The aim of this study was to determine the match activity and physiological demands of women's tennis during a 3-day clay-court tennis tournament. The activity profile of eight players was determined by filming each competitive match with video cameras. Metabolic-perceptual measurements--blood samples and individual ratings of perceived exertion (RPE)--were taken while the players were sitting during permitted changeover breaks in play. The activity profile of the players was as follows: strokes per rally, 2.5 +/- 1.6; rally duration, 7.2 +/- 5.2 s; rest time between rallies, 15.5 +/- 7.3 s; effective playing time, 21.6 +/- 6.1%; work-to-rest ratio, 1:2.1. Blood lactate concentration [2.2 +/- 0.9 mmol x l(-1) (n = 50) vs. 2.2 +/- 0.7 mmol x l(-1) (n = 48)] and RPE values [12.2 +/- 2.4 (n = 57) vs. 12 +/- 2.3 (n = 57)] were not significantly different (P = 0.65-0.78) between service and return games. The results highlight the importance of taking these factors (i.e. activity patterns and physiological profile) into account when planning training strategies for competitive females players. As such, tennis training regimes should be adapted to the specific demands imposed by match-play in female players on a clay-court surface. 相似文献
The aim of this study was to examine the effect of an enrichment programme in motor, technical and tactical basketball skills, when accounting for the age of youth sport specialisation. Seventy-six college students (age: M = 20.4, SD = 1.9) were allocated according to three different paths: (i) non-structured (n = 14), (ii) early specialisation (n = 34), and (iii) late specialisation (n = 28), according to information previously provided by the participants about the quantity and type of sporting activities performed throughout their sporting careers. Then, the participants of each path were randomly distributed across control and experimental groups. Variables under study included agility, technical skills circuit, as well as tactical actions performed in a 4-on-4 full-court basketball game. The results indicated improvements in the early and late specialisation paths namely in the experimental training groups. However, the late specialisation path revealed larger benefits, in contrast with the non-structured path, which showed less sensitivity to the enrichment programme, mostly sustained in physical literacy and differential learning. Higher improvements were observed in agility, and also in reducing the number of unsuccessful actions performed during the game. Overall, this study provided evidence of how early sports experiences affect basketball skill acquisition and contribute to adapt to new contexts with motor and technical-tactical challenges. In addition, a path supported by late specialisation might present several advantages in sport performance achievement. 相似文献
The aim of this study was to identify the effects of adding spatial references during football small-sided games in youth players’ tactical and physical performance. Twelve under-15 players performed a Gk+ 6v6+ Gk game under two playing conditions: (i) without spatial references (CONTROL condition); (ii) with spatial references, by dividing equally the pitch into three corridors and three sectors (experimental situation, LINES). Players’ positional data was used to compute time-motion and tactical-related variables. The results revealed that performance under LINES situation increased the regularity in the zones occupied (~14%, Cohen’s d: 0.5; ±0.3; p = 0.003) and in the distance between teammates’ dyads (~19%, 0.9; ±0.2; p < 0.001). Oppositely, LINES condition decreased the longitudinal synchronization of players’ displacements (0.4; ±0.2; p = 0.002), players’ average speed (0.5; ±0.3; p = 0.002) and distance covered at lower (0.9; ±0.3; p < 0.001) and moderate speed (0.5; ±0.3; p < 0.001). Adding spatial references seems to promote a more structured pattern of play and increase positional regularity. However, coaches should be aware that this constraint may decrease the synchronization between players. Overall, these findings may be generalized to most invasion team sports. 相似文献
Recent studies suggest that teacher messages can affect students’ well-being. Using a multilevel, variable, and person-centred approach, this study aimed to identify profiles of students according to their teachers’ use of engaging messages and analyse the relation among these profiles and teacher-student relatedness and students’ subjective vitality. A total of 1209 students participated in the study. At the student-level, profile analysis indicated the existence of four different profiles: the few messages profile, the autonomous motivational appeals profile, the loss-framed messages profile, and the gain-framed messages profile. At the teacher level, profile analysis indicated the existence of two profiles: the variant and the invariant profiles. Results showed that overall, at both levels of analysis, teachers’ engaging messages related with teacher-student relatedness (either positively or negatively) with clear differences among profiles. Moreover, also at both levels of analysis, teacher-student relatedness related with students’ subjective vitality. Main findings and implications for practice are discussed.