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Le Touquet – Paris-Plage, France

Chennaoui M.,French Armed Forces Biomedical Research Institute | Chennaoui M.,University of Paris Descartes | Bougard C.,French Armed Forces Biomedical Research Institute | Bougard C.,University of Paris Descartes | And 7 more authors.
Frontiers in Physiology | Year: 2016

The aim of this study was to evaluate stress markers, mood states, and sleep indicators in high-level swimmers during a major 7-days competition according to the outcomes. Nine swimmers [six men and three women (age: 22 ± 2 and 22 ± 4 years, respectively)] were examined. Before (PRE) and after (POST) each race (series, semi-finals, and finals), salivary concentrations of cortisol, a-amylase (sAA), and chromogranin-A (CgA) were determined. Mood states were assessed by the profile of mood state (POMS) questionnaire completed before and after the 7-days, and self-reported sleep diaries were completed daily. In the "failure" group, cortisol and sAA significantly increased between PRE-POST measurements (p < 0.05), while sCgA was not changed. Significant overall decrease of cortisol (-52.6%) and increase of sAA (+68.7%) was shown in the "failure group." In this group, fatigue, confusion and depression scores, and sleep duration before the finals increased. The results in the "success" group show tendencies for increased cortisol and sCgA concentrations in response to competition, while sAA was not changed. Cortisol levels before the semi-finals and finals and sCgA levels before the finals were positively correlated to the fatigue score in the "failure" group only (r = 0.89). sAA levels before and after the semi-finals were negatively correlated to sleep duration measured in the subsequent night (r = -0.90). In conclusion, the stress of the competition could trigger a negative mood profile and sleep disturbance which correspond to different responses of biomarkers related to the hypothalamo-pituitary-adrenal axis and the sympathetic nervous system (SNS) activity, cortisol, sAA, and CgA. © 2016 Chennaoui, Bougard, Drogou, Langrume, Miller, Gomez-Merino and Vergnoux. Source


Bonnefoy-Mazure A.,Scientific Expertise Center | Slawinski J.,Scientific Expertise Center | Riquet A.,Scientific Expertise Center | Leveque J.-M.,Scientific Expertise Center | And 2 more authors.
Journal of Biomechanics | Year: 2010

The aim of this study was to test three different rotation sequences (YXY, ZXY, and XZY) on the shoulder kinematics (rotations of the humerus relative to the thorax) during an original movement such as the tennis flat serve (FS). Nine elite male and female players performed a minimum of five flat serves. An optoelectronic motion analysis system was used to record the movements. Segment kinematics during each FS was reconstructed from the spatial trajectories of the markers according to ISB recommendations. For each rotation sequence, three angles were reported for the shoulder joint, each corresponding to a rotation component around a defined axis. The occurrence of gimbal lock (GL) and angle amplitude coherences were examined. From these three rotation sequences tested, it appears that the XZY sequence was the only decomposition not to suffer from GL. Moreover, the rotation sequence XZY was found to be coherent for all rotation components. Thus, these results show that the best rotation sequence, from both GL and amplitude coherence points of view, is XZY to describe the shoulder kinematics during the tennis serve. © 2010 Elsevier Ltd. Source


Slawinski J.,Scientific Expertise Center | Bonnefoy A.,Scientific Expertise Center | Ontanon G.,Scientific Expertise Center | Leveque J.M.,Scientific Expertise Center | And 6 more authors.
Journal of Biomechanics | Year: 2010

The aim of the present study was to measure during a sprint start the joint angular velocity and the kinetic energy of the different segments in elite sprinters. This was performed using a 3D kinematic analysis of the whole body. Eight elite sprinters (10.30±0.14s 100m time), equipped with 63 passive reflective markers, realised four maximal 10m sprints start on an indoor track. An opto-electronic Motion Analysis® system consisting of 12 digital cameras (250Hz) was used to collect the 3D marker trajectories. During the pushing phase on the blocks, the 3D angular velocity vector and its norm were calculated for each joint. The kinetic energy of 16 segments of the lower and upper limbs and of the total body was calculated. The 3D kinematic analysis of the whole body demonstrated that joints such as shoulders, thoracic or hips did not reach their maximal angular velocity with a movement of flexion-extension, but with a combination of flexion-extension, abduction-adduction and internal-external rotation. The maximal kinetic energy of the total body was reached before clearing block (respectively, 537±59.3J vs. 514.9±66.0J; p0.01). These results suggested that a better synchronization between the upper and lower limbs could increase the efficiency of pushing phase on the blocks. Besides, to understand low interindividual variances in the sprint start performance in elite athletes, a 3D complete body kinematic analysis shall be used. © 2010 Elsevier Ltd. Source


Slawinski J.,Scientific Expertise Center | Bonnefoy A.,Scientific Expertise Center | Leveque J.-M.,Scientific Expertise Center | Ontanon G.,Scientific Expertise Center | And 3 more authors.
Journal of Strength and Conditioning Research | Year: 2010

The purpose of this study was to compare the main kinematic, kinetic, and dynamic parameters of elite and well-trained sprinters during the starting block phase and the 2 subsequent steps. Six elite sprinters (10.06-10.43 s/100 m) and 6 well-trained sprinters (11.01-11.80 s/100 m) equipped with 63 passive reflective markers performed 4 maximal 10 m sprint starts on an indoor track. An optoelectronic motion analysis system consisting of 12 digital cameras (250 Hz) was used to record 3D marker trajectories. At the times "on your marks," "set," "clearing the block,"and "landing and toe-off of the first and second step," the horizontal position of the center of mass (CM), its velocity (XCMand VCM), and the horizontal position of the rear and front hand (XHand-rear and XHand-front) were calculated. During the pushing phase on the starting block and the 2 first steps, the rate of force development and the impulse (Fimpulse) were also calculated. The main results showed that at each time XCM and VCM were significantly greater in elite sprinters. Moreover, during the pushing phase on the block, the rate of force development and Fimpulse were significantly greater in elite sprinters (respectively, 15,505 ± 5,397 N·s-1 and 8,459 ± 3,811 N·s-1 for the rate of force development; 276.2 6 36.0 N·s and 215.4 ± 28.5 N·s for Fimpulse, p ≤ 0.05). Finally, at the block clearing, elite sprinters showed a greater XHand-rear and XHand-front than well-trained sprinters (respectively, 0.076 0.12 m and 20.27 ± 0.36 m for X Hand-rear; 1.00 ± 0.14 m and 0.52 ± 0.27 m for X Hand-front; p ≤ 0.05). The muscular strength and arm coordination appear to characterize the efficiency of the sprint start. To improve speed capacities of their athletes, coaches must include in their habitual training sessions of resistance training. © 2010 National Strength and Conditioning Association. Source

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