Fatigue increases ankle sprain risk in badminton players: A biomechanical study     

Alexis Herbaut  Julien Delannoy 《Journal of sports sciences》2020,38(13):1560-1565

ABSTRACT

Ankle sprains are the most common injury in regular badminton players and usually occur at the end of a match or training. The purpose of the present study was to examine the influence of fatigue produced by badminton practice on the lower limb biomechanics of badminton players. It was hypothesized that fatigue induces ankle kinematic and lower leg muscle activity changes which may increase the risk of ankle sprain. Ankle kinematics, ankle kinetics and muscles activities of 17 regular badminton players were recorded during lateral jumps before and after an intense badminton practice session. Post-fatigue, ankle inversion at foot strike and peak ankle inversion increased (+2.6°, p = 0.003 and +2.5°, p = 0.005, respectively). EMG pre-activation within 100 ms before foot landing significantly decreased after fatigue for soleus (?23.4%, p = 0.031), gastrocnemius lateralis (?12.2%, p = 0.035), gastrocnemius medialis (?23.3%, p = 0.047) and peroneus brevis (?17.4%, p = 0.036). These results demonstrate impaired biomechanics of badminton players when fatigue increases, which may cause a greater risk of experiencing an ankle sprain injury.  相似文献   

Primary Care and Laboratory Medicine—Frequently Asked Questions     

Joseph Lopez 《Indian journal of clinical biochemistry : IJCB》2012,27(1):105-106

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Do karate fighters use situational probability information to improve decision-making performance during on-mat tasks?     

Nicolas Milazzo  Damian Farrow  Alexis Ruffault  Jean F. Fournier 《Journal of sports sciences》2016,34(16):1547-1556

This study examined the contribution of situational probability information to the perceptual and cognitive processes underlying decision-making behaviour during in situ Karate performance. Experts and novices were required to make decisions about various attacks in different fight scenarios. The order in which the fight situations were presented was modified in order to provide advanced probability information and identify whether fighters were able to use the latter information to make better decisions. Specifically, one of the attacks was repeated every four actions. Results revealed that experts were more accurate and faster than their less skilled counterparts to block and counterattack the opponent. The experts picked up the occurrence of the attack pattern after the fifth repetition whereas novices did not. This enabled experts to improve decision time and decision accuracy. Findings suggest that such superiority could stem from the perceptual and cognitive skills possessed by the experts, thus giving them the opportunity to recognise a situation more easily. This was reinforced by gaze behaviour which demonstrated that experts used a more efficient search strategy involving fewer fixations of longer duration on a lesser number of areas relative to the novices. Moreover, experts generated more refined karate-specific knowledge structures compared with the novices.  相似文献   

Equity in groupwork: the social process of creating justice in a science classroom     

Patterson  Alexis D. 《Cultural Studies of Science Education》2019,14(2):361-381

Cultural Studies of Science Education - Over the last few decades, there has been an international focus on productive talk in science classrooms, requiring teachers to use more dialogic practices...  相似文献   

The influence of shoe drop on the kinematics and kinetics of children tennis players     

Alexis Herbaut  Pascale Chavet  Maxime Roux  Nils Guéguen  Christophe Gillet  Franck Barbier 《European Journal of Sport Science》2016,16(8):1121-1129

This study investigated the immediate effects of reducing the shoe drop (i.e. the difference between the heel and the forefoot height) on the kinematics and kinetics of the lower extremities of children tennis players performing a tennis-specific movement. Thirteen children tennis players performed a series of simulated open stance forehands wearing 3 pairs of shoes differing only in the drop: 0 (D0), 6 (D6) and the control condition of 12?mm (D12). Two embedded forceplates and a motion capture system were used to analyse the ground reaction forces and ankle and knee joint angles and moments of the leading lower limb. In D6 compared with D12, the peak impact force was reduced by 24% (p?=?.004) and the ankle was less dorsiflexed at foot strike (p?=?.037). In D0 compared with D12, the peak impact force was reduced by 17% (p?=?.049), the ankle was less dorsiflexed at foot strike (p?=?.045) and the knee was more flexed at foot strike (p?=?.007). In addition, 4 out of 13 participants (31%) presented a forefoot strike pattern for some of the trials in D0. No difference was observed across shoe conditions for the peak knee extensor moment (p?=?.658) or the peak ankle plantarflexor moment (p?=?.071). The results provide preliminary data supporting the hypothesis that for children tennis players, using a 6-mm lower shoe drop might reduce heel impact forces and thus limit potentially impact-related injuries.  相似文献   

How New Caledonian crows solve novel foraging problems and what it means for cumulative culture     

Corina J. Logan  Alexis J. Breen  Alex H. Taylor  Russell D. Gray  William J. E. Hoppitt 《Learning & behavior》2016,44(1):18-28

New Caledonian crows make and use tools, and tool types vary over geographic landscapes. Social learning may explain the variation in tool design, but it is unknown to what degree social learning accounts for the maintenance of these designs. Indeed, little is known about the mechanisms these crows use to obtain information from others, despite the question’s importance in understanding whether tool behavior is transmitted via social, genetic, or environmental means. For social transmission to account for tool-type variation, copying must utilize a mechanism that is action specific (e.g., pushing left vs. right) as well as context specific (e.g., pushing a particular object vs. any object). To determine whether crows can copy a demonstrator’s actions as well as the contexts in which they occur, we conducted a diffusion experiment using a novel foraging task. We used a nontool task to eliminate any confounds introduced by individual differences in their prior tool experience. Two groups had demonstrators (trained in isolation on different options of a four-option task, including a two-action option) and one group did not. We found that crows socially learn about context: After observers see a demonstrator interact with the task, they are more likely to interact with the same parts of the task. In contrast, observers did not copy the demonstrator’s specific actions. Our results suggest it is unlikely that observing tool-making behavior transmits tool types. We suggest it is possible that tool types are transmitted when crows copy the physical form of the tools they encounter.  相似文献   

Early Identification and Intervention: Head Start's Response to Mental Health Challenges     

Michael L. Lopez  Louisa B. Tarullo  Steven R. Forness  Cheryl A. Boyce 《Early education and development》2000,11(3):265-282

Serving low-income children from birth to age five and their families, Head Start is a primary venue for identification and intervention in the area of child mental health. However, recent research has demonstrated that the knowledge base regarding prevalence, developmental course, and predictive power of child mental health problems is lacking for young children in general and low-income, diverse populations in particular. Head Start's agency-level data is often discrepant from both national estimates and small, intensive studies of similar populations, perhaps for reasons related to availability of community services and professional staff, as well as concerns about stigmatization. Following on recent expert recommendations, new collaborative Federal initiatives are underway to increase our understanding of the types, trajectories, and treatments of mental health problems affecting the vulnerable children served by Head Start. The paper concludes with a call to action for the field in the area of young children's mental health.  相似文献   

Incentive learning and the motivational control of instrumental performance by thirst     

Matias Lopez  Bernard Balleine  Anthony Dickinson 《Learning & behavior》1992,20(4):322-328

The role of incentive learning in instrumental performance following a shift in the degree of water deprivation was analyzed in three experiments. In Experiments 1A and IB, rats trained to perform an instrumental action reinforced with either sucrose or maltodextrin solutions when in a high-deprivation state were subsequently shifted to a low-deprivation state and tested in extinction. This within-state shift in water deprivation reduced instrumental performance only when the animals had been exposed to the reinforcer in the low-deprivation state prior to instrumental training. In Experiment 2, a concurrent training procedure was used to assess whether the change in the value of the reinforcer brought about by preexposurewas mediated by the contingency between the instrumental action and the reinforcer. Preexposure to the reinforcer under the low-deprivation state produced a selective reduction of the performance of the action upon which it was contingent during training when testing was conducted in extinction following a shift from the high- to the low-deprivation state. These experiments provide evidence that animals have to learn about the incentive value of a reinforcer in a particular motivational state through exposure to the reinforcer in that state.  相似文献   

Supporting child and family resilience in the face of political violence: Evidence from a home visit parenting program     

Jane Leer  Florencia Lopez Boo  Savannah Norman 《Child development》2023,94(5):1222-1238

Political violence affects more than 25% of children globally, yet little is known about how to support positive adaptation among conflict-affected children. Using a sample of 3797 Nicaraguan child-caregiver dyads (M_AgeTime1 = 1.5 years, M_AgeTime2 = 5.9 years; 51% male), this registered report used a novel quasi-experimental approach to examine how exposure to political violence relates to child and caregiver outcomes, and to test three policy-relevant moderators: participation in a large-scale home visit parenting program, household economic disruption, and media exposure. Results revealed positive associations between political violence and harsh discipline practices (0.33 SD), but there was no evidence that political violence affected children's behavior, caregiver depressive symptoms, or responsive parenting practices, and there was no evidence of moderation.  相似文献   

“Things your history teacher won't teach you: Science edition”: Black women science teachers as anti-racist teachers     

Alexis D. Riley  Felicia Moore Mensah 《科学教学研究杂志》2024,61(4):809-840

Marginalized communities cannot and do not have decontextualized experiences with how socioscientific issues, such as exposure to COVID-19 as frontline essential workers, high Black infant mortality rates, air pollution leading to respiratory problems, and other issues, affect their communities. As PreK-12 science teachers and teacher educators strive to dismantle oppressive practices in their classrooms and curriculum, it would be helpful to learn from Black women science teachers who have been engaging in anti-racist practices before the racial awakenings of Summer 2020. In this study, three different virtual focus groups, or Sista Circles, were conducted with 18 Black women secondary science teachers. Ranging from 1 to 22 years of experience, Black women teachers across the country and international participants in Canada and Qatar participated in the Sista Circles. From intersectional qualitative analysis and narrative inquiry, the findings of the study reveal that Black women science teachers enact anti-racist science teaching by bringing something new to the community; using NGSS standards within the context of the community; teaching at the intersection of history, culture, and science learning and teaching; and building critical consciousness in the science classroom. Furthermore, the findings of the study have implications for the use of anti-racist frameworks within the context of science education that were authentically the practices of the Black women in the study. This study offers insights into how the critical consciousness of Black women teachers can be represented in the science classroom even in times of nonsupport from peers and administration. The power and necessity of Black women teachers are paramount in science classrooms specifically because of the neutral, apolitical ways science teaching has been approached in the past. The narratives and stories shared here exemplify how Black women science teachers transform science teaching and learning by displaying various acts of Criticality.  相似文献