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Coral Falco Javier Molina-García Octavio Álvarez Isaac Estevan 《Sports biomechanics / International Society of Biomechanics in Sports》2013,12(4):381-382
The aim of this study was to investigate the effects of target distance on temporal and impact force parameters that are important performance factors in taekwondo kicks. Forty-nine taekwondo athletes (age = 24.5 ± 5.9 years; mass = 79.9 ± 10.8 kg) were recruited: 13 male experts, 21 male novices, 8 female experts, and 6 female novices. Impact force, reaction time, and execution time were computed. Three-way repeated measure ANOVAs revealed significant ‘distance’ effect on impact force, reaction time, and execution time (p = 0.001). Comparisons between distance conditions revealed that taekwondo athletes kicked with higher impact force from short distance (17.6 ± 7.5 N/kg) than from long distance (13.1 ± 5.7 N/kg) (p < 0.001), had lower reaction time from short distance (498 ± 90 ms) and normal distance (521 ± 111 ms) than from long distance (602 ± 121 ms) (p < 0.001), and had lower execution time from short distance (261 ± 69 ms/m) than from normal distance (306 ± 105 ms/m) or from long distance (350 ± 106 ms/m) (p = 0.003 and p < 0.001, respectively). In conclusion, target distance affected the kick performance; as distance increases, impact force decreased and reaction time increased. Therefore, when reaction to a simple visual stimulus is needed, kicking from a long distance is not recommended, as longer time is required to respond. 相似文献
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Isaac Estevan Julia Freedman Silvernail Daniel Jandacka Coral Falco 《Journal of sports sciences》2016,34(18):1766-1773
The initial stance position (ISP) has been observed as a factor affecting the execution technique during taekwondo kicks. In the present study, authors aimed to analyse a roundhouse kick to the chest by measuring movement coordination and the variability of coordination and comparing this across the different ISP (0°, 45° and 90°). Eight experienced taekwondo athletes performed consecutive kicking trials in random order from every of the three relative positions. The execution was divided into three phases (stance, first swing and second swing phase). A motion capture system was used to measure athletes’ angular displacement of pelvis and thigh. A modified vector coding technique was used to quantify the coordination of the segments which contributed to the overall movement. The variability of this coordination (CV) for each ISP was also calculated. Comparative analysis showed that during the stance phase in the transverse plane, athletes coordinated movement of the trunk and thigh with a higher frequency of in-phase and lower frequency of exclusive thigh rotation in the 0° stance than the 90° stance position (P < 0.05). CV was also influenced by the different ISP. During the first swing and the majority of the second swing phase, predominant in-phase coordination of the pelvis and thigh was observed. Including exercises that require in-phase movement could not only help athletes to acquire coordination stability but also efficiency. The existence of a constraint such as ISP implies an increase of the variability when the athletes have to kick from ISP they are not used to adopt (i.e., 0° and 90° ISP) as an evidence of adaptability in the athletes’ execution technique. 相似文献
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Martinez Antonio Estevan Gehrtz Jessica Rasmussen Chris LaTona-Tequida Talia Vroom Kristen 《Innovative Higher Education》2022,47(2):327-346
Innovative Higher Education - One way that university mathematics departments across the United States are making efforts to improve their introductory mathematics courses is by implementing or... 相似文献
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Sunčica Macura Milovanović Ivana Batarelo Kokić Selma Džemidžić Kristiansen Ibolya Gera Estevan Ikonomi Lejla Kafedžić 《International Journal of Inclusive Education》2013,17(1):36-54
The article summarises the socio-political, cultural, economic and educational background to the Western Balkans region and outlines the wider qualitative research study that provided the data on early and pre-school educational opportunities in the seven countries involved; Albania, Bosnia and Herzegovina, Croatia, Kosovo (under United Nations Security Council Resolution 1244), the Former Yugoslav Republic of Macedonia, Montenegro and Serbia. The authors examine international research and literature on early education that identifies it as an important means of enabling subsequent educational and social inclusion and attainment. They proceed to discuss and illustrate from the research data five inter-linked factors showing that provision of early education in the Western Balkans is inadequate and exclusive and that children who are already at greatest socio-economic and cultural disadvantage and at potential risk in elementary and secondary education are least likely to participate in, or benefit from, it. Some recent more encouraging developments are noted but the article concludes that substantially more investment and positive actions are needed in raising awareness of the importance of early education and in developing policies and provision for it that will benefit children currently at greatest disadvantage. 相似文献
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AbstractIn taekwondo, the stance position can potentially affect kick performance. The aim of this study was to analyse mechanical variables in the roundhouse kick in taekwondo according to three stance positions (0°, 45°, 90°). Nine experienced taekwondo athletes performed consecutive kicking trials in a random order according to these three relative positions of the feet on the ground. Measurements for the mechanical analysis were performed using two 3D force plates and an eight-camera motion capture system. The taekwondo athletes’ reaction and execution times were shorter when starting from the 0° and 45° stance positions than from the 90° position (P < 0.05). Moreover, the ground reaction force was negatively correlated with execution time and positively with velocity of thigh and shank. Our results suggest that the stance position affects the execution technique of taekwondo athletes’ kicks. It is suggested that athletes should not adopt the 90° stance position because it will not enable them to achieve the best performance in the roundhouse kick. 相似文献
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Isaac Estevan Xavier García-Massó Javier Molina García Lisa M. Barnett 《Journal of sports sciences》2019,37(12):1356-1364
This study aims to develop profiles in children according to physical fitness, actual and perceived motor competence, and to examine the level of engagement in physical activity and weight status according to these profiles. In the study, 156 typically developing Spanish children (47.4% girls) of primary school age (5–11 years-old) participated voluntarily. Children’s perceived and actual motor competence, physical fitness, physical activity participation and weight status were assessed. A Self-Organising Map and K-means cluster analysis were used to classify and visualise the values. Four profiles were found: profile 2 was aligned – high capacity, high perception, profile 1 was partially aligned – medium capacity and perception, profile 3 and 4 were both non-aligned – low capacity, medium perception and medium capacity, low perception; respectively. Children in profile 2 were more active than children in profile 3 and 4 (P < .05). In profile 2 there was a lower frequency of overweight/obese children than normal-weight children. On the contrary, in profiles 1, 3 and 4 a similar distribution of normal-weight and overweight/obese children was found. High capable children with high perception exhibited higher physical activity participation and were more likely to be of normal-weight compared to those with low capacity and/or perception. 相似文献
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Participation in organized sports is promoted as a means of increasing physical activity levels and reducing chronic disease risk in adults. Hard martial arts practice (i.e. using body contact techniques), has gained in popularity over time. This review explores the evidence for health benefits of “hard” martial arts practice within the adult population. A systematic electronic database search was conducted, and quality assessments applied the Effective Public Health Practice Project tool. Twenty-eight studies met the inclusion criteria, examining balance, cognitive function, muscular skeletal status, psychological, cardiovascular fitness, and metabolic effects. The majority of studies reported positive effects resulting from hard martial arts practice, showing some improvement and maintenance of balance, cognitive function and psychological health. Benefits may be obtained regardless of the age of practice commencement. However, quality of the evidence is affected by methodological weaknesses across the studies. “Hard” martial arts seem to have potential to improve balance and cognitive functions that decline with age, which can lead to poorer health outcomes among the elderly (e.g. cognitive decline, falls and fractures). Benefits should be further investigated with improved intervention studies, representative samples and longer follow-up periods in order to establish associations with morbidity and mortality in the long term. 相似文献
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