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1.
Control of locomotion in expert gymnasts in the absence of vision   总被引：1，自引：0，他引：1  
The main aim of this study was to determine how gymnasts are affected by the removal of vision when executing simple moves. A secondary aim was to establish whether crucial sensory cues exist for blindfolded gymnasts. Eight expert gymnasts were asked to maintain a straight displacement during three types of blindfolded locomotion: walking, steering a wheelchair and verbally ordering a second person pushing their wheelchair. In the first two conditions, active displacement made proprioceptive cues available to update the body trajectory. In the last condition, however, proprioceptive cues were greatly reduced, since the gymnasts displaced passively. The performance of the gymnasts was compared to that of eight experts in other non-gymnastic sports (control group). The results showed that the participants veered in all conditions. However, except in the verbal condition, the gymnasts departed less from linearity than the controls. We conclude that: (1) even for a simple motor task, gymnasts' performance is altered by eliminating vision; (2) compared with other sportsmen and women, gymnasts are better able to deal with the absence of vision when proprioceptive cues are available. These findings suggest two possible explanations: (1) gymnasts are more able to 'pick up' crucial information and (2) a gymnast's proprioceptive system is more sensitive.  相似文献   

2.
Abstract

The aim of this study was to increase our understanding of postural regulation by analysing an arbitrary posture – the handstand. We assessed the relative influence of peripheral vision and central visual anchoring on the postural balance of gymnasts in the inverted-stand posture. Displacements of the centre of pressure, the angles between the body segments, and the gymnast's height in the handstand were analysed. Postural regulation in the handstand appeared to be organized according to a system similar to that in erect posture, with three articular levels suggesting the existence of a typical organization of human posture. Moreover, both intra-modal (central and peripheral vision) and inter-modal sensory systems (vision and other balance systems) contributed to the postural regulation. The results are interpreted in terms of an ecological approach to posture in which postural regulation can be considered as an emergent phenomenon.  相似文献   

3.
This study aimed at supporting the specificity of learning hypothesis, when aiming was based on internal cues, as directing the hand toward a "self-defined" target location. Participants practiced modest (20 trials) or intensive (720 trials) training with visual and proprioceptive information or proprioceptive information only. Pretests and posttests were performed in sensory conditions that did or did not match the training condition. Results showed that dynamic visual cues played a dominant role at the beginning of the task, and an intensive practice resulted in increased accuracy of kinesthetic information and efferent mechanisms of motor responses. These results have implications with regard to motor learning conceptions and training as a function of the task constraints.  相似文献   

4.
Abstract

This study aimed at supporting the specificity of learning hypothesis, when aiming was based on internal cues, as directing the hand toward a “self-defined” target location. Participants practiced modest (20 trials) or intensive (720 trials) training with visual and proprioceptive information or proprioceptive information only. Pretests and posttests were performed in sensory conditions that did or did not match the training condition. Results showed that dynamic visual cues played a dominant role at the beginning of the task, and an intensive practice resulted in increased accuracy of kinesthetic information and efferent mechanisms of motor responses. These results have implications with regard to motor learning conceptions and training as a function of the task constraints.  相似文献   

5.
The aim of this study was to determine the range of movement in gymnastic and dance populations. Sixty-five participants (41 females, 24 males; mean age 21.4 years) were assessed. The sample included dancers and gymnasts ranging from novice and club standard to international and professional status. Non-specialized physical education students acted as controls. Range of movement was measured at the shoulders, hips, lumbar spine and ankles using a Loebl hydrogoniometer, and inherent joint laxity was assessed using Beighton and coworkers' adaptation of the Carter and Wilkinson 9-point scale. The right and left sides of the body were assessed and measures of active and passive motion were recorded. A graded increase in laxity was observed from controls, through novice gymnasts, to dancers and finally international gymnasts. The greater laxity of females than males was also confirmed. Dancers and gymnasts had a greater passive range of movement in all joints, which was partly inherited and partly acquired. There was a large difference between their active and passive ranges, which appeared to render the joints unstable.  相似文献   

6.
Research examining our ability to avoid obstacles in our path has stressed the importance of visual input. The aim of this study was to determine if athletes playing varsity-level field sports, who rely on visual input to guide motor behaviour, are more able to guide their foot over obstacles compared to recreational individuals. While wearing kinematic markers, eight varsity athletes and eight age-matched controls (aged 18–25) walked along a walkway and stepped over stationary obstacles (180° motion arc). Visual input was manipulated using PLATO visual goggles three or two steps pre-obstacle crossing and compared to trials where vision was given throughout. A main effect between groups for peak trail toe elevation was shown with greater values generated by the controls for all crossing conditions during full vision trials only. This may be interpreted as athletes not perceiving this obstacle as an increased threat to their postural stability. Collectively, findings suggest the athletic group is able to transfer their abilities to non-specific conditions during full vision trials; however, varsity-level athletes were equally reliant on visual cues for these visually guided stepping tasks as their performance was similar to the controls when vision is removed.  相似文献   

7.
我国优秀艺术体操运动员月经状况与骨矿含量的研究   总被引：5，自引：1，他引：4  
选取国内优秀艺术体操运动员20名,年龄为15～19岁,训练年限1～10年,其中健将13人(有一人16岁尚未月经初潮)。对她们进行了月经状况的调查和骨密度的测量。结果显示,优秀艺术体操运动员存在严重的月经失调问题:19人中有16人月经不调,月经不调的发生率达84.2％。这些优秀艺术体操运动员的骨密度较低,甚至低于一般人,没能显示出体育运动对骨骼发育的良好促进作用,这是与月经不调相联系的。进一步的分析表明,月经不定期、闭经及痛经的运动员骨密度明显低于月经正常的运动员。  相似文献   

8.
Acrobatic gymnasts need excellent balance control to execute pyramids where one gymnast is supported by another. The objectives of this study were: (1) to describe balance performance by assessing the centre of pressure displacement in a group of acrobatic gymnasts executing pyramids; (2) to determine the relationship between the parameters describing the centre of pressure oscillations and pyramid score; and (3) to examine the role of each foot in providing a solid base of support to maintain the balance of the pyramid. Sixteen acrobatic gymnasts grouped in pairs performed a Half pyramid and a Straddle pyramid held for 7 s on two force platforms. Path length, variance, range trajectory, and surface area of the centre of pressure of each foot were examined to analyse the balance of the pyramid. The path length was correlated with the pyramid score (Straddle: p = 0.692 [large]; Half: p = 0.407 [moderate]). There were differences in the functions of each leg to maintain balance, with the non-preferred leg supporting a higher weight of the pyramid while the preferred leg performed control movements to maintain balance. The results suggested that quantitative analysis of balance can provide important information on pyramid performance.  相似文献   

9.
Visual and postural control of an arbitrary posture: the handstand   总被引：1，自引：0，他引：1  
The aim of this study was to increase our understanding of postural regulation by analysing an arbitrary posture - the handstand. We assessed the relative influence of peripheral vision and central visual anchoring on the postural balance of gymnasts in the inverted-stand posture. Displacements of the centre of pressure, the angles between the body segments, and the gymnast's height in the handstand were analysed. Postural regulation in the handstand appeared to be organized according to a system similar to that in erect posture, with three articular levels suggesting the existence of a typical organization of human posture. Moreover, both intra-modal (central and peripheral vision) and inter-modal sensory systems (vision and other balance systems) contributed to the postural regulation. The results are interpreted in terms of an ecological approach to posture in which postural regulation can be considered as an emergent phenomenon.  相似文献   

10.
徐凤萍 《体育科研》2010,31(5):76-78
运用艺术体操圈器械对不同训练程度者及不同级别的运动员进行测试,发现有训练者与无训练者之间的抛接控制能力有着明显的差异;不同训练水平的运动员对于抛接控制能力也具有一定的差异性,训练水平越高,准确性越高;本体感觉能力具有个体差异性,其既受后天运动训练的影响作用,也受到个人先天因素的作用制约;艺术体操运动员上肢本体感觉能力的强弱,可以作为艺术体操运动员的选材与能力评定的参考指标。为今后选拔和训练艺术体操运动员提供科学准确的参考依据。  相似文献   

11.
The purpose of this study was to examine whether any differences exist in the cognitive and behavioural strategies of gymnasts competing at different elite levels. Thirty-eight male gymnasts competing at different competitive levels in an Australian gymnastic championship completed a standardized questionnaire prior to the first day of the competition. The questionnaire focused on a number of psychological factors that may affect both training and competition. Using both t-tests and simple discriminant function analysis, it was revealed that gymnasts competing at different elite levels could be distinguished on the basis of two psychological factors, psychological recovery and self-confidence, as well as the behavioural measure, training hours. Specifically, gymnasts competing at higher elite levels versus those at lower elite levels, were better able to recover from their competitive mistakes, were more confident and trained longer per week.  相似文献   

12.
Shock absorption and stability during landings is provided by both, gymnast ability and mat properties. The aims of this study were to determine the influence of different mat constructions on their energy absorption and stability capabilities, and to analyse how these properties affect gymnast's plantar pressures as well as subjective mat perception during landing. Six mats were tested using a standard mechanical drop test. In addition, plantar pressures and subjective perception during landing were obtained from 15 expert gymnasts. The different mats influenced plantar pressures and gymnasts' subjective perception during landing of gymnasts. Significant correlations between plantar pressures at the medial metatarsal and lateral metatarsal zones of the gymnasts' feet with the different shock absorption characteristics of the mats were found. However, subjective perception tests were not able to discriminate mat functionality between the six mats as no significant correlations between the mechanical mat properties with the subjective perception of these properties were found. This study demonstrated that plantar pressures are a useful tool for discriminating different landing mats. Using similar approaches, ideally including kinematics as well, could help us in our understanding about the influences of different mats upon gymnast-mat interaction.  相似文献   

13.
The aim of this study was to examine female gymnasts' fear of injury, their sources of self-efficacy and the psychological strategies used to overcome their fears. The participants were 10 female gymnasts aged 12?–?17 years. They had all taken part in competitive gymnastics and had experienced some type of injury during their careers. Individual interviews were conducted using a structured interview guide. Data were analysed using an inductive content analysis. The results indicated that gymnasts were most fearful of injuries because of the difficulty in returning from an injury and being unable to participate in practices and competitions while injured. Gymnasts described aspects of their past performance experience, such as success, consistency and communication with significant others, as important sources of self-efficacy. Some examples of psychological strategies used to overcome their fear of injury were mental preparation (e.g. imagery, relaxation), just “going for a skill” and the coaches' influence.  相似文献   

14.
The functional classification system for wheelchair basketball is based on an analysis of the players' functional resources through field-testing and game observation. Under this system, players are assigned a score of 1 to 4.5. The aim of this study was to determine if the wheelchair basketball player classification system reflects the existing differences in performance of elite female players. During the World Championship for Wheelchair Basketball in Sydney 1998, eight teams were videotaped for three 40-min games for a total of 120?min per team. Fifty-nine female players (Class I [1 and 1.5 points] n?=?12; Class II [2 and 2.5 points] n?=?20; Class III [3 and 3.5 points] n?=?13; Class IV [4 and 4.5 points] n?=?14) were retained for a detailed performance analysis by means of the Comprehensive Basketball Grading System (CBGS). Two-way analysis of variance showed high point players to perform better compared with low point players for the majority of variables determining the quality of game performance. A lack of significant differences between two adjacent classes was explained on the basis of the methodological approach, the class–position relationship in this sample, and the performance level of women's wheelchair basketball. We conclude that the performance of elite female wheelchair basketball players is dependent on functional ability.  相似文献   

15.
Gymnastics talent identification focuses on the identification of young gymnasts who display characteristics for potential success in the future. The aim of this study was to identify which current performance characteristics are related to performance in competition 2 years later. Twenty-three female gymnasts aged 7-8 years completed a multidimensional test battery measuring anthropometric, physical, and coordinative characteristics and were technically evaluated by expert coaches. Two years later, the all-around competition results of those gymnasts now participating in elite (n = 12) and sub-elite (n = 11) competition were obtained. None of the initial measurements significantly correlated with the results of the sub-elite gymnasts 2 years later. For the elite gymnasts, a non-sport-specific motor test battery correlated strongly with the competition result, with more than 40% of the variation in competition performance being explained by the result on that test 2 years earlier. Neither the coaches' judgement nor the anthropometric and physical characteristics were sensitive enough to predict performance. A motor coordination test might be valuable in the early identification of gymnasts, as its discriminative and predictive qualities might be sufficiently powerful for selection within a relatively homogeneous population of gymnasts exhibiting similar anthropometric and physical profiles.  相似文献   

16.
The purpose of this study was to examine whether any differences exist in the cognitive and behavioural strategies of gymnasts competing at different elite levels. Thirty‐eight male gymnasts competing at different competitive levels in an Australian gymnastic championship completed a standardized questionnaire prior to the first day of the competition. The questionnaire focused on a number of psychological factors that may affect both training and competition. Using both t‐tests and simple discriminant function analysis, it was revealed that gymnasts competing at different elite levels could be distinguished on the basis of two psychological factors, psychological recovery and self‐confidence, as well as the behavioural measure, training hours. Specifically, gymnasts competing at higher elite levels versus those at lower elite levels, were better able to recover from their competitive mistakes, were more confident and trained longer per week.  相似文献   

17.
It is acknowledged that knowledge and knowledge bases are an important part of coach and athlete learning and that the coach – athlete relationship is crucial to knowledge created, shared and used. This said knowledge about nutrition as constructed by elite gymnasts would seem particularly important in a culture long associated with weight control practices and disordered eating. This paper provides an insight into the ways that 10 Brazilian Olympic gymnasts construct ideas pertaining to nutritional knowledge across generational periods (between 1980 and 2004) where significant organisational change in Women’s Artistic Gymnastics in Brazil occurred and included the introduction of dieticians. Drawing upon different knowledge types and paying attention to the coaching context, the life histories of 10 Olympic gymnasts were used to open a window on knowledge construction pertaining to nutrition by three generations of gymnasts. The findings draw attention to two main illustrative themes. Firstly, coaches’ personal knowledge, whilst perceived as incomplete by gymnasts, reinforced a narrative of weight loss for gymnasts regardless of generation. Secondly, the younger generations of gymnasts perceived that the introduction of dieticians into structured provision enabled them to use better structured knowledge, and with it a sense of increased autonomy and corporeal learning via the construction of tacit embodied knowledge leading to healthier practices. Reflections are given to the role of the coach, dieticians and pedagogical actions, and the continued reshaping of knowledge in elite gymnastics.  相似文献   

18.
Asymmetry in gymnastics underpins successful performance and may also have implications as an injury mechanism; therefore, understanding of this concept could be useful for coaches and clinicians. The aim of this study was to examine kinematic and external kinetic asymmetry of the arm segments during the contact phase of a fundamental skill, the forward handspring on floor. Using a repeated single subject design six female National elite gymnasts (age: 19?±?1.5 years, mass: 58.64?±?3.72?kg, height: 1.62?±?0.41?m), each performed 15 forward handsprings, synchronised 3D kinematic and kinetic data were collected. Asymmetry between the lead and non-lead side arms was quantified during each trial. Significant kinetic asymmetry was observed for all gymnasts (p?相似文献   

19.
In most Paralympic wheelchair sports, active trunk range of movement is assessed by observing shoulder girdle excursion during active trunk movements and is a key determinant of an athlete's class. However, to date research evaluating the impact of reduced trunk range of movement on wheelchair sports performance has not been conducted. In the present study, 15 non-disabled male participants performed two 20-s sprints on a wheelchair ergometer in each of three seating positions. Positions were typical of those used to enhance sitting stability in wheelchair sport and each impacted available trunk range of movement differently: condition-90 (seated with thighs horizontal; unrestricted range of movement) condition-45 (seated with thighs in 45°), and condition-0 (seated with hips maximally flexed; minimum range of movement). In condition-90, the trunk only actively contributed to the first push; for the remainder of the sprint, the trunk was held almost isometrically at 48.2° to the horizontal (range 42.1-56.4°). Similar patterns were observed for both condition-45 and condition-0. Compared with condition-90, participants in condition-0 had reduced capacity to accelerate of statistical (P < 0.05) and practical significance. These findings are an important initial step towards evidence-based decision making in classification. Future research should evaluate the individual and collective impact of other factors that affect the trunk's contribution to wheelchair sports performance, including strapping, seating position, and impairments of trunk muscle power and coordination.  相似文献   

20.
The aim of the study was to determine if sex differences exist in the key elbow and wrist joint injury risk factors during different cartwheel (CW) and round-off (RO) techniques performed by young male and female artistic gymnasts. Sixteen active young gymnasts (8 males and 8 females) performed 30 successful trials of CW and RO with three different hand positions (parallel (10), T-shape (10) and reverse (10)). Synchronised kinematic and kinetic data were collected for each trial. Two-way repeated measures ANOVA (3 × 2, technique × sex) and effect-sizes (ES) were used for statistical analysis. In conclusion, female gymnasts exhibited greater normalised peak vertical ground reaction forces (VGRF), elbow and wrist compression forces and elbow internal adduction moments during CW and RO skills compared with male gymnasts. In both sexes, the parallel and reverse techniques increased peak VGRF, elbow and wrist compression forces and the elbow internal adduction moment. Increased elbow flexion resulted in decreased peak VGRF, elbow compression forces and elbow internal adduction moment. Injury risk factors including elbow extension and internal adduction moment with axial compression force suggest that a CW and RO in reverse and parallel techniques can be hazardous especially for young female gymnasts.  相似文献   

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