in different sections of a ski-course and treadmill threshold data. Ten male skiers participated in a freestyle skiing field test (5.6 km), which was performed with dGPS and metabolic gas measurements. A treadmill running threshold test was also performed and the following parameters were derived: anaerobic threshold, threshold of decompensated metabolic acidosis, respiratory exchange ratio = 1, onset of blood lactate accumulation and peak oxygen uptake (VO2peak). The combined dGPS and metabolic gas measurements made detailed analysis of performance possible. The strongest correlations between the treadmill data and final skiing field test time were for VO2peak (l x min(-1)), respiratory exchange ratio = 1 (l x min(-1)) and onset of blood lactate accumulation (l x min(-1)) (r = -0.644 to - 0.750). However, all treadmill test data displayed stronger associations with speed in different stretches of the course than with final time, which stresses the value of a detailed analysis of performance in cross-country skiing. Mean oxygen uptake (VO2) in a particular stretch in relation to speed in the same stretch displayed its strongest correlation coefficients in most stretches when VO2 was presented in units litres per minute, rather than when VO2 was normalized to body mass (ml x kg(-1) x min(-1) and ml x min(-1) x kg(-2/3)). This suggests that heavy cross-country skiers have an advantage over their lighter counterparts. In one steep uphill stretch, however, VO2 (ml x min(-1) x kg(-2/3)) displayed the strongest association with speed, suggesting that in steep uphill sections light skiers could have an advantage over heavier skiers.     

Biomechanical determinants of cross-country skiing performance: A systematic review

ABSTRACT

Cross-country skiing is a complex endurance sport requiring technical skills, in addition to considerable physiological and tactical abilities. This review aims to identify biomechanical factors that influence the performance of cross-country skiers. Four electronic databases were searched systematically for original articles in peer-reviewed journals addressing the relationship between biomechanical factors (including kinematics, kinetics, and muscle activation) and performance while skiing on snow or roller skiing. Of the 46 articles included, 22 focused exclusively on the classical technique, 18 on the skating technique, and six on both. The indicators of performance were: results from actual or simulated races (9 articles); speed on specific tracts (6 articles); maximal or peak speed (11 articles); skiing economy or efficiency (11 articles); and grouping on the basis of performance or level of skill (12 articles). The main findings were that i) cycle length, most often considered as a major determinant of skiing speed, is also related to skiing economy and level of performance; ii) higher cycle rate related with maximal speed capacity, while self-selected cycle rate improves skiing economy at sub-maximal speeds; iii) cross-country skiing performance appears to be improved by joint, whole-body, ski, and pole kinematics that promote forward propulsion while minimizing unnecessary movement.     

Knee angular displacement and extensor muscle activity in telemark skiing and in ski-specific strength exercises

Much of the training of competitive telemark skiers is performed as dry-land exercises. The specificity of these exercises is important for optimizing the training effect. Our aim here was to study the activation of the knee extensor musculature and knee angular displacement during competitive telemark skiing and during dry-land strength training exercises to determine the specificity of the latter. Specificity was analysed with respect to angular amplitude, angular velocity, muscle action and electromyographic (EMG) activity. Five male telemark skiers of national and international standard volunteered to participate in the study, which consisted of two parts: (1) skiing a telemark ski course and (2) specific dry-land strength training exercises for telemark skiing (telemark jumps and barbell squats). The angular displacement of the right knee joint was recorded with an electrogoniometer. A tape pressure sensor was used to measure pressure between the sole of the foot and the bottom of the right ski boot. Electromyographic activity in the right vastus lateralis was recorded with surface electrodes. The EMG activity recorded during maximum countermovement jumps was used to normalize the EMG activity during telemark skiing, telemark jumps and barbell squats. The results showed that knee angular displacement during telemark skiing and dry-land telemark jumps had four distinct phases: a flexion (F1) and extension (E1) phase during the thrust phase of the outside ski/leg in the turn/jump and a flexion (F2) and extension (E2) phase when the leg was on the inside of the turn/jump. The vastus lateralis muscle was activated during F1 and E1 in the thrust phase during telemark skiing and telemark jumps. The overall net knee angular amplitude was significantly greater (P<0.05) for telemark jumps than for telemark skiing. Barbell squats showed a knee angular amplitude significantly greater than that in telemark skiing (P<0.05). The mean knee angular velocity of the F1 and E1 phases during telemark skiing was about 0.47 rad?·?s^?1; during barbell squats, it was about 1.22 rad?·?s^?1. The angular velocity during telemark jumps was 2.34 and 1.59 rad?·?s^?1 in the F1 and E1 phase, respectively. The normalized activation level of the EMG bursts during telemark skiing, telemark jumps and barbell squats was 70–80%. In conclusion, the muscle action and level of activation in the vastus lateralis during the F1 and E1 phases were similar during telemark skiing and dry-land exercises. However, the dry-land exercises showed a larger knee extension and flexion amplitude and angular velocity compared with telemark skiing. It appears that an adjustment of knee angular velocity during barbell squats and an adjustment of knee angle amplitude during both telemark jumps and barbell squats will improve specificity during training.