Carbohydrate intake and training efficacy – a randomized cross-over study     

Florian Beaudouin  Frederic Joerg  Anette Hilpert  Tim Meyer  Anne Hecksteden 《Journal of sports sciences》2018,36(8):942-948

Carbohydrate (CHO) availability during endurance exercise seems to attenuate exercise-induced perturbations of cellular homeostasis and might consequently diminish the stimulus for training adaptation. Therefore, a negative effect of CHO intake on endurance training efficacy seems plausible. This study aimed to test the influence of carbohydrate intake on the efficacy of an endurance training program on previously untrained healthy adults. A randomized cross-over trial (8-week wash-out period) was conducted in 23 men and women with two 8-week training periods (with vs. without intake of 50g glucose before each training bout). Training intervention consisted of 4x45 min running/walking sessions/week at 70% of heart rate reserve. Exhaustive, ramp-shaped exercise tests with gas exchange measurements were conducted before and after each training period. Outcome measures were maximum oxygen uptake (VO_2max) and ventilatory anaerobic threshold (VT). VO_2max and VT increased after training regardless of CHO intake (VO_2max: Non-CHO 2.6 ± 3.0 ml*min^?1*kg^?1 p = 0.004; CHO 1.4 ± 2.5 ml*min^?1*kg^?1 p = 0.049; VT: Non-CHO 4.2 ± 4.2 ml*min^?1*kg^?1 p < 0.001; CHO 3.0 ± 4.2 ml*min^?1*kg^?1 p = 0.003). The 95% confidence interval (CI) for the difference between conditions was between +0.1 and +2.1 ml*min^?1*kg^?1 for VO_2max and between ?1.2 and +3.1 for VT. It is concluded that carbohydrate intake could potentially impair the efficacy of an endurance training program.  相似文献   

Sport team personality: It’s not all about winning!     

Ashley Stadler Blank  Joerg Koenigstorfer  Hans Baumgartner 《Sport Management Review》2018,21(2):114-132

As there is still no commonly accepted scale to measure the brand personality of sport teams, the purpose of this study was to develop and validate the Sport Team Personality Scale (STPS) in a professional sport context. The authors conducted a series of studies in the United States and United Kingdom with fans of the English Premier League, Major League Baseball, the National Basketball Association, the National Football League, and the National Hockey League. The STPS contains 18 items that load onto six factors: success, talent, entertainment, dedication, admiration, and care. The authors compared this new scale with existing sport team personality scales and used it to explore team identification and perceptual similarities and differences among teams. Results indicate that teams map along performance (i.e., success and talent) and character (i.e., admiration and care) factors and that the character factor is a more important source of team identification than the performance factor. Taken together, these results illustrate how the STPS can help sport managers position and differentiate teams within a league to improve marketing outcomes.  相似文献   

Multiple-Group Analysis Using the sem Package in the R System     

Joerg Evermann 《Structural equation modeling》2013,20(4):677-702

Multiple-group analysis in covariance-based structural equation modeling (SEM) is an important technique to ensure the invariance of latent construct measurements and the validity of theoretical models across different subpopulations. However, not all SEM software packages provide multiple-group analysis capabilities. The sem package for the R system, which holds an important position as the only open-source SEM software, does not currently offer multigroup analysis. This article offers an alternative to true multigroup modeling that is easy to understand and apply in the R software. It is limited, however, by the constraint that groups require equal sample size.  相似文献   

Human handedness in interactive situations: Negative perceptual frequency effects can be reversed!     

Jörg Schorer  Florian Loffing  Norbert Hagemann  Joseph Baker 《Journal of sports sciences》2013,31(5):507-513

Abstract

Left-handed performers seem to enjoy an advantage in interactive sports. Researchers suggest this is predominantly due to the relative scarcity of left-handers compared with right-handers. Such negative frequency-dependent advantages are likely to appear in inefficient game-play behaviour against left-handed opponents such as reduced ability to correctly anticipate left-handers' action intentions. We used a pre–post retention design to test whether such negative frequency-dependent perceptual effects can be reversed via effective training. In a video-based test, 30 handball novices anticipated the shot outcome of temporally occluded handball penalties thrown by right- and left-handed players. Between the pre- and post-tests, participants underwent a perceptual training programme to improve prediction accuracy, followed by an unfilled retention test one week later. Participants were divided into two hand-specific training groups (i.e. only right- or left-handed shots were presented during training) and a mixed group (i.e. both right- and left-handed shots were presented). Our results support the negative frequency-dependent advantage hypothesis, as hand-specific perceptual training led to side-specific improvement of anticipation skills. Similarly, findings provide experimental evidence to support the contention that negatively frequency-dependent selection mechanisms contributed to the maintenance of the handedness polymorphism.  相似文献