Circadian rhythm effect on physical tennis performance in trained male players     

Álvaro López-Samanes  Diego Moreno-Pérez  José L. Maté-Muñoz  Raúl Domínguez  Jesús G. Pallarés  Ricardo Mora-Rodriguez 《Journal of sports sciences》2017,35(21):2121-2128

To determine the effect of circadian rhythm on neuromuscular responses and kinematics related to physical tennis performance, after a standardised warm-up, 13 highly competitive male tennis players were tested twice for serve velocity/accuracy (SVA), countermovement vertical jump (CMJ), isometric handgrip strength (IS), agility T-test (AGIL) and a 10-m sprint (10-m RUN). In a randomised, counter-balance order, tennis players underwent the test battery twice, either in the morning (i.e., AM; 9:00 h) and in the afternoon (i.e., PM; 16:30 h). Paired t-tests were used to analyse differences due to time-of-day in performance variables. Comparison of morning versus afternoon testing revealed that SVA (168.5 ± 6.5 vs. 175.2 ± 6.1 km · h^?1; P = 0.003; effect size [ES] = 1.07), CMJ (32.2 ± 0.9 vs. 33.7 ± 1.1 cm; P = 0.018; ES = 1.46), AGIL (10.14 ± 0.1 vs. 9.91 ± 0.2 s; P = 0.007; ES = 1.23) and 10-m RUN time (1.74 ± 0.1 vs. 1.69 ± 0.1 s; P = 0.021; ES = 0.67) were significantly blunted during the morning testing. However, IS was not affected by time-of-day (P = 0.891). Thus, tennis performance may be reduced when competing in the morning in comparison to early evening. Therefore, coaches and tennis players should focus on schedule the SVA, power, speed and agility training sessions in the afternoon.  相似文献   

On the identity of edwardsite and monazite,by Gustav Rose,extracted from the 1st No. of poggendorf's “annalen der physik und der chemie” for 1840     

M.H. Boyé  J.C. Booth 《Journal of The Franklin Institute》1840,29(5):289-290

  相似文献   

Self-controlled feedback in 10-year-old children: higher feedback frequencies enhance learning     

Chiviacowsky S  Wulf G  de Medeiros FL  Kaefer A  Wally R 《Research quarterly for exercise and sport》2008,79(1):122-127

  相似文献   

A season-long team-building intervention: examining the effect of team goal setting on cohesion     

Senécal J  Loughead TM  Bloom GA 《运动与训练心理学杂志》2008,30(2):186-199

The purpose of the current study was to determine whether the implementation of a season-long team-building intervention program using team goal setting increased perceptions of cohesion. The participants were 86 female high school basketball players from 8 teams. The teams were randomly assigned to either an experimental team goal-setting or control condition. Each participant completed the Group Environment Questionnaire (GEQ; Carron, Brawley, & Widmeyer, 2002; Carron, Widmeyer, & Brawley, 1985), which assessed cohesion at both the beginning and end of the season. Overall, the results revealed a significant multivariate effect, Pillai's trace F(12, 438) = 2.68, p = .002. Post hoc analyses showed that at the beginning of the season, athletes from both conditions did not differ in their perceptions of cohesion. However, at the end of the season, athletes in the team goal-setting condition held higher perceptions of cohesion than athletes in the control condition. Overall, the results indicated that team goal setting was an effective team-building tool for influencing cohesiveness in sport teams.  相似文献   

Training administrators and educational administration requirements     

Alberto Gutiérrez Reñón 《Prospects》1977,7(1):73-81

  相似文献   

On metrics matched to the discrete memoryless channel     

Gérald Séguin 《Journal of The Franklin Institute》1980,309(3):179-189

A sequence of metrics {D_N} is said to be additive and matched to a discrete memoryless channel (DMC) if D_N is the sum on its coordinates of N single letter metrics and if the maximum likelihood decoder for sequences of length N is a minimum D_N-distance decoder. Necessary and sufficient conditions on the transition probabilities of a DMC for the existence of a sequence of additive metrics matched to it are given. In the case of the binary channel these are shown to be equivalent to the channel being symmetric. Explicit transition probabilities are given for a large class of ternary DMCs with an associated sequence of additive matched metrics. The problem solved here may be considered a generalization of the problem of finding the DMCs matched to the Lee metric solved by Chiang and Wolf in 1971 (2).  相似文献   

Self-management in Yugoslav universities     

Branko Pribiévić Ph.D.  Jovan Ghgorijević Ph.D. 《Prospects》1973,3(4):515-521

  相似文献   

The comprehensive versus selective school issue: Introductory remarks     

Torsten Husén 《International Review of Education/Internationale Zeitschrift für Erziehungswissenschaft/Revue internationale l'éducation》1971,17(1):3-10

  相似文献   

An example of the passage from the concrete to the manipulation of formal systems     

Zoltan P. Diénès 《Educational Studies in Mathematics》1971,3(3-4):337-352

  相似文献   

Understanding Leadership in Major Sporting Events: The Case of the 2005 World Aquatics Championships     

Milena M. Parent  Denise Olver  Benoit Séguin 《Sport Management Review》2009,12(3):167-184

The purpose of this paper was to begin understanding leadership within a major sporting event. A case study of the 2005 Fédération Internationale de Natation (FINA) World Aquatics Championships was built by means of interviews and archival material, using a multi-stakeholder perspective. Findings highlighted that core elements of upper-management level leadership in events were best described by the multiple-linkage leadership theory, which includes task commitment, ability and role clarity, work organization, cooperation and mutual trust, resources and support, and external coordination as the six intervening variables. While charismatic and transformational leadership styles surfaced as contributing to the overall success of an event, the multiple-linkage leadership theory offered a more comprehensive understanding of leadership in major sporting events from a multi-stakeholder perspective.  相似文献