Optimizing segmental movement in the jumping header in soccer

This study looks at segmental movements in the jumping header from an optimization viewpoint. Investigations on the header so far have focused on head restriction in the movement but have not clarified how and to what extent body segments influence the performance of the skill. In the present study a biomechanical model was used to analyze the jumping header in simulated competition to give a clear picture of an optimized header. Skilled soccer players headed balls at speeds of 13 m x s(-1) the results indicated that the head moves as a free non-restricted segment in the jumping header and should be allowed to do so, even though much soccer literature says otherwise to prevent injuries. The arm movement showed individual characteristics and gave no general advantages in optimizing ball speed after impact in the header The movement of the legs was, on the other hand, the single most important factor in the skill. Therefore, coaches and players shouldfocus on developing muscle strength in the stomach, back and pelvis and should put no restrictions on head and arm movement to optimize the jumping header.     

Close Strangers or Strange Friends? The London Olympics and Anglo-Norwegian Sports Relations in a Historical Perspective

This article studies similarities and disparities between the two nations England and Norway as they could be observed before and during the London 2012 Olympics, and discuss them in the historical perspective of geopolitical and sportive relations. The main perspective is how these relations have been seen and experienced from Norway. The article also studies whether the London Olympics of 2012 did present new forms of relationships between the two geographical neighbours. The article discusses the role of ball games, preferably team handball at the 2012 Games, as one example of where sporting interests differ. The article reflects upon these matters in a historical context. It builds upon traditional historical methods, document and media analysis. It also looks at the 2012 London Olympics against the background of the former London Games of 1908 and 1948, and the overall historical sports relations between England, ‘land of sport’ and a small country like Norway, who generally has been on the receiving end of these interchanges. Such asymmetric relationships invite to a critical use of perspectives like cultural imperialism and post-colonialism. The article discusses whether such perspectives can be fruitful also when one discusses matters between the so-called First World nations. As the title of the article indicates, Norway and England are both close, politically and culturally, while also being strangers to one another, e.g. in parts of the sports culture. The 2012 Olympics seemed to reinforce this impression.     

Foreign direct investment in industrial research and development: A study of German MNCs

This paper reports on the international research and development (R&D) investments of German multinational corporations (MNCs). Based on a detailed empirical survey of laboratory sites established by 49 German MNCs, we examine (i) the level and pace of R&D internationalization, (ii) the motivations and mandates of overseas R&D laboratories, as well as (iii) the strength of the laboratories’ internal and external ties. Participating firms account for about 46% of all German enterprises with international R&D activities and approximately 66% of the nation's privately funded R&D expenditures in 1999. The findings indicate that the timing and organization of German owned overseas R&D investments more closely resemble Japanese or French than US or Swedish firms. Furthermore, in line with prior studies, German MNCs increasingly invest in international R&D for resource as opposed to market-seeking motives. The paper also finds significant differences with regard to the laboratory's mission and its geographical location on one hand, and its internal and external embeddedness, on the other.     

Tribute to Dr Jacques Rogge: muscle activity and fatigue during hiking in Olympic dinghy sailing

‘A tribute to Dr J. Rogge’ aims to systematically review muscle activity and muscle fatigue during sustained submaximal quasi-isometric knee extension exercise (hiking) related to Olympic dinghy sailing as a tribute to Dr Rogge’s merits in the world of sports. Dr Jacques Rogge is not only the former President of the International Olympic Committee, he was also an orthopaedic surgeon and a keen sailor, competing at three Olympic Games. In 1972, in fulfilment of the requirements for the degree of Master in Sports Medicine, he was the first who studied a sailors’ muscle activity by means of invasive needle electromyography (EMG) during a specific sailing technique (hiking) on a self-constructed sailing ergometer. Hiking is a bilateral and multi-joint submaximal quasi-isometric movement which dinghy sailors use to optimize boat speed and to prevent the boat from capsizing. Large stresses are generated in the anterior muscles that cross the knee and hip joint, mainly employing the quadriceps at an intensity of 30–40% maximal voluntary contraction (MVC), sometimes exceeding 100% MVC. Better sailing level is partially determined by a lower rate of neuromuscular fatigue during hiking and for ≈60% predicted by a higher maximal isometric quadriceps strength. Although useful in exercise testing, prediction of hiking endurance capacity based on the changes in surface EMG in thigh and trunk muscles during a hiking maintenance task is not reliable. This could probably be explained by the varying exercise intensity and joint angles, and the great number of muscles and joints involved in hiking.

Highlights

• Dr Jacques Rogge, former president of the International Olympic Committee and Olympic Finn sailor, was the first to study muscle activity during sailing using invasive needle EMG to obtain his Master degree in Sports Medicine at the Ghent University.

• Hiking is a critical bilateral and multi-joint movement during dinghy racing, accounting for >60% of the total upwind leg time. Hiking generates large stresses in the anterior muscles that cross the knee and hip joint.

• Hiking is considered as a quasi-isometric bilateral knee extension exercise. Muscle activity measurements during sailing, recorded by means of EMG, show a mean contraction intensity of 30-40% maximal voluntary contraction with peaks exceeding 100%.

• Hiking performance is strongly related to the development of neuromuscular fatigue in the quadriceps muscle. Since maximal strength is an important determinant of neuromuscular fatigue during hiking, combined strength and endurance training should be incorporated in the training program of dinghy sailors.

     

Removal of Organic Acids from Indoor Air in Museum Storage Rooms by Active and Passive Sorption Techniques

ABSTRACT

Adsorbent materials can be used for the removal of organic acids from air in storage rooms with heritage collections. The organic acid removal efficiency of two commercially available activated carbon air-filters were tested in situ in two unoccupied stores with densely packed collections. One filter was designed for outdoor type pollutants (Filter A), while the other was designed for organic acids in indoor air (Filter B). Furthermore, the acetic acid removal efficiency of a desiccant silica gel rotor used for dehumidification was measured in a laboratory at different relative humidity levels. Finally, passive removal of acetic acid by silica gel and unfired clay brick were tested in a chamber, and for clay brick at room level as well. Filter B had the highest removal efficiency. The removal efficiency of both filter types depended on the airflow and the filter performance varied considerably in situ from the values reported from standard laboratory tests. Increasing the filter airflow reduced the removal efficiency from 77% and down to 7% for Filter A, and from 92% to 24% for Filter B. There was almost no effect of active air filtration on the concentration of organic acids when this was measured in the middle and in the corner of the storage rooms away from the ventilation inlets. The desiccant dehumidifier removed 98–100% of the acetic acid from the air, independently of the relative humidity. The desiccant rotor will, however, only be running when there is a need for dehumidification and as a result will only periodically remove pollutants. The high acid removal efficiency by dry silica gel was furthermore demonstrated in a chamber test. A clay brick wall in a test room established a concentration gradient across the room and reduced the concentration of organic acids by 56% compared to close to the emission source.     

User Experiences with Editorial Control in Online Newspaper Comment Fields

This article investigates user experiences with editorial control in online newspaper comment fields following the public backlash against online comments after the 2011 terror attacks in Norway. We analyze data from a survey of online news consumers focusing on experiences and attitudes towards editorial control set against a spectrum between “interventionist” and “noninterventionist” positions. Results indicate that interventionist respondents rate the quality of online comments as poor, whereas noninterventionist respondents have most often experienced being the target of editorial control measures and feel that editorial control has intensified after the terror attacks. We conclude that newspapers should pay attention to the different needs of participants when devising strategies for editorial control. Media professionals should also consider changes to increase the transparency of moderation practices.     

Blurred Boundaries or Conflicting Epistemologies

In this article, I discuss how information activists and journalists in Egypt claimed to acquire knowledge about the world, looking particularly at the period of 2012 and 2013, during which the Supreme Council of the Armed Forces and Mohammed Morsi in turn were leading the country. Taking a point of departure in anthropological fieldwork with information activists and journalists in Egypt, I show that information activists and journalists often had very similar practices and goals, which at times made the boundaries very blurry. Yet I argue that there was a significant distinction between the epistemologies of information activists and journalists. Information activists claimed to acquire knowledge about events from being part of them, whereas journalists claimed to acquire knowledge about events from observing them without taking part. Relatedly, information activists and journalists had significantly different relationships with their audiences.