Effects of game location, quality of opposition, number of foreign players and anthropometric characteritics in elite handball games

The aims of this study were (1) to investigate the influence of game location, quality of opposition, age of players, and anthropometric characteristics of backcourt and pivot players as well as the number of foreign players in a team on goal difference between the teams in the French (LNH) and German (Bundesliga) national men’s professional leagues, and (2) to predict goal difference of match final scores in these two national leagues using a multiple regression model. Archival data were obtained from the open access official websites to collect a sample of 165 handball matches (LNH [N=89], and Bundesliga [N=76]) of the first part of the 2015/2016 regular season. The linear regression model predicted the winner in 79% of cases with a mean accuracy of four goals. The coefficients of determination found in both multiple regression models were r²=.67 and r²=.49 for the LNH and the Bundesliga, respectively. The models revealed a high contribution of the difference in the end-of-previous season goal-average per match ranking and a moderate contribution of the game location to goal difference. The models also highlighted differences in the way games were won in these leagues with a contribution of foreigners, anthropometric characteristics and age only in the Bundesliga

La modélisation biomécanique : un outil didactique ?

Modéliser, c’est créer artificiellement une ou plusieurs variables, issues d’une démarche théorique visant à remplacer des phénomènes complexes invisibles par des phénomènes simplifiés et visibles. Deux niveaux hiérarchiques de modélisation biomécanique ont pu être dégagés, selon leurs capacités à simplifier la complexité du réel. Le premier niveau est celui de la modélisation intégrative totale, dans lequel le corps humain est réduit à une expression simplifiée, comme dans la modélisation en système masse ressort. Le corps est représenté globalement, et le discours pédagogique utilise des notions telles que l’énergie ou la force comme organisateurs cognitifs. Le deuxième niveau est celui de la modélisation cinématique multi-segmentaire intégrative, où le corps humain est alors considéré comme une entité constitutive de sous-entités dépendantes.Ceci suggère que la modélisation permet de rationaliser le discours de l’enseignant en utilisant la métaphore comme organisateur cognitif de sa pensée à travers un modèle hiérarchique dans la maîtrise du corps humain. Il permettra la construction de sens chez l’élève, en lui permettant une appropriation du savoir par une construction cognitive et active d’un corps «globalisant et maîtrisable»

Physiological, neuromuscular and perceived exertion responses in badminton games

The purpose of this study was to characterise the physiological, neuromuscular and perceived exertion variables during a badminton match and to assess the influence of these variables on the characteristics of the game. Each variable was measured before, every ten minutes, and ten and twenty minutes after a badminton game. Using a lactate device, a heart rate monitor, an accelerometric system, a dynamometer, a camera and a Borg scale, twelve games between elite players were analysed. An increase was found in the heart rate, blood lactate and in the recovery time, while a decrease was found in the power output of the lower and upper limb joints and shot frequency. These results suggest the capability of the players to preserve a high intensity of performance for as long as possible despite general fatigue. The fatigue induced by changes in physiological variables is affected more by the intensity of the stroke rather than the duration of the rallies. The perceived exertion is thought to be a combination of attentional and neuromuscular fatigue rather than related to changes in metabolites. Consequently, in future studies, researchers and trainers should consider the fatigue state as a means to increase players’ ability

Tiempo, significación y memoria en la fenomenología social de Alfred Schutz

The purpose of this paper is to investigate the approach of the social phenomenology of Alfred Schutz developed around temporality, verifying its implications on the analysis of meaning and memory. Based on the critical analysis of the fundamental concepts of the theory of Max Weber’s social action, we propose to reconstruct schutzian reading and appropriation of Husserl’s Phenomenology Lessons of Internal Consciousness of Time. In the review of this influence on theearly work of Schutz -The phenomenology of social world-, we will try to elucidate enlightening aspects of the relationship between time, meaning and memory.El propósito de este trabajo es indagar el abordaje que la fenomenología social de Alfred Schutz desarrolla en torno a la cuestión de la temporalidad, atendiendo sus implicancias en el análisis de la significación y de la memoria. Partiendo del análisis crítico de los conceptos fundamentales de la teoría de la acción social de Max Weber, nos proponemos reconstruir la lectura y apropiación schutziana de las Lecciones de fenomenología de la conciencia interna del tiempo de Husserl. En la revisión de esta influencia sobre la primera obra de Schutz -La construcción significativa del mundo social-, intentaremos elucidar aspectos esclarecedores de la relación entre tiempo, significación y memoria

Relationship between split-step timing and leg stiffness in world-class tennis players when returning fast serves

International audienc

Acute Effects of Whole-Body Vibration on the Postural Organization of Gait Initiation in Young Adults and Elderly: A Randomized Sham Intervention Study

Whole-body vibration (WBV) is a training method that exposes the entire body to mechanical oscillations while standing erect or seated on a vibrating platform. This method is nowadays commonly used by clinicians to improve specific motor outcomes in various sub-populations such as elderly and young healthy adults, either sedentary or well-trained. The present study investigated the effects of acute WBV application on the balance control mechanisms during gait initiation (GI) in young healthy adults and elderly. It was hypothesized that the balance control mechanisms at play during gait initiation may compensate each other in case one or several components are perturbed following acute WBV application, so that postural stability and/or motor performance can be maintained or even improved. It is further hypothesized that this capacity of adaptation is altered with aging. Main results showed that the effects of acute WBV application on the GI postural organization depended on the age of participants. Specifically, a positive effect was observed on dynamic stability in the young adults, while no effect was observed in the elderly. An increased stance leg stiffness was also observed in the young adults only. The positive effect of WBV on dynamic stability was ascribed to an increase in the mediolateral amplitude of ?anticipatory postural adjustments? following WBV application, which did overcompensate the potentially destabilizing effect of the increased stance leg stiffness. In elderly, no such anticipatory (nor corrective) postural adaptation was required since acute WBV application did not elicit any change in the stance leg stiffness. These results suggest that WBV application may be effective in improving dynamic stability but at the condition that participants are able to develop adaptive changes in balance control mechanisms, as did the young adults. Globally, these findings are thus in agreement with the hypothesis that balance control mechanisms are interdependent within the postural system, i.e., they may compensate each other in case one component (here the leg stiffness) is perturbed

Age- and gender-related development of stretch shortening cycle during a sub-maximal hopping task

The aim of this study was to analyse the effects of age and gender (and their interaction) on a stretch shortening cycle solicited during a hopping task. For this aim, 147 girls and 148 boys aged 11 to 20 years, who were enrolled in middle school or secondary school with no experience in sport activity, or training less than three times per week, performed 3 75 hops in place. Leg-stiffness, jump-height and reactive-strength indices were assessed using an accelerometer (Myotest). The participants were selected in order to form five age groups: 11 12, 13-14, 15-16, 17-18 and 19-20 years. Regression analysis between force and centre of mass displacement revealed spring-mass behaviour for all groups (r(2)=.73-.89), meaning that beginning at the age of 11 years, children are able to perform complex inter-muscular coordination of the lower limbs, revealing efficient neural control early in childhood. Leg stiffness increased from 24.7 \ub1 10.6 kN \ub7 m(-1) at 11-12 years to 44.1 \ub1 14 kN \ub7 m(-1) in boys, with a small increase until 16 years (+17%) and a large increase between 17 and 20 years (+32.7%). In girls, leg stiffness increased from 26.6 \ub1 9 kN \ub7 m(-1) at 11-12 years to 39.4 \ub1 10.9 kN \ub7 m(-1) at 19-20 years, with a curious decrease in leg stiffness at 17-18 years, probably due to an increase in the percentage of fat at this age (25%). While no gender effect was found, the reactive-strength index revealed that, from 15-16 years onward, boys were better able to produce high levels of force in a shorter time than girls. The age of 15-16 years is a threshold of maturity and gender differentiation, where the boys investigated are more efficient in the stretch shortening cycle

Long-Term Effects of Whole-Body Vibration on Human Gait: A Systematic Review and Meta-Analysis

Background: Whole-body vibration is commonly used in physical medicine and neuro-rehabilitation as a clinical prevention and rehabilitation tool. The goal of this systematic review is to assess the long-term effects of whole-body vibration training on gait in different populations of patients.Methods: We conducted a literature search in PubMed, Science Direct, Springer, Sage and in study references for articles published prior to 7 December 2018. We used the keywords “vibration,” “gait” and “walk” in combination with their Medical Subject Headings (MeSH) terms. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) methodology was used. Only randomized controlled trials (RCT) published in English peer-reviewed journals were included. All patient categories were selected. The duration of Whole-Body Vibration (WBV) training had to be at least 4 weeks. The outcomes accepted could be clinical or biomechanical analysis. The selection procedure was conducted by two rehabilitation experts and disagreements were resolved by a third expert. Descriptive data regarding subjects, interventions, types of vibration, training parameters and main results on gait variables were collected and summarized in a descriptive table. The quality of selected studies was assessed using the PEDro scale. Statistical analysis was conducted to evaluate intergroup differences and changes after the WBV intervention compared to the pre-intervention status. The level of evidence was determined based on the results of meta-analysis (effect size), statistical heterogeneity (I2) and methodological quality (PEDro scale).Results: A total of 859 studies were initially identified through databases with 46 articles meeting all of the inclusion criteria and thus selected for qualitative assessment. Twenty-five studies were included in meta-analysis for quantitative synthesis. In elderly subjects, small but significant improvements in the TUG test (SMD = −0.18; 95% CI: −0.32, −0.04) and the 10MWT (SMD = −0.28; 95% CI: −0.56, −0.01) were found in the WBV groups with a strong level of evidence (I2 = 7%, p = 0.38 and I2 = 22%, p = 0.28, respectively; PEDro scores ≥5/10). However, WBV failed to improve the 6MWT (SMD = 0.37; 95% CI: −0.03, 0.78) and the Tinetti gait scores (SMD = 0.04; 95% CI: −0.23, 0.31) in older adults. In stroke patients, significant improvement in the 6MWT (SMD = 0.33; 95% CI: 0.06, 0.59) was found after WBV interventions, with a strong level of evidence (I2 = 0%, p = 0.58; PEDro score ≥5/10). On the other hand, there was no significant change in the TUG test despite a tendency toward improvement (SMD = −0.29; 95% CI: −0.60, 0.01). Results were inconsistent in COPD patients (I2 = 66%, p = 0.03), leading to a conflicting level of evidence despite a significant improvement with a large effect size (SMD = 0.92; 95% CI: 0.32, 1.51) after WBV treatment. Similarly, the heterogeneous results in the TUG test (I2 = 97%, p < 0.00001) in patients with knee osteoarthrosis make it impossible to draw a conclusion. Still, adding WBV treatment was effective in significantly improving the 6 MWT (SMD = 1.28; 95% CI: 0.57, 1.99), with a strong level of evidence (I2 = 64%, p = 0.06; PEDro score ≥5/10). As in stroke, WBV failed to improve the results of the TUG test in multiple sclerosis patients (SMD = −0.11; 95% CI: −0.64, 0.43). Other outcomes presented moderate or even limited levels of evidence due to the lack of data in some studies or because only one RCT was identified in the review.Conclusions: WBV training can be effective for improving balance and gait speed in the elderly. The intervention is also effective in improving walking performance following stroke and in patients with knee osteoarthrosis. However, no effect was found on gait quality in the elderly or on balance in stroke and multiple sclerosis patients. The results are too heterogenous in COPD to conclude on the effect of the treatment. The results must be taken with caution due to the lack of data in some studies and the methodological heterogeneity in the interventions. Further research is needed to explore the possibility of establishing a standardized protocol targeting gait ability in a wide range of populations