1,721,175 research outputs found
Reliability characteristics and applicability of a repeated sprint ability test in male young soccer players
Full text linkCastagna, C, Lorenzo, F, Krustrup, P, Fernandes-da-Silva, J, Po ́ voas, SCA, Bernardini, A, and D’Ottavio, S. Reliability charac- teristics and applicability of a repeated sprint ability test in male young soccer players. J Strength Cond Res XX(X): 000–000, 2017—The aim of this study was to examine the usefulness and reliability characteristics of a repeated sprint ability test consider- ing 5 line sprints of 30 m interspersed with 30 seconds of active recovery in nonelite, outfield, young, male soccer players. Twenty- six (age, 14.9 6 1.2 years; height, 1.72 6 0.12 cm; body mass, 62.2 6 5.1 kg) players were tested 48 hours and 7 days apart for 5 3 30-m performance over 5 trials (T1–T5). Short-term (T1–T2) and long-term (T1–T3–T4–T5) reliabilities were assessed with intraclass correlation coefficient (ICC) and with typical error for measurement (TEM). Short- and long-term reliability ICCs and TEMs for total sprint time and best sprint performance were nearly perfect and satisfactory, respectively. Usefulness (as smallest worthwhile change and TEM ratio) resulted acceptable (i.e., = 1) and good (i.e., .1) for total sprint time and best sprint perfor- mance, respectively. The present study revealed that the 5 3 30-m sprint test is a reliable field test in short and long terms when the sum of sprint times and the best sprint performance are considered as outcome variables. Sprint performance decre- ments variables showed large variability across trials
Estimation of maximal heart rate in recreational football: a field study
No full textPURPOSE:To examine the accuracy of practical indirect methods (i.e., recreational football match and estimation equations) in assessing individual maximal heart rate (HRmax) in recreational football players. Sixty-two untrained male participants engaged in a recreational football intervention (age 39.3 ± 5.8 years, VO2max 41.2 ± 6.2 ml·kg-1·min-1, body mass 81.9 ± 10.8 kg, height 173.2 ± 6.4 cm) were tested for HRmax using a multiple approach, at baseline and post-intervention (i.e., in the untrained and trained status, respectively). Observed HRmax was plotted against peak match HR (Match-HRpeak) and HRmax estimated from prediction equations (EstHRmax) at both time-points. RESULTS:In the untrained status, only the 211 - 0.64 × Age and 226 - Age equations showed non-significant (medium-to-small) differences with observed HRmax. The differences between observed HRmax and Match-HRpeak were large (P 0.05). The exception was for the 226 - Age and 211 - 0.64 × Age equations, with values largely higher than Post-HRmax. CONCLUSIONS:This study suggests caution when considering EstHRmax and Match-HRpeak in recreational football interventions to track HRmax. The accuracy of EstHRmax may vary according to training status, suggesting the need for different approaches and equations across training interventions
Development and voluntarism in football clubs
No full textVolunteers are still the most important resource for amateur football clubs. However, stable
voluntary engagement can no longer be granted. This difficulty is confirmed by existing research
across various European countries. From a club management point of view, a detailed
understanding of how to attract volunteers and retain them is becoming a high priority. The purpose
of this study is (1) to analyse the influence of individual characteristics and corresponding
organisational conditions on volunteering and (2) to examine the decision-making processes in
relation to implement effective strategies for recruiting volunteers. To answer these questions, the
current state of research is summarised and then a multi-level-framework is developed which is
based on the structural-individualistic social theory. The individual and context factors for
volunteering are estimated in different multi-level models based on a sample of n=1,434 sport club
members from 36 sport clubs in Switzerland. Results indicate that volunteering is not just an
outcome of individual characteristics such as lower workloads, higher income, children belonging
to the sport club, longer club membership, or a strong commitment to the club. It is also influenced
by club-specific structural conditions. Concerning decision-making processes an in-depth analysis
of recruitment practices for volunteers was conducted in selected clubs (case study design). based on the garbage can model. The results show that systematically designed decision-making processes
with a clear regulation of responsibilities seem to solve personnel problems more purposefully and
more quickly. Based on the findings some recommendations for volunteer management in football
clubs are worked out
Yo-Yo intermittent tests are a valid tool for aerobic fitness assessment in recreational football
No full textPurpose: To examine the suitability of three versions and two levels of the Yo-Yo intermittent tests for assessing and tracking aerobic fitness status development in male recreational football players. Sixty-six untrained participants (age 39 ± 6 years, VO2max 41.2 ± 6.2 ml kg−1 min−1, body mass 81.9 ± 10.8 kg, height 173.2 ± 6.4 cm) partook in a 12-week recreational football training program. They were evaluated during the Yo-Yo intermittent endurance level 1 (YYIE1) and 2 (YYIE2) tests and the Yo-Yo intermittent recovery level 1 test (YYIR1), and during a treadmill test for VO2max assessment, at baseline. Thirty-two out of these 66 participants replicated all these tests at post-intervention. An additional group of 30 male age-matched recreational football players that afterwards started the 12-week recreational football program (age 39 ± 6 years, VO2max 45.3 ± 5.8 ml kg−1 min−1, body mass 82.5 ± 7.8 kg, height 172.8 ± 5.4 cm) was evaluated at baseline to test cross-validation. Results: The Yo-Yo tests showed very large associations with VO2max at baseline (r = 0.75–0.77; P < 0.0001) and at post-intervention (r = 0.76–0.82; P < 0.0005). Post-training, very large associations were found between YYIE2 performance and VO2max (r = 0.65, P < 0.0001). Cross-validation revealed small to large differences between the observed and estimated VO2max values (1.5–2.96 ml kg−1 min−1) with moderate typical error of estimation (7.9–8.7%) across the tests. Performance in the YYIE1, YYIE2 and YYIR1 tests of ≥ 1760, 480 and 600 m, respectively, indicated good to excellent VO2max values. Conclusions: The Yo-Yo tests considered here showed robust and consistent criterion validity. The YYIE2 could be a more accurate option to track aerobic fitness development in recreational football players.</p
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
Heart Rate and Perceived Experience Differ Markedly for Children in Same- versus Mixed-Gender Soccer Played as Small- and Large-Sided Games
Full text linkThis study examines heart rate (HR) and perceived experience during same- versus mixed-gender soccer played as small- (SSG) and large-sided (LSG) games. HR, rating of perceived exertion (RPE), and fun scores were determined in 134 pupils (50 girls, 84 boys) randomly assigned to same- and mixed-genders formats playing 2x15-min of SSG (2v2, 4v4) and LSG (12v12) in a random order (50 m2/player). HR was lower (p≤0.03) for girls when playing together with boys than when playing alone (71±10 versus 77±7%HRmax), while being similar for boys playing mixed- or same-gender games (74±7 versus 77±4%HRmax). Boys perceived less fun when playing together with girls than when playing alone (4.4±2.3 versus 6.3±2.3, p<0.001). Irrespective of gender, higher (p<0.001) HRmean, %time>80%HRmax, and RPE were observed during 2v2 (78±9%HRmax, 43±33%, 5.5±2.5) and 4v4 (76±9%HRmax, 39±32%, 5.5±2.7) than during 12v12 (70±10%HRmax, 23±27%, 3.8±2.9). Cardiovascular strain was lower for girls when playing together with boys than when playing alone in LSG. SSG were more intense than LSG when girls played mixed-gender games and when boys played mixed- and same-gender games. When boys played mixed-gender games, SSG were considered more fun than LSG. Physical education teachers and coaches should consider gender and game format differences when using soccer.</p
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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