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Revised approach to the role of fatigue in anterior cruciate ligament injury prevention

BACKGROUND: Causes of anterior cruciate ligament (ACL) injuries are multifactorial. Anterior cruciate ligament injury prevention should thus be approached from a multifactorial perspective as well. Training to resist fatigue is an underestimated aspect of prevention programs given that the presence of fatigue may play a crucial role in sustaining an ACL injury.OBJECTIVES:The primary objective of this literature review was to summarize research findings relating to the kinematic and kinetic effects of fatigue on single-leg landing tasks through a systematic review and meta-analysis. Other objectives were to critically appraise current approaches to examine the effects of fatigue together with elucidating and proposing an optimized approach for measuring the role of fatigue in ACL injury prevention.METHODS:A systematic literature search was conducted in the databases PubMed (1978-November 2017), CINAHL (1992-November 2017), and EMBASE (1973-November 2017). The inclusion criteria were: (1) full text, (2) published in English, German, or Dutch, (3) healthy subjects, (4) average age ≥ 18 years, (5) single-leg jump landing task, (6) evaluation of the kinematics and/or kinetics of the lower extremities before and after a fatigue protocol, and (7) presentation of numerical kinematic and/or kinetic data. Participants included healthy subjects who underwent a fatigue protocol and in whom the effects of pre- and post-fatigue on three-dimensional lower extremity kinematic and kinetics were compared. Methods of data collection, patient selection, blinding, prevention of verification bias, and study design were independently assessed.RESULTS:Twenty studies were included, in which four types of single-leg tasks were examined: the single-leg drop vertical jump, the single-leg drop landing, the single-leg hop for distance, and sidestep cutting. Fatigue seemed to mostly affect initial contact (decreased angles post-fatigue) and peak (increased angles post-fatigue) hip and knee flexion. Sagittal plane variables at initial contact were mostly affected under the single-leg hop for distance and sidestep cutting conditions whilst peak angles were affected during the single-leg drop jump.CONCLUSIONS:Training to resist fatigue is an underestimated aspect of prevention programs given that the presence of fatigue may play a crucial role in sustaining an ACL injury. Considering the small number of variables affected after fatigue, the question arises whether the same fatigue pathways are affected by the fatigue protocols used in the included laboratory studies as are experienced on the sports field.

Multinational web uses and gratifications: Measuring the Social Impact of Online Participation Across National Boundaries

This paper will describe the rationale and findings from a multinational study of online uses and gratifications conducted in the United States, Korea, and the Netherlands in spring 2003. A survey research method of study was conducted using a questionnaire developed in three languages and was presented to approximately 400 respondents in each country via the Web. Web uses and gratifications were analyzed cross-nationally in a comparative fashion and focused on the perceived involvement in different types of on-line communities. Findings indicate that demographic characteristics, cultural values, and Internet connection type emerged as critical factors that explain why the same technology is adopted differently. The analyses identified seven major gratifications sought by users in each country: social support, surveillance & advice, learning, entertainment, escape, fame & aesthetic, and respect. Although the Internet is a global medium, in general, web use is more local and regional. Evidence of media use and cultural values reported by country and online community supports the hypothesis of a technological convergence between societies, not a cultural convergence.

Reference values for isometric muscle force among workers for the Netherlands

BACKGROUND: Muscle force is important for daily life and sports and can be measured with a handheld dynamometer. Reference values are employed to quantify a subject's muscle force. It is not unambiguous whether reference values can be generalized to other populations. Objectives in this study were; first to confirm the reliability of the utilization of hand-held dynamometers for isometric strength measurement; second to determine reference values for a population of Dutch workers; third to compare these values with those of a USA population.METHODS: 462 Healthy working subjects (259 male, 203 female) were included in this study. Their age ranged from 20 to 60 years with a mean (sd) of 41 (11) years. Muscle force values from elbow flexion and extension, knee flexion and extension, and shoulder abduction were measured with the break method using a MicroFet 2 hand-held dynamometer. Reliability was analyzed by calculating ICC's and limits of agreement. Muscle force expressed in Newton, means, and confidence intervals were determined for males and females in age groups ranging from twenty to sixty years old. Regression equations and explained variances were calculated from weight, height, age, and gender. The mean values and 95% CI were compared to the results from other studies.RESULTS: Reliability was good; the ICC ranged between 0.83 to 0.94. The explained variance ranged from 0.25 to 0.51. Comparison of data for the Dutch population mean muscle force values with those from the USA revealed important differences between muscle force reference values for the American and Dutch populations.CONCLUSIONS: Muscle force measurements demonstrate a sound reliability. Reference values and regressions equations are made available for the Dutch population. Comparison with other studies indicates that reference values differ between countries.

Reisverslag India 2009

Verslag van een bezoek in mei 2009 aan India als onderdeel van een delegatie van KPN. In een week werden bezoeken gebracht aan 7 IT leveranciers van KPN, 3 universiteiten en waren er gesprekken met diverse andere partijen. Daarbij zijn de steden Mumbai, Pune, Bangalore en Chennai aangedaan. Dit verslag geeft een beeld van de stand van zaken op het gebied van IT & Business Process Outsourcing in India. REP-09-01

Monitoring of sport injuries in young elite soccer players

Creating social impact with side-events

All over the world, sport events are seen as significant tools for creating positive social impact. This is understandable, as sport events have the power to attract enthusiastic participants, volunteers and to reach large audiences of visitors and followers via (social) media. Outbursts of excitement, pleasure and feelings of camaraderie are experienced among millions of people in the case of mega events. Still, a fairly large section of the population does not care that much for sports. Some may experience road blocks, litter and noise disturbance from the events. Sport events generally require investments, often from local or national authorities. Concerned citizens rightfully point at alternative usage of public money (e.g. schools, health care). Thrills and excitement are good things, but does that warrant public money being spent on? Or is there a broader social significance of sport events? Can sport events help alleviate societal issues (like cohesion, inequality and non-participation), do they generate a social impact beyond what spectators experience during the event? In this report the authors have aimed to describe the state of play as regards the evidence for the occurrence of a social impact from sport events and the strategies that are required to enhance social impact from sport events. For the report, an extensive scan of the literature was performed and input was collected from a key group of international experts.