The locus of focus: The effect of switching from a preferred to a non-preferred focus of attention

Abstract

Focusing strategies are known to play a significant role in motor performance, with individuals who use an internal focus on body movement typically showing poorer outcomes than those who focus on features of the external environment. Focus of attention and switching of one's focus are examined in the context of two different complex motor skills along with a factor not previously examined systematically, individual preference. In both experiments, participants were introduced to focusing strategies that might be employed when attempting a sensorimotor task. Explanations of both strategies were given to participants. Specifically, for an internal focus, participants were instructed to concentrate on their body movements, while for an external focus, they were instructed to focus on aspects in the environment. They were then asked which strategy they preferred. Participants then continued either with their preferred focus or were instructed to switch to their non-preferred focus. The advantage that the external focus typically enjoys turns out not to be a simple one and interacts with individual preference and with the “forced-opposite” manipulation. Our results support the growing consensus that encouraging individuals to adopt an internal focusing strategy is counterproductive in complex sensorimotor tasks. They also suggest that individual preferences play a role.     

Effects of distinct practice conditions on the learning of the o soto gari throwing technique of judo

The aim of this study was to investigate the effects of different types of practice on learning the o soto gari, focusing on the kuzushi (unbalancing the opponent). A total of 64 children (mean age 9.19 ± 1.41 years) were assigned to one of four groups: (1) static traditional practice, i.e., uchikomi – repetition of the moving pattern that characterises the technique up to the point of throwing; (2) in motion traditional practice – uchikomi with the tori (player executing the technique) moving/walking; (3) whole practice with pre-kuzushi – full technique with a preparatory component for kuzushi; (4) progressive parts practice with pre-kuzushi – progressively introducing kuzushi, tsukuri (set-up to execute the technique) and kake (final part of the technique; projection) with pre-kuzushi. Pre-test, acquisition, post-test and retention test were carried out. Movements were video recorded and analysed regarding three aspects: global technique of the tori, occurrence of a movement pattern performed by the tori to unbalance the uke (player receiving the “attack”), and occurrence of actual unbalance (kuzushi). Results showed no significant differences between-groups. However, different within-groups improvements suggest that using a uchikomi with pre-kuzushi can help learners deal with the motor actions of pulling and pushing in order to unbalance the opponent.     

Impulsive force on the head during performance of typical ukemi techniques following different judo throws

In this study, eight judo athletes who are major candidates for the Japan national team were recruited as participants. Kinematic analysis of exemplary ukemi techniques was carried out using two throws, o-soto-gari, a throw linked to frequent injury, and o-uchi-gari. The aim of this study was to kinematically quantify the timing patterns of exemplary ukemi techniques and to obtain kinematic information of the head, in a sequence of ukemi from the onset of the throw to the completion of ukemi. The results indicated that the vertical velocity with which the uke’s head decelerated was reduced by increasing the body surface exposed to the collision with the tatami and by increasing the elapsed time. In particular, overall upper limb contact with the tatami is greatly associated with deceleration. In o-soto-gari, the impulsive force on the faller’s head as the head reached the lowest point was 204.82 ± 19.95 kg m · s^–2 while in o-uchi-gari it was 118.46 ± 63.62 kg m · s^–2, z = ?1.75, P = 0.08, and it did present a large-sized effect with r = 0.78. These findings indicate that the exemplary o-soto-gari as compared to o-uchi-gari is the technique that causes more significant damage to the uke’s head.     

Kinematic comparison of the seoi-nage judo technique between elite and college athletes

This study sought to identify biomechanical factors that determine fast and skilful execution of the seoi-nage (shoulder throw) technique by comparing kinematics between elite and college judo athletes. Three-dimensional motion data were captured using a VICON-MX system with 18 cameras operating at 250 Hz as three male elite and seven male college judo athletes performed seoi-nage. No significant difference was found in motion phase time of the turning phase between the two groups, indicating that motion phase time is not necessarily a factor contributing quickness in seoi-nage. The maximum relative velocity of the whole body centre of mass along the anterior–posterior direction was significantly greater in the elite athletes (2.74 ± 0.33 m/s) than in the college athletes (1.62 ± 0.47 m/s) during the turning phase (p = 0.023). The overall angular velocity of the body part lines, particularly the arm line, tended to be greater in the elite athletes (p = 0.068). The results imply that the velocity of the thrower relative to the opponent in the forward drive and turning motion reflects high skill seoi-nage. Coaches should recognise the relative forward velocity as a factor that may contribute to a successful seoi-nage when teaching the judo throw technique.     

Home advantage in judo: A study of the world ranking list

Abstract

In 2009, the International Judo Federation established a ranking system (RS) to classify athletes and to distribute the competitor quotas of the Olympic Games. However, the RS does not consider the home advantage. This issue has not been studied in judo, and its implications for the RS have not been determined. The objective was to verify the home advantage in judo in terms of winning a medal or the number of matches won. Therefore, 25 competitions that computed points for the RS in 2009 were analysed. Logistic regression analysis and the Poisson generalised linear model were used for the analyses, which included the relative quality of the athletes. The sample was composed only of athletes who had competed both at home and away. The odds ratio for winning medals was higher for athletes who competed at home for both males and females. The association between the number of matches won and competing at home was significant only for the male athletes. The home advantage was observed in the competitions that used the judo RS. Thus, it is likely that athletes from countries that host competitions using the RS have an advantage in terms of obtaining their Olympic classification.     

Judges in judo conform to the referee because of the reactive feedback system

Abstract

This experiment tested whether the conformism observed among panels of judges in aesthetic sports also occurs among judges in judo. Similar to aesthetic sports, judo judging relies upon a form of open feedback. However, in judo, this system is reactive (i.e. two judges have to publicly ‘correct’ the score given by the higher-status referee), whereas it is active in aesthetic sports (i.e. judges with equal status report their score simultaneously and can use the feedback about the scores of their colleagues for evaluating later performances). In order to test whether such reactive open-feedback system leads to conformism among judges in judo, we designed an experiment in which this feedback was manipulated. Participants were 20 certified Flemish judges, who had to score two sets of 11 ambiguous video sequences that are used during formation and training of judo judges: one set with feedback about the referee's score and one set without feedback. The results revealed that when participants knew the referee's score, their scores were significantly more in line with this score than when they did not know this score. More specifically, for both sets of sequences at least 10% less deviations from the referee were observed when participants were given feedback about the score of the referee. These results suggest that preventable conformism can occur in typical judo judging, that is with reactive open feedback.     

对我国少年男子柔道技术现状的调查与分析

对我国少年男子柔道运动员的技术情况进行了调查，结果表明，当前少年男子柔道以投技得分为主，投、寝技术发展不平衡，对于不同方向的技术和技术组合缺乏训练，体能的总体水平不高，运用规则的能力有待于提高。     

The influence of live- vs. video-model presentation on the early acquisition of a new complex coordination

Background: Demonstration is a widely used method in sports teaching and coaching, based on the assumption that it is more beneficial than verbal instructions or trial-and-error methods for skill acquisition. Although in teaching/coaching situations, the demonstration is usually carried out in front of the learners, in a research context, it is most often presented via a video. However, a direct comparison between these two types of model has rarely been undertaken in a motor context.

Purpose: In this study, we aimed to compare the effectiveness of the observation of a live and a videomodel for the early acquisition of a complex judo movement.

Research Design: Participants observed either a live or a videomodel executing the task. After observation, they practised for three minutes taking five trials and then performed it for analysis. This procedure was repeated three times. The form and technique of each participant's execution were evaluated using a technical score.

Main results: The results indicated a significant improvement in the task execution by the end of the practice session. However, this improvement occurred only for the video-model group between the second and third blocks of practice.

Conclusions: The video demonstration seems more effective than the live one for the early acquisition of a completely new complex coordination. This may be due to the simplification of the visual information in the former condition because of its two-dimensionality. This simplification may allow the observer to identify the more key elements that would guide him/her for the subsequent performance of the task.     

我国青少年女子柔道运动员身体素质测试指标及评价标准的研究

运用问卷调查法、主成分分析法及因子分析法,筛选出具有代表性的、能够反映出柔道运动项目特点的身体素质的指标,在此基础上建立了我国青少年女子柔道运动员身体素质测试指标结构的评价模型,并制订了身体素质发展水平的评价标准,为女子柔道运动员专项运动素质训练的科学化,以及从素质方面进行运动员选材提供参考。     

运动协调的定量方法以及在专项技术分析领域的研究进展

人体的运动协调问题一直受到多个研究领域的关注。Bernstein运动协调观与运动协调的动态系统理论被广泛应用于解释运动协调的形成、发展、特征中,成为研究运动协调的主要理论基础。依据这些理论基础,针对不同类型研究的需要,设计了多种运动协调的定量方法来客观展现人体的协调运动,这些方法都具有各自的优缺点。目前,在专项技术分析领域中,对专项技术中肢体协调层面的研究较多,在多种专项技术中都发现了一些高效的运动协调方式。尽管这些运动协调方式各有不同,但是展现出一些共性的特征。此外,在优秀运动员的技术中,具有较大的肢体协调变异性,这些变异性是肌肉-骨骼复杂系统灵活性的体现,有利于运动任务的实现。在关节动力学、肌肉活动等层面中运动协调的研究相对较少。专项技术中运动协调的研究趋势有:1)由于运动技术种类繁多,各自特征不同,对运动协调的研究将会涉及到更多的运动项目中;2)应用动态系统理论,进一步探索优秀运动员技术中运动协调变异性对专项技术的作用;3)应用动态系统理论,拓展对专项技术中运动协调控制变量的研究;4)拓展在优秀运动员专项技术中关节动力学、肌肉活动等更深层面中运动协调特征的研究。     

Mental fatigue alters the speed and the accuracy of the ball in table tennis

ABSTRACT

This study aimed at evaluating the effects of mental and muscle fatigue on table tennis performance. Mental fatigue (MF) was induced by completion of 90 minutes of the AX-CPT; muscle fatigue was induced by completion of an eccentric exercise performed with the elbow flexors (biceps fatigue, BF) or the knee extensors (quadriceps fatigue, QF). The control condition consisted of watching a movie. Stroke parameters (speed and accuracy of the ball), as well as feelings of fatigue and force production capacity of the elbow flexors (BF, MF and control conditions) and knee extensors (QF condition), were assessed pre and post fatigue protocols. Feelings of fatigue increased post fatigue protocols. Force production capacity decreased only in the BF and QF conditions. BF and MF induced a decrease in accuracy. This decrease in accuracy was associated with an increased ball speed in the BF condition, and a decreased ball speed in the MF condition. QF had a negligible effect on stroke performance. Our results suggest that both mental fatigue, and muscle fatigue, significantly impair table tennis performance and therefore coaches should take into account both the physical and mental state of table tennis players to optimize performance.     

Effect of Information Load and Time on Observational Learning

We examined whether altering the amount of and moment when visual information is presented affected observational learning for participants practicing a bowling skill. On Day 1, four groups practiced a cricket bowling action. Three groups viewed a full-body point-light model, the model's bowling arm, or between-limb coordination of the model's left and right wrists only. Following retention tests on Day 2, all participants practiced after viewing a full-body display. Retention was again tested on Day 3. Bowling accuracy improved in all four practice groups. Kinematics of the bowling arm became more like the model for the full-body and intralimb groups only. All groups improved on measures of interlimb coordination. Visual search data indicated that participants mainly focused their gaze on the model's bowling arm. These data lead to the suggestion that viewing “end-effector” information (i.e., information pertaining to the bowling arm) is an important perceptual constraint early in observational learning. Implicit manipulations designed to increase attention to other sources of information did not facilitate the learning process.     

Coach ratings of skills and their relations to practice,play and successful transitions from youth-elite to adult-professional status in soccer

Elite soccer players (~15 yr) from professional academies in the UK were rated on technical, tactical, physical and creative skills by coaches at time 1 (T1). Players estimated accumulated hours in soccer practice (coach-led activities) and play (self-led activities) during childhood. Coach-ratings were again collected 2.5 yr later (T2) for players that received a professional contract (~17 yr). Adult-professional status was determined at T3 (~ 20 yr). Skill ratings distinguished across the three “future” groups (academy-only, youth-professional only and adult-professional), for all but creative skill. For players that transitioned to youth-professional, medium sized correlations were noted between childhood practice amounts and technical and creative skill ratings at T1, although practice amounts correlated more strongly with skill ratings at T2. Play amounts were not related to any skills. Within groups of youth elite athletes, domain-specific play in childhood, and to a lesser degree practice, were generally not good discriminators of specific-skills. The effects of sport-specific practice on the development (and discriminability) of skills takes time to emerge. We consider the implications for talent development models and purported links between play and creativity.     

Definition and model of life skills transfer

For a sport skill to be considered a life skill, it must be successfully transferred and applied beyond sport. Life skills transfer is an essential process, but it has yet to be fully delineated within the sport psychology literature. The purpose of the current paper is to present a definition and model of life skills transfer and outline future research needs. A critical review of the literature within sport psychology and other learning-based disciplines is offered to assess our current understanding of learning transfer. A definition and model of transfer are then presented, focusing on the athlete learner’s experience of life skills transfer. Within the model, we first examine how athletes bring personal assets and autobiographical experiences to sport. Second, we explore how sport is a learning environment with distinctive demands, programme designs, and coach characteristics and strategies. Third, we explain how transfer contexts provide environmental conditions, which, depending on how they are interpreted or experienced, can help or hinder the transfer of life skills. Ultimately, we postulate that an individual experiences life skills transfer as an ongoing process whereby he/she continually interacts and interprets his/her environments to produce positive or negative life skills transfer outcomes.     

Constraints on dynamic stability during forward,backward and lateral locomotion in skilled football players

The aim of this study was to investigate effects of speed and plane of motion on stability during locomotion in skilled football players. Ten male national-level football players participated in this study to run forward, backward and in lateral directions on a treadmill at 80%, 100% and 120% of their preferred running speeds. The coordinate data of passive reflective markers attached to body segments were recorded using motion capture systems. Time series data obtained from the ankle marker were used for further analyses. The largest finite-time Lyapunov exponent and maximum Floquet multiplier were adopted to quantify local and orbital dynamic stabilities, respectively. Results showed that speed did not significantly change local and orbital dynamic stabilities in any of running patterns. However, both local and orbital dynamic stability were significantly higher in the secondary plane of progression. Data revealed that in running, unlike walking, stability in the direction perpendicular to the direction of running is significantly higher, implying that less active control is required in the secondary plane of progression. The results of this study could be useful in sports training and rehabilitation programmes where development of fundamental exercise programmes that challenge both speed and the ability to maintain stability might produce a tangible enhancement of athletic skill level.     

运动技能获得中内隐认知与外显认知的相互作用研究进展

5外显认知与内隐认知是运动技能认知的两种模式.外显认知是指一种是有日的、受意识控制的、需要付出意志努力并采取一定策略来获取知识的过程,是人们学习运动技能的主要认知模式.内隐认知是指无意识认知.它包括内隐记忆、内隐学习及内隐知觉等认知范式.在运动技能的外显认知中,当指导者提供的外显指导具体且准确,与学习者所要探寻的规则一致时,将促进运动技能的形成,否则将起到阻碍作用.复杂运动技能的学习更适合于两种认知模式的协同化,即先内隐认知后冉外显认知可以使技能学习效果达到最好.     

学龄儿童基本动作技能测量工具AST应用的理论与实证研究

目的旨在研究学龄儿童基本动作技能测试工具AST在国内使用的理论基础与可行性,通过测试技术操作和数据分析实证该测量工具的可信度、有效性与经济性。方法通过实验测试、数理统计等方法验证AST和KTK测量工具的信效度,通过转换后的大肌肉动作协调能力商数(KTKMQ)校标基本动作技能AST测试的同时效度和区别效度。结果受试儿童年龄为7~12岁,平均在(44±11) s的时间完成了AST-1全程测试,在(45±12) s的时间完成了AST-2全程测试;AST-1测试成绩与KTKMQ的相关系数r=0.474(P<0.01),而AST-2测试成绩与KTKMQ呈现中度相关系数r=0.502(P<0.01);除7岁年龄组的AST-2测试与KTKMQ相关性较低外,其他年龄组的相关性均较高(r=0.469和r=0.767)。结论小学学段的体育教学环境中AST测试工具可以快速、便捷、有效的评估儿童的基本动作技能;运动技能轨道AST测量工具在本次研究中表现出较强的测试适宜性,具有重测信度;各年龄组测量结果的区分度和测试项目的鉴别力验证了测量工具的同时效度和区别效度。     

录像示范和现场示范对运动技能观察学习的影响

目的:探讨录像示范和现场示范对运动技能观察学习的影响.办法:48名受试随机分为练习组、现场示范观察组、录像示范观察组和控制组.采用计算机追踪任务,以RMSE为评价指标,对4组受试分别进行10 min后保持测试、24 h后保持测试和迁移测试.结果显示:在所有测试中,录像示范观察组和现场示范组受试操作绩效没有显著性差异;在10 min后保持测试和24 h后保持测试中,练习组受试操作绩效显著好于其他组受试,现场示范观察组和录像示范观察组受试操作绩效显著好于控制组;在迁移测试中,练习组、录像示范观察组、现场示范观察组受试操作绩效没有显著性差异,但都显著好于控制组.