References of "Jidovtseff, Boris"
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See detailInterest of creatine supplementation insoccer
Miny, Kevin ULg; Burrowes, J; Jidovtseff, Boris ULg

in Science & Sports (in press)

Objectives This review article aimed to summarize the current state of understanding on creatine supplementation for soccer players. In other words, it investigated the beneficial (and potentially ... [more ▼]

Objectives This review article aimed to summarize the current state of understanding on creatine supplementation for soccer players. In other words, it investigated the beneficial (and potentially negative) effects of this supplementation on sport-specific skills and performance in soccer players. Furthermore, this article accordingly discussed the safest and most recommended protocols for the consumption of creatine by these athletes. News Studies have shown that creatine supplementation can have positive effects on sprint and vertical jump performances in soccer players. This supplementation may also enhance soccer players’ muscle strength and adaptation to a high-intensity training regimen. Besides, creatine may be able to enhance muscle glycogen (as well as phosphocreatine) storage, reduce oxidative stress, and improve muscular repair and hypertrophy. Interestingly, creatine supplementation does not seem to affect aerobic performance. Prospects and projects Soccer players could take creatine during pre-season training (3 to 5g/day) in order to help them endure a high-intensity training regimen and enhance their muscular strength and adaptation resulting from strength and/or resistance training. A lower dosage (less than 3g/day) might also be sufficient and beneficial during the season in case of fatigue, in order to sustain adequate levels of phosphocreatine and glycogen in the muscles. Occasional intakes (about 3g) before games and/or extenuating practices could also give a physical and mental boost to the players. Conclusion Most of the studies measured the effects of creatine on skills or physical performances in isolation from the true athletic demands of soccer match play. In conclusion, there is still a need for more research in order to determine whether creatine supplementation is ergogenic regarding the (aerobic) capacity to repeat (very) high-intensity actions, more particularly during competitive soccer. [less ▲]

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See detailForce-Velocity-Power Profiles in Elite Young Soccer Players
Miny, Kevin ULg; Jidovtseff, Boris ULg

Poster (2016, November 30)

The main purpose of this research was to assess the isoinertial Force-Velocity-Power (F-V-P) profile in young elite soccer players. Furthermore, this research aims to compare force, velocity and power ... [more ▼]

The main purpose of this research was to assess the isoinertial Force-Velocity-Power (F-V-P) profile in young elite soccer players. Furthermore, this research aims to compare force, velocity and power qualities among different age categories (under (U) 17, U19 & U21). The ultimate objective is to better understand the relationships between neuromuscular system and functional performance. [less ▲]

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See detailThe influence of specific training on the plyometric profile
Jidovtseff, Boris ULg; Harris, Nigel; Carpent, Nicolas et al

Poster (2016, November 30)

Sprinting, jumping and change of direction involve the stretch-shorten cycle (SSC) and therefore plyometric training is used to improve these factors. It has been demonstrated that the jumping strategy ... [more ▼]

Sprinting, jumping and change of direction involve the stretch-shorten cycle (SSC) and therefore plyometric training is used to improve these factors. It has been demonstrated that the jumping strategy utilized can influence the biomechanical profile of the exercise and subsequent adaptation. For example, in some cases, it is important to jump as high as possible while in other cases it is important to reduce the ground contact time. Our hypothesis is that the choice of plyometric exercise has to be matched to the desired biomechanical adaptation. Hence we investigated the influence of 8 weeks of different programs on the plyometric profile of recreational athletes. In each of five groups, very specific exercises were selected according to the training objective: ground contact time group (CT, n=9); vertical jump height group (JH, n=9); CT and JH combination group (CT-JH, n=11); JH + strength training group (JH-S, n=9); and control group (CO, n=8). The plyometric profile performed prior to and post training included measures of jump height, contact time, stiffness and reactivity at different bounding intensities. The results demonstrated that JH and JH-S programs were more effective for improving jump height performance (+7-9%; p<0.005) compared to insignificant jump height changes in the CT and CO groups. CT-JH was the most effective on the reactivity index (+14%, p<0.005) although significant increases (+8%, p<0.05) were also observed in CT, JH and JH-S groups. CT was the only group to significantly decrease short contact time (-5%, p<0.05). ANOVA analysis revealed significant groups*session effect for jump height (p<0.01) and reactivity (p<0.005) but not for short contact time. The present study confirms that the principle of specificity is fundamental in plyometric training so the exercise selection should be developed cognizant of intended adaptations. Jump height and reactivity appear to be differentially affected by specific training practices. [less ▲]

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See detailThe influence of isoinertial-pneumatic ratio on force-velocity-power relationships
Jidovtseff, Boris ULg; Avrillon, Simon; Hug, François et al

Conference (2016, November 29)

Introduction: Isoinertial contractions are effective to generate maximal force during the initiation of the movement whereas they do not provide an appropriate training stimulus to generate force once ... [more ▼]

Introduction: Isoinertial contractions are effective to generate maximal force during the initiation of the movement whereas they do not provide an appropriate training stimulus to generate force once accelerative phase has been developed (1). Pneumatic resistance is one alternative that has been developed to overcome the aforementioned limitations associated with isoinertial contractions. This technique allow higher initial velocity and reduce the decrease of force towards the end of the concentric phase (1). There is some training interest by combining isoinertial and pneumatic loading. The aim of this study was to determine how different isoinertial-pneumatic ratio influence the force-velocity-power relationships during bench-press. Methods: Fifteen participants performed bench press at 30%, 45%, 60%, 75%, and 90% of their 1RM, with five isoinertial(I)-pneumatic(P) resistance ratio : 100%I/0%P, 75%I/25%P, 50%I/50%P, 25%I/75%P, and 0%I/100%P. Velocity, force and power were assessed using a linear transducer and mechanical parameters measured by the pneumatic ergometer. Force-, velocity- and power-time patterns were averaged over the push-off phase to build the corresponding force-velocity and power-velocity relationships for each resistance ratio. Results: The increase in pneumatic part in resistance ratio elicited higher movement velocity and lower force level from 0% to 80% of the concentric phase. The increase in isoinertial part in resistance balance resulted in higher velocity towards the end of the movement. As a consequence, the use of isoinertial resistance oriented the force-velocity relationship towards force, whereas pneumatic resistance elicited a more velocity-oriented profile. Conclusion: Pneumatic-oriented resistance could be used to develop initial velocity and force towards the end of the push-off. Isoinertial-oriented resistance should be used to develop maximal force and maximal power. Resistance modality could be modulated according to training objectives. Références : 1. Frost et al. A comparison of the kinematics, kinetics and muscle activity between pneumatic and free weight resistance. Eur J Appl Physiol. 2008;104:937-56. [less ▲]

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See detailLes risques de la spécialisation sportive précoce
Jidovtseff, Boris ULg

Scientific conference (2016, November 26)

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See detailAre fatigue-related EMG parameters correlated to trunk extensor muscles fatigue induced by the Sorensen test?
Demoulin, Christophe ULg; George, F.; Matheve, T. et al

in Vleeming, Andry (Ed.) 9th Interdisciplinary World Congress on Low Back and Pelvic Girdle Pain - Progress in Evidence based diagnosis and treatment (2016, November)

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See detailAssessing Basic Motor Competencies in Primary School – an International Comparative Study in Europe
Scheuer, Claude; Cloes, Marc ULg; Colella, Dario et al

Conference (2016, September 03)

A central aim of primary physical education (PE) is the promotion of physical competencies as a necessary condition of developing a physically active lifestyle and to be able to participate in the Olympic ... [more ▼]

A central aim of primary physical education (PE) is the promotion of physical competencies as a necessary condition of developing a physically active lifestyle and to be able to participate in the Olympic community. We defined basic motor competencies as physical performance dispositions, which evolved from task-specific requirements in the culture of sports and exercise. They are supposed to be learnable, based on previous experiences and can be improved through practice. Potential evaluations of effects in PE need to consider situation-specific and context-dependent characteristics of PE as well as prior experiences of pupils. Therefore, a design for test items, which are closely related to PE and vary in difficulty depending on the age of the pupils, is necessary. For this purpose, we developed the MOBAK-1 test instrument for the assessment of basic motor competencies in first graders. It allows teachers to identify groups in need of special support, and initiate these support measures to reduce inequalities. The first study took place in Zurich (Switzerland) and focused on construct validity (e.g., the factorial validity of the instrument). Between spring 2015 and spring 2016, the MOBAK-1 test instrument was and will be implemented in further countries in Europe. At this time, we have four samples of four different countries: (1) Switzerland (Zurich) (N = 317; girls = 55%; age: M = 7.04 years [SD = .37]; BMI = 16.08 [SD = 2.25]) assessed by University of Basel (Dr. Christian Herrmann); (2) Germany (Frankfurt) (N = 1061; girls = 45%; age: M = 6.80 years [SD = .89]; BMI = 16.30 [SD = 2.37]) assed by University of Frankfurt (Prof. Dr. Christopher Heim); (3) Lithuania (Kaunas) (N = 120; girls = 48%; age: M = 7.76 years [SD = .33]; BMI = 16.14 [SD = 2.30]) assessed by Lithuanian Sports University (Assoc. Prof. Dr. Arunas Emeljanovas); (4) Italy (Foggia) (N = 85; girls = 45%; age: M = 7.24 years [SD = .30]; BMI = 17.53 [SD = 3.04]) assessed by University of Foggia (Prof. Dr. Dario Colella). Further samples are currently on the way to be completed in four other countries: (1) Luxembourg (N = 280) assessed by University of Luxembourg (Claude Scheuer); (2) Slovakia (Trnava) (N = 240) assessed by University of Trnava (Dr. Dana Masarykova); (3) Czech Republic (Brno) (N = 600) assessed by University of Brno (Dr. Petr Vlcek); (4) Belgium (Liège) (N = 450) assessed by University of Liège (Prof. Dr. Marc Cloes and Dr. Boris Jidovtseff). In the initial validation study in Switzerland, two factors consisting of four items each were found. The related EFA (Study 1: CFI=.98; RMSEA=.024) and CFA (Study 2: CFI =.95; RMSEA=.044) revealed good model fit indices. The first factor “Locomotion” represents body movements (e.g., balancing), the second factor “Object-control” represents ball control (e.g., catching). Conclusions: The developed MOBAK test instrument meets psychometric validity demands based on the Swiss data. The presentation will show the results of the validation studies in further European countries and the results of the comparative study. [less ▲]

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See detailWater familiarization testing battery adapted for young children
Vandermeulen, Mary ULg; Schietecatte, Delphine; Delvaux, Anne ULg et al

Poster (2016, June 11)

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See detailModifying Indoor Facilities Appropriate to Children
Jidovtseff, Boris ULg; Delvaux, Anne ULg; Mornard, Manhattan ULg et al

in Book of abstracts AISEP 2016 (2016, June)

Introduction Physical literacy development during childhood is critical not only to favor sport performance outcomes but also to develop long term physical activity. It’s very important for children to ... [more ▼]

Introduction Physical literacy development during childhood is critical not only to favor sport performance outcomes but also to develop long term physical activity. It’s very important for children to move in a thinking way. Diversified activities are important to develop a large panel of fundamental motor skills and to stimulate perception. It is important for children to move, but it has to be done in a thinking way. Focus on inquiry With young children it is important to maximize active time, to develop fundamental motor skills and perception, to take into account inter-individual differences, to favor enjoyment, self-confidence and to guarantee optimal security. Most of these pedagogical challenges can be reached by appropriate instruction and by an adapted environment. Contribution There is clear evidence that modifying exercise facilities influence children’s behaviour with consequences for motivation, activity level and motor development. For 25 years a reflexive approach has been used at CEReKi (Liège, Belgium) in order to determine how indoor facilities can be modified with the aim to meet children needs and to favor motor development. Attractive circuits have been developed to stimulate specific motor skills (gymnastic, athletic or ball circuits). They were created to afford action possibilities and challenges for children to explore their own abilities for exercise. According to the children’s age and level of ability different pedagogical conditions can be provided: spontaneous play, guided discovery or structured games. Circuits have to be organised in such a way that children can do most exercises on their own. The arrangement of equipment offers multiple possibilities for movement, favouring active discovery for all children. The autonomy of children allows the teacher to move throughout the circuit and assist children by scaffolding their learning. Conclusion Our experience confirms that modifying indoor facilities is relevant for 3 to 8 years old children activities. [less ▲]

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See detailDas MOBAK-Netzwerk: Kulturvergleichende Perspektive aus acht europäischen Ländern
Scheuer, Claude; Cloes, Marc ULg; Colella, Dario et al

in Kaboth, Holger; Heim, Christopher; Prohl, Robert (Eds.) Bildungsforschung im Sport (2016, May 27)

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See detailL’ACCOUTUMANCE À L’EAU, UN PASSAGE OBLIGÉ AVANT LA NATATION ?
Mornard, Manhattan ULg; Delvaux, Anne ULg; Delsupexhe, Nadège et al

Poster (2016, February 27)

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See detailSPÉCIALISATION SPORTIVE PRÉCOCE : QUEL IMPACT SUR LA PERFORMANCE, SUR LE DÉVELOPPEMENT ET SUR LA SANTÉ ET QUELLES PISTES DE SOLUTION ?
Jidovtseff, Boris ULg

in Jidovtseff; Halleux, Philippe; Lambert, Eric (Eds.) Livre des résumés du 2ème colloque Guuy Namurois (de l'éducation physique à la performance sportive) (2016, February 27)

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See detailIntérêt d’un modèle de compétition adapté aux enfants en athlétisme : le Kid’s Athletics
Jidovtseff, Boris ULg; Wuillaume, Sandrine; Cloes, Marc ULg

Poster (2016, February 27)

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See detailSPÉCIALISATION SPORTIVE PRÉCOCE:QUELS RISQUES SUR LE DÉVELOPPEMENT ET SUR LA SANTE ?
Jidovtseff, Boris ULg

in Ortho-Rhumato (2016), 14(2), 21-25

Plusieurs travaux scientifiques menés dans les années 90 ont soutenu la thèse que pour espérer atteindre un jour le très haut niveau sportif, il fallait commencer un sport spécifique tôt et avec une ... [more ▼]

Plusieurs travaux scientifiques menés dans les années 90 ont soutenu la thèse que pour espérer atteindre un jour le très haut niveau sportif, il fallait commencer un sport spécifique tôt et avec une certaine intensité, ceux qui commençaient trop tard ayant très peu de chance d’atteindre l’élite sportive. La réussite de stars ayant commencé tôt, l’apparition de compétitions importantes pour les jeunes et la recherche de performance dès l’enfance ont contribué au développement de la spécialisation précoce. Pourtant, les études scientifiques montrent que cette approche n’est pas particulièrement efficace et de surcroît, peut poser des problèmes au niveau du développement de l’enfant et de sa santé. Les surcharges d’entraînement spécifique, mais aussi certains comportements alimentaires affecteraient la fonction endocrine. La répétition intense de gestes stéréotypés favoriserait l’apparition des blessures. D’autres éléments comme la pression, le manque d’amusement ou le manque de temps pour d’autres activités peuvent conduire l’enfant au dégoût et à l’abandon précoce. Ces dernières années, des solutions alternatives et adaptées aux enfants émergent comme les modèles de développement à long terme favorisant souvent des pratiques polysportives et une spécialisation progressive. Les modèles de compétitions qui influencent largement les pratiques doivent être revus afin de favoriser prioritairement les apprentissages moteurs et non pas rechercher la performance à tout prix. Finalement, les modèles de pratique devraient prendre en compte tous les enfants, aussi bien ceux qui souhaitent faire du sport de compétition que ceux qui souhaitent faire du sport pour leur bien-être. [less ▲]

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See detailEffects of twelve weeks of aerobic or strength training in addition to standard care in Parkinson’s disease: a controlled study
Demonceau, Marie ULg; MAQUET, Didier ULg; Jidovtseff, Boris ULg et al

in European Journal of Physical and Rehabilitation Medicine (2016), 52

BACKGROUND: Physical exercises in addition to standard care (SC) in patients with Parkinson’s disease (PD) are now common practice in many care units. However, exercises can cover a wide range of ... [more ▼]

BACKGROUND: Physical exercises in addition to standard care (SC) in patients with Parkinson’s disease (PD) are now common practice in many care units. However, exercises can cover a wide range of interventions, and the specific effects of different interventions still deserve to be further investigated. AIM: To compare the effects of 12 weeks of two different types of physical exercises with SC in patients suffering from PD. DESIGN: Pseudo-randomized controlled trial. SETTING: University laboratory for outcomes, University Hospital Centre for interventions. POPULATION: Fifty-two outpatients suffering from mild to moderate PD at baseline. METHODS: Participants were allocated to 3 groups: the strength training (ST) group performed individualized upper and lower limbs strength training, the aerobic training (AE) group performed tailored gradual aerobic cycling, and the third group received SC. The effects of the interventions on body function were assessed by measuring isokinetic concentric peak torque for knee extension and flexion, peak oxygen consumption (VO2peak) and peak work load (PWL) during an incremental maximal cycling test. Changes in mobility were evaluated from spatial-temporal gait features measured by mean of an accelerometer system and the six-minute walk distance (6mwd) test. We used questionnaires to estimate health-related quality of life and habitual physical activity. RESULTS: No significant changes in any outcome measures occurred in the SC group. More than 80% of the participants adequately completed the AE and the ST interventions. The ST group significantly improved all peak torque measures (p≤0.01), except knee extension in the least affected side (p=0.13). This group also improved the PWL (p=0.009) and 6mwd (p=0.03). The AE group improved the VO2peak (p=0.02) and PWL (p<0.001). CONCLUSION: Physical fitness in patients with PD rapidly improved in compliance with training specificities, but better fitness hardly translated into better mobility and health-related quality of life. CLINICAL REHABILITATION IMPACT: Physiotherapists can efficiently propose physical conditioning to patients with mild to moderate PD, but these interventions are insufficient to improve gait and participation. Notwithstanding, ST is an efficient intervention for improving walking capacity. [less ▲]

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See detailIs the Sørensen test valid to assess muscle fatigue of the trunk extensor muscles?
Demoulin, Christophe ULg; Boyer, Mathieu; Duchateau, Jacques et al

in Journal of Back and Musculoskeletal Rehabilitation (2016), 00

BACKGROUND: Very few studies have quantified the degree of fatigue characterized by the decline in the maximal voluntary contraction (MVC) force of the trunk extensors induced by the widely used Sørensen ... [more ▼]

BACKGROUND: Very few studies have quantified the degree of fatigue characterized by the decline in the maximal voluntary contraction (MVC) force of the trunk extensors induced by the widely used Sørensen test. OBJECTIVE: Measure the degree of fatigue of the trunk extensor muscles induced by the Sørensen test. METHODS: Eighty young healthy subjects were randomly divided into a control group (CG) and an experimental group (EG), each including 50% of the two genders. The EG performed an isometric MVC of the trunk extensors (pre-fatigue test) followed by the Sørensen test, the latter being immediately followed by another MVC (post-fatigue test). The CG performed only the preand post-fatigue tests without any exertion in between. RESULTS: The comparison of the pre- and post-fatigue tests revealed a significant (P <0.05) decrease in MVC force normalized by body mass (−13%) in the EG, whereas a small increase occurred in the CG (+2.7%, P = 0.001). CONCLUSIONS: This study shows that the Sørensen test performed until failure in a young healthy population results in a reduced ability of the trunk extensor muscles to generate maximal force, and indicates that this test is valid for the assessment of fatigue in trunk extensor muscles. [less ▲]

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See detailMODIFYING PHYSICAL ENVIRONMENT TO BE APPROPRIATE FOR CHILDREN
Jidovtseff, Boris ULg; Delvaux, Anne ULg; Mornard, Manhattan ULg

in Book of abstracts AISEP 2015 (2015, July)

Our experience confirms that adapting physical environments is critical for providing appropriate physical activity for 3 to 8 years old children.. Moreover, the pedagogy has to favour success, discovery ... [more ▼]

Our experience confirms that adapting physical environments is critical for providing appropriate physical activity for 3 to 8 years old children.. Moreover, the pedagogy has to favour success, discovery and a fun environment. This work illustrates what can be achieved and provides clear guidance for developing centres to support the promotion of physical activity in early childhood. [less ▲]

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See detailContribution à l’exploration de la performance musculaire sur le terrain
Jidovtseff, Boris ULg

Scientific conference (2015, April)

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