Elite football on artificial turf versus natural grass: movement patterns, technical standards, and player impressions

The aim of the present study was to examine the movement patterns, ball skills, and the impressions of Swedish elite football players during competitive games on artificial turf and natural grass. Time - motion analyses (36 observations) and technical analyses (16 team observations) were performed and 72 male and 21 female players completed a questionnaire. No differences were observed between artificial turf and natural grass in terms of total distance covered (mean 10.19 km, s = 0.19 vs. 10.33 km, s = 0.23), high-intensity running (1.86 km, s = 0.10 vs. 1.87 km, s = 0.14), number of sprints (21, s = 1 vs. 22, s = 2), standing tackles (10, s = 1 vs. 11, s = 1) or headers per game (8, s = 1 vs. 8, s = 1), whereas there were fewer sliding tackles (P < 0.05) on artificial turf than natural grass (2.1, s = 0.5 vs. 4.3, s = 0.6). There were more short passes (218, s = 14 vs. 167, s = 12) and midfield-to-midfield passes (148, s = 11 vs. 107, s = 8) (both P < 0.05) on artificial turf than natural grass. On a scale of 0-10, where 0 = "better than", 5 = "equal to", and 10 = "worse than", the male players reported a negative overall impression (8.3, s = 0.2), poorer ball control (7.3, s = 0.3), and greater physical effort (7.2, s = 0.2) on artificial turf than natural grass. In conclusion, the running activities and technical standard were similar during games on artificial turf and natural grass. However, fewer sliding tackles and more short passes were performed during games on artificial turf. The observed change in playing style could partly explain the male players' negative impression of artificial turf.     

Special populations: the female player and the youth player

Females and youth are frequently described as "special" populations in football literature, but together these two populations outnumber male players. What makes females "special" is that they tend to eat less when training and competing than their male counterparts, leading to lower intakes of energy, carbohydrate, and some nutrients. Youth football players are special in regard to energy and nutrient requirements to promote growth and development, as well as to fuel sport. There is limited research on the dietary habits of these two populations, but the available literature suggests that many female and youth players need to increase carbohydrate intake, increase fluid intake, and develop dietary habits to sustain the demands of training and competition.     

Knowledge production in a constructed field: reflections on comparative and international education

Adopting Maria Manzon’s theoretical framework, which draws on Foucault and proposes that comparative education as an academic field is socially constructed, I suggest that the field is neither stable nor well defined. To demonstrate this, I conduct a content analysis of the Comparative Education Review, using Klaus Krippendorff’s methodological framework to study comparative and international education (CIE) researchers’ understanding of the national—and of their related knowledge production in the field. Many comparativists express interests in multiple countries, and their knowledge production takes the form of individual country studies. The countries are habitually studied using a “problem approach” focusing on one specific aspect of the country under investigation and using an associated social science methodology deemed appropriate. Few comparativists are making explicit use of or reference to any methodology that is unique to comparative education. Efforts to catalog and systematize CIE research have demonstrated that the field is becoming so inclusive that it hardly is distinguishable from educational studies as a whole. Hence, I suggest that instead of speaking about unifying features of the field, it may be more relevant to speak about frequent elements, such as a focus on the national, and a knowledge production characterized by the academic practitioner who desires to improve the education systems studied. A third frequent element may be the focus on educational development, thus justifying the label of “comparative, international, and development education.” One challenge of the field is its dependence on Western social science discourses, which may be marginalizing other voices.     

Topic variability and criteria in interpretational history teaching

This paper studies the teacher perceived applicability of historical topics for interpretational history teaching and the criteria teachers use to evaluate this applicability. For this study, 15 expert history teachers in the Netherlands striving for interpretational history teaching were purposefully selected. Teachers were asked to mention historical topics using a ranking task technique to rank topics in order of applicability and to elaborate on how the topics were ranked. The results showed a large variation in perceived applicability among topics, both within and between teachers. Eight different topic-applicability criteria were discerned in the teachers’ elaborations: (1) topic knowledge; (2) topic affinity; (3) topic constructedness; (4) topic deconstructability; (5) topic abstractedness; (6) topic sensitivity; (7) topic materials; and (8) topic inclusion in the history curriculum. We found that teachers tended to judge topics as applicable for interpretational history teaching partly depending on the degree of ‘canonised interpretativity’ in lesson materials and the curriculum, and to the degree to which they belonged to ‘cold’ (morally neutral) or ‘hot’ (morally sensitive) history. A theoretical implication of the findings is that interpretational history teaching is topic-dependent. Teachers can be supported to teach history as interpretation by structured pedagogies.     

Social Media in the Funeral Industry: On the Digitization of Grief

This article explores how innovations in the funeral industry borrow from the technological affordances, commercial logics, cultural norms, and affective registers of social media platforms. Based on ethnographic research of funeral industry conventions, we analyze examples of funeral planning tools, funeral service mediation, and digital memorialization products. We consider how these products aim to capture forms of data, affect, and value as part of the funeral industry’s efforts to shore up their historically intermediary relevance in the face of potential “disruption” from technological innovation, and threats of marginalization posed by shifting norms of networked grieving and commemoration in digital culture     

Energy turnover during 24 hours and 6 days of adventure racing

Abstract

Energy turnover was assessed in two conditions of mixed ultra-endurance exercise. In Study 1, energy expenditure and intake were measured in nine males in a laboratory over 24 h. In Study 2, energy expenditure was assessed in six males during an 800-km Adventure race (mean race time 152.5 h). Individual correlations between heart rate and oxygen uptake ([Vdot]O₂) were established during pre-tests when kayaking, cycling, and running. During exercise, energy expenditure was estimated from continuous heart rate recordings. Heart rate and [Vdot]O₂ were measured regularly during fixed cycling work rates to correct energy expenditure for drift in oxygen pulse. Mean energy expenditure was 18,050 ± 2,390 kcal (750 ± 100 kcal · h^?1) and 80,000 ± 18,000 kcal (500 ± 100 kcal · h^?1) in Study 1 and Study 2 respectively, which is higher than previously reported. Energy intake in Study 1 was 8,450 ± 1,160 kcal, resulting in an energy deficit of 9,590 ± 770 kcal. Body mass decreased in Study 1 (?2.3 ± 0.8 kg) but was unchanged in Study 2. Fat mass decreased in Study 2 (?2.3 ± 1.5 kg). In Study 1, muscle glycogen content decreased by only 60%. Adventure racing requires a high energy expenditure, with large inter-individual variation. A large energy deficit is caused by inadequate energy intake, possibly due to suppressed appetite and gastrointestinal problems. The oxygen pulse, comparing start to 12 h of exercise and beyond, increased by 10% and 5% in Study 1 and Study 2 respectively. Hence, estimations of energy expenditure from heart rate recordings should be corrected according to this drift.     

Push-off forces in elite short-track speed skating

This study performed an analysis of the push-off forces of elite-short-track speed skaters using a new designed instrumented short-track speed skate with the aim to improve short-track skating performance. Four different skating strokes were distinguished for short-track speed skaters at speed. The strokes differed in stroke time, force level in both normal and lateral directions, and the centre of pressure (COP) on the blade. Within the homogeneous group of male elite speed skaters (N = 6), diversity of execution of the force patterns in the four phases of skating was evident, while skating at the same velocities. The male participants (N = 6) with a better personal record (PR) kept the COP more to the rear of their blades while hanging into the curve (r = 0.82, p < 0.05), leaving the curve (r = 0.86, p < 0.05), and entering the straight (r = 0.76, p < 0.10). Furthermore, the male skaters with a better PR showed a trend of a lower lateral peak force while entering the curve (r = 0.74, p < 0.10). Females showed a trend towards applying higher body weight normalised lateral forces than the males, while skating at imposed lower velocities.     

Fatigue and illness in athletes

Adequate nutrition before, during, and after training and competition is a key element to maintaining health. During both sprint and endurance exercise, the availability of glycogen is fundamental to performance and any deficit will lead to early fatigue. In addition, strategies to offset the negative effects of the products of metabolism are presented. Although nutritional strategies can attenuate the immunosuppressive effects of exercise, there remains a period of susceptibility to infection after a hard exercise session and when this is repeated without sufficient recovery an athlete can enter a period of "overtraining" during which performance deteriorates. The aetiology and identification of this state is not clear and some current ideas are discussed. Finally, gastrointestinal problems during running can negate any training benefits and we propose some suggestions to reduce this problem.     

The use of recovery methods post-exercise

Competitive soccer engages many of the body's systems to a major extent. The musculoskeletal, nervous, immune and metabolic systems are stressed to a point where recovery strategies post-exercise become influential in preparing for the next match. Intense activity at a 7-day training camp causes participants to experience lowered concentrations of non-killer cells and T-helper cells. Two consecutive games in 24 h produce disturbances in the testosterone-cortisol ratio. When competitive schedules are congested, the recovery process should be optimized for performance capabilities to be restored to normal as soon as possible. There is evidence that glycogen stores are reduced near to depletion at the end of a soccer game and that a diet high in carbohydrates can aid recovery. Water alone is not the best means of restoring body fluids, since carbohydrate-electrolyte drinks display better intestinal absorption and reduce urine output. Some relief from muscle soreness may be achieved by means of a warm-down. Deep-water running regimens can replace conventional physical training in the days after competition. Massage, cryotherapy and alternative therapies have not been shown to be consistently effective. It is concluded that optimizing recovery post-exercise depends on a combination of factors that incorporate a consideration of individual differences and lifestyle factors. The procedures to facilitate recovery processes should start immediately the game or training finishes. Match administrators and tournament planners should consider the stressful consequences for players in periods of congested fixtures and alleviate the physiological strain as far as possible by allowing 72 h between competitive games. This frequency of competition is unlikely to be sustainable in the long term.     

Five Strategies for Optimizing Instructional Materials: Instructor- and Learner-Managed Cognitive Load

Educational Psychology Review - Researchers of cognitive load theory and the cognitive theory of multimedia learning have identified several strategies to optimize instructional materials. In this...