1,720,965 research outputs found
Repeated High-Intensity Technique Training and Repeated Sprint Training Elicit Similar Adjustment in Physiological Responses But Divergent Perceptual Responses and Combat-Related Performances in Adolescent Taekwondo Matches
No full textPurpose: This study investigated the effects of 4 weeks of repeated sprint training (RST) versus repeated high-intensity technique training (RTT) on the physiological responses (ie, blood lactate), mean and peak heart rate, rating of perceived exertion, technical-tactical performance, and time-motion variables during simulated taekwondo combats. Methods: Twenty-four taekwondo athletes (18 male and 6 female; age: 16 [1] y) were randomly and equally assigned to RST (10 × 35-m running sprints interspersed by 10-s rest) or RTT (10 × 6-s bandal-tchagui kicking executions interspersed by 10-s rest) groups in addition to their regular training. Both groups performed simulated combats before and after training. Results: Delta lactate and peak heart rate were attenuated following training (P < .001 and P = .03, respectively), with no differences identified between RTT and RST conditions. Rating of perceived exertion decreased after training only in the RTT (P = .002). Time fighting and preparatory activities increased following training (P < .001), with higher values observed following RTT than RST (P < .001). Nonpreparatory time decreased after training (P < .001), with more pronounced reductions observed following RTT when compared to RST (P < .001). The number of single attacks decreased only following RST (P < .001), whereas combined attacks increased only after RTT training (P < .001). Conclusions: Similar adjustments in the physiological responses to combat were observed following 4 weeks of either RST or RTT, but RTT elicited more favorable perceptual responses and combat-related performance. This highlights the importance of specificity of training and its effective transfer to combat
Effects of conditioning activity mode, rest interval and effort to pause ratio on post-activation performance enhancement in taekwondo: a randomized study
Full text linkIntroduction: The present study assessed the effects of conditioning activities, using different effort-to-pause ratios and rest intervals, on taekwondo physical performance.Methods: Twenty-one athletes (13 males and 8 females) (Mean ± SD; age = 20.4 ± 1.4 years) performed a control (CC) and twelve experimental conditions. Each condition contained a standard warm-up (i.e., CC: running at 9 km/h for 10 min) and conditioning activities comprising plyometrics P) or repeated high-intensity techniques (RT) using 1:6, 1:9 and self-selected rest (SSR) ratios, and two rest intervals (3 and 7 min). Athletes then performed a battery of fitness tests: countermovement jump (CMJ), taekwondo specific agility (TSAT), 10s and multiple frequency speed kick test (FSKT-10s and FSKT-mult, respectively).Results: All of the preloads provided higher performance outputs compared to the control trial (all p < 0.05). For CMJ, 1:6 ratio with 3 min induced lower values with RT compared to P (p = 0.037) and 1:9 ratio using 3 min induced higher values with RT compared to P (p = 0.027). Additionally, 1:6 ratio using 7 min induced higher values with RT compared to P (p = 0.016). For FSKT-10, 3 min using 1:6 induced higher values with P compared to RT, while RT induced higher values with 7 min using 1:6 ratio compared to P (both p < 0.001). Moreover, 3 min using 1:9 ratio induced higher values with P compared to RT (p = 0.034), while RT induced higher values with 1:9 ratio using 7 min compared to P (p < 0.001). Finally, 3 min using SSR ratio induced higher values with RT compared to P (p = 0.034).Conclusion: Plyometrics and RT activities improved performance with plyometrics requiring shorter rest interval to induce potentiation effects compared to RT, which required longer interval
Acute effects of caffeine supplementation on taekwondo performance:the influence of competition level and sex
Full text linkThe purpose of this study was to assess the effects of acute caffeine supplementation on physical performance and perceived exertion during taekwondo-specific tasks in male and female athletes with varying expertise. In a double-blinded, randomized, placebo-controlled crossover study design, 52 young athletes from elite (n = 32; 16 males and 16 females) and sub-elite competitive level (n = 20; 10 males and 10 females) participated. Athletes performed taekwondo-specific tasks including the taekwondo-specific agility test (TSAT), 10 s frequency speed of kick test (FSKT-10 s) and multi-bout FSKT (FSKT-multi) under the following conditions: (1) Caffeine (CAF; 3 mg kg−1), placebo (PLA), and no supplement control (CON). Session rating of perceived exertion (s-RPE) was determined after the tests. Findings show that regardless of condition, males performed better than females (p < 0.05) and elite athletes had superior performance compared to their sub-elite counterparts (p < 0.05). For the TSAT (p < 0.001), FSKT-10s (p < 0.001), and FSKT-multi (p < 0.001), CAF enhanced performance in elite female athletes compared to sub-elite females. Likewise, CAF ingestion resulted in superior performance in elite males compared to sub-elite males for FSKT-10s (p = 0.003) and FSKT-multi (p < 0.01). The ergogenic potential of CAF during taekwondo-specific tasks appears to be related to a competitive level, with greater benefits in elite than sub-elite athletes
Listening to Preferred and Loud Music Enhances Taekwondo Physical Performances in Adolescent Athletes
Full text linkIn this study, we aimed to investigate the effects of warm-up music preference and loudness on physical performance, perceived exertion (RPE), and enjoyment in young taekwondo athletes. In a crossover counterbalanced design, 20 taekwondo athletes (10 male, 10 female) performed a battery of physical tasks specific to taekwondo under the following five conditions: (a) No music (NM), (b) Preferred music-Soft (60 dB; PMS), (c) Preferred music-Loud (80 dB; PML), (d) Non-preferred music-Soft (60 dB; NPMS), and (e) Non-preferred music-Loud (80 dB; NPML). On each lab visit, participants completed a taekwondo-specific agility test (TSAT), a10-second kick test (KSKT-10s) and a multiple frequency speed of kick tests (FSKT) within each music condition. Pre-exercise enjoyment was assessed using the Physical Activity Enjoyment Scale (PACES) after the warm-up, while we obtained RPE scores after each test. The PML condition resulted in significantly better agility test times on the TSAT compared to PMS (p < .001), and NPML (p < .001). Furthermore, PML led to a greater number of total kicks during the FSKT-10s test compared to the PMS (p < .001), and NPML (p < .001) conditions. The decrement index on the FSKT was lower in PML than in PMS and NPML conditions (p < .001). For RPE, values were significantly lower with preferred than non-preferred music (p < .001). These findings lend support to ergogenic benefits of listening to PML prior to taekwondo physical tasks, with important implications for enhancing taekwondo training and performance
Relationships Between Sport-Specific Anaerobic Tests, Interlimb Asymmetry, and Bilateral Deficit as Measured from Vertical Jump Performances in Highly Trained Taekwondo Athletes
Full text linkThe present study investigated the effect of inter-limb asymmetry and bilateral indexes (BLIs) in power performance, assessed by squat jump (SJ) and countermovement jump (CMJ), on sport-specific anaerobic performance. Forty-eight taekwondo athletes (24 males and 24 females; mean ± SD, age: 19.8 ± 2.1 years) performed randomly, in separate sessions, SJ and CMJ tests using the right, left, and both legs to determine the asymmetry and BLI, the 10 s Frequency Speed of Kick Test (FSKT10s), and its multiple version (FSKTmult). FSKT10s was positively correlated with CMJ asymmetry (ρ = 0.299, p = 0.039, low) and SJ BLI (r = 0.596, p < 0.001, large), and negatively correlated with CMJ BLI (r = −0.472, p = 0.001, moderate). Similarly, FSKTmult was positively correlated with SJ BLI (ρ = 0.632, p < 0.001, large), and negatively correlated with CMJ BLI (ρ = −0.532, p < 0.001, large). CMJ and SJ BLI explained 45.9% of the variance of the FSKT10s performance, whilst they explained 55.7% of the variance of FSKTmult performance. These results highlight the importance of managing both interlimb asymmetry and bilateral deficit indexes to achieve better performance by improving the strength of the non-dominant leg and using exercises that are performed bilaterally despite unilateral movements being predominant in taekwondo, which can potentially enhance the effectiveness in sport-specific action
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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