Temporal specificity of training: intra-day effects on biochemical responses and Olympic-Weightlifting performances     

Achraf Ammar  Hamdi Chtourou  Khaled Trabelsi  Johnny Padulo  Mouna Turki  Kais El Abed 《Journal of sports sciences》2015,33(4):358-368

The aim of this study was to investigate the performance of an Olympic-Weightlifting session training at three times of the day on the performance related to biochemical responses. Nine weightlifters (21 ± 0.5 years) performed, in randomised order, on three Olympic-Weightlifting training (snatch, clean and jerk) sessions (08:00 a.m., 02:00 p. m., 06:00 p. m.). Blood samples were collected: before, 3 min and 48 h after each training session. Haematological parameters and markers of muscle injury were assessed. Resting oral temperature and rating of perceived exertion (RPE) were also assessed during each session. ANOVA showed that the performance was better (P < 0.001) at 02:00 p. m. with a less RPE (P < 0.01) compared to the morning and the evening sessions while there was higher (P < 0.05) oral temperature at 06:00 p. m. versus 08:00 a.m. and 02:00 p. m. Muscle damage changed immediately (without significant effect after 48 h) after the training sessions with lower values ??in the evening compared to the morning. In conclusion, the afternoon training is more effective than morning or evening sessions for weightlifters. Therefore, coaches and weightlifters should be advised to schedule their training session in the afternoon hour.  相似文献   

Robust predictive control based on the Meixner-like model     

Safa Maraoui  Abdelkader Krifa  Kais Bouzrara 《Journal of The Franklin Institute》2019,356(12):6226-6254

This paper is devoted to the issue of a robust predictive control for linear discrete-time systems by using Meixner-like model. The Meixner-like functions are an extension of Laguerre functions and convenient when the system has a slow start or delay. To ensure the reduction of the parameter number in the Meixner-like model, the optimization of parameters characterizing the Meixner-like functions is proposed. This proposed robust predictive control copes with physical constraints and geometrical constraints due to parameter uncertainties, which are estimated by using the Unknown But Bounded Error (UBBE) approach, and leads to the min-max optimization problem.  相似文献   

Leadership and students’ academic success: mediating effects of self-efficacy and self-determination     

Kais Gannouni  Lovanirina Ramboarison-Lalao 《International Journal of Leadership in Education》2018,21(1):66-79

When exploring the effects of leadership on students, most studies have focused on either how leadership affects the students’ academic outcomes or how it contributes to their personal development. This study merged both approaches and aimed to measure the mediating effects of self-efficacy and self-determination among leadership, students’ intentions to persist and GPA. A Structural Equation Analysis was applied to a data-set of 1009 students from 39 countries to examine these relationships. The results showed a full mediating effect of academic self-efficacy between leadership and students’ intentions to persist and between leadership and GPA, and revealed a full mediating effect of self-determination through autonomy and relatedness constructs between leadership and intention to persist. This result implies that even though leadership does not directly affect students’ academic outcomes, it enhances their confidence and motivation, which provides them with the inner drive to aim high, persevere and achieve their goals. The theoretical and practical implications of these results are also discussed.  相似文献