Vrabas. The Effect of Natural and Artificial Grass on Sprinting Performance in Young Soccer Players

Abstract: The sprint performance on natural and artificial grass of 5 th generation was assessed. Sixty eight young male soccer players, which were divided in two groups according to their age [children (n=36; 12.1±0.5y) and adolescents (n=32; 14.2±0.4y)], performed 30-m sprint tests with and without handling the ball on natural and artificial grass. The performance was recorded during 0-10m, 10-30m, and 0-30m running distances. It was found that children were significantly faster during 0-10m running distance on the artificial compared to natural grass when handling the ball while adolescents revealed no differences in sprint performance between the surfaces irrespectively of the ball condition. In running distances 10-30m and 0-30m, children were significant faster in the artificial compared to the natural grass either with or without ball, while the adolescents were significantly faster in the artificial grass only without handling the ball. Children run faster on artificial than natural grass while adolescent soccer players are faster in artificial grass when they do not have to handle the ball. It is clear that children should be more careful when play soccer on artificial grass because the ball is moving faster and greater skill is needed in order to avoid injuries

Vitalism in Early Modern Medical and Philosophical Thought

Vitalism is a notoriously deceptive term. It is very often defined as the view, in biology, in early modern medicine and differently, in early modern philosophy, that living beings differ from the rest of the physical universe due to their possessing an additional ‘life-force’, ‘vital principle’, ‘entelechy’, enormon or élan vital. Such definitions most often have an explicit pejorative dimension: vitalism is a primitive or archaic view, that has somehow survived the emergence of modern science (the latter being defined in many different ways, from demystified Cartesian reductionism to experimental medicine, biochemistry or genetics: Cimino and Duchesneau eds. 1997, Normandin and Wolfe eds. 2013). Such dismissive definitions of vitalism are meant to dispense with argument or analysis. Curiously, the term has gained some popularity in English-language scholarship on early modern philosophy in the past few decades, where it is used without any pejorative dimension, to refer to a kind of ‘active matter’ view, in which matter is not reducible to the (mechanistic) properties of size, shape and motion, possessing instead some internal dynamism or activity (see e.g. James 1999, Boyle 2018, Borcherding forthcoming). The latter meaning is close to what the Cambridge Platonist Ralph Cudworth termed ‘hylozoism’, namely the attribution of life, agency or mind to matter, and he implicitly targeted several figures I shall mention here, notably Margaret Cavendish and Francis Glisson, for holding this view. However, one point I shall make in this entry is that when vitalism first appears by name, and as a self-designation, in the Montpellier School (associated with the Faculty of Medicine at the University of Montpellier, in the second half of the eighteenth century; thus vitalisme appears first, followed shortly thereafter by Vitalismus in German, with ‘vitalism’ appearing in English publications only in the early nineteenth century: Toepfer 2011), it is quite different from both the more ‘supernatural’ view described above – chiefly espoused by its rather obsessive opponents – and from the more neutral, but also de-biologized philosophical view (that of e.g. Cavendish or Conway who are, broadly speaking naturalists). Rather than appealing to a metaphysics of vital force, or of self-organizing matter, this version of vitalism, which I shall refer to as ‘medical vitalism’, seems to be more of a ‘systemic’ theory: an attempt to grasp and describe top-level (‘organizational’, ‘organismic’, ‘holistic’) features of living systems (Wolfe 2017, 2019). In this entry I seek to introduce some periodization in our thinking about early modern (and Enlightenment) vitalism, emphasizing the difference between the seventeenth-century context and that of the following generations – culminating in the ideas of the Montpellier School. This periodization should also function as a kind of taxonomy or at least distinction between some basic types of vitalism. As I discuss in closing, these distinctions can cut across the texts and figures we are dealing with, differently: metaphysical vs. non-metaphysical vitalism, philosophical vs. medical vitalism, medical vs. ‘embryological’ vitalism, and so on. A difference I can only mention but not explore in detail is that the more medically grounded, ‘organismic’ vitalism is significantly post-Cartesian while the more biological/embryological vitalism is, inasmuch as it is a dynamic, self-organizing matter theory, an extension of Renaissance ideas (chymiatry, Galenism and in general theories of medical spirits). I examine successively vitalism’s Renaissance prehistory, its proliferation as ‘vital matter theory’ in seventeenth-century England (in authors such as Cavendish, Conway and Glisson, with brief considerations on Harvey and van Helmont), and its mature expression in eighteenth-century Montpellier (notably with Bordeu and Ménuret de Chambaud)

A New Direction to Athletic Performance: Understanding the Acute and Longitudinal Responses to Backward Running

Backward running (BR) is a form of locomotion that occurs in short bursts during many overground field and court sports. It has also traditionally been used in clinical settings as a method to rehabilitate lower body injuries. Comparisons between BR and forward running (FR) have led to the discovery that both may be generated by the same neural circuitry. Comparisons of the acute responses to FR reveal that BR is characterised by a smaller ratio of braking to propulsive forces, increased step frequency, decreased step length, increased muscle activity and reliance on isometric and concentric muscle actions. These biomechanical differences have been critical in informing recent scientific explorations which have discovered that BR can be used as a method for reducing injury and improving a variety of physical attributes deemed advantageous to sports performance. This includes improved lower body strength and power, decreased injury prevalence and improvements in change of direction performance following BR training. The current findings from research help improve our understanding of BR biomechanics and provide evidence which supports BR as a useful method to improve athlete performance. However, further acute and longitudinal research is needed to better understand the utility of BR in athletic performance programs

Investigating trophic ecology and dietary niche overlap among morphs of Lake Trout in Lake Superior

Four morphs of Lake Trout (Salvelinus namaycush, Walbaum 1792) have been identified in Lake Superior: leans, siscowets, humpers, and redfins. In this comprehensive study, the trophic ecology of Lake Trout morphs were characterized using stomach content, fatty acid, and stable isotope data. Stomach content results indicated a predominately piscivorous diet for leans, siscowets, and redfins, whereas humper diets were comprised of 50% fish and 50% Mysis by mass. Humper and siscowets were most similar in their dietary fatty acid profiles, whereas redfins had the most distinct dietary fatty acid profile. Results from stable isotope analysis revealed some among-morph differences along a pelagic-profundal consumption gradient (34S), but there were no significant differences in trophic position (15N) or basal carbon sources among morphs (13C). Using the recently developed nicheROVER software package, 4-dimensional trophic niches for each morph were quantified using stable isotope ratios (δ13C, δ15N, and δ34S) and fatty acid profiles (30 dietary fatty acids, condensed to one axis). Humpers had the largest 4-dimensional niche regions of all four morphs, and redfins had the smallest. Pairwise probability of overlap among morphs in these four-dimensional niche regions was determined to be < 50% in most cases. Overall, stomach content results indicate that humpers diets were more planktivorous than the other morphs, consistent with previous research. Results of the niche overlap analysis suggests some degree of generalist feeding for all morphs. Better characterization of seasonal variation in diet using tracers that reflect more recent feeding (e.g., fatty acids, stomach contents, and/or stable isotope analyses performed on tissues that turnover more quickly than muscle) are needed to further elucidate among-morph differences and similarities in diet and trophic ecology

The dribbling agility test as a potential tool for evaluating the dribbling skill in young soccer players

The present study examined the construct validity and reliability of a new dribbling agility test (DAT) that incorporates reactive agility and multiple change of direction. To check its’ validity, (a) DAT was performed by four groups (under 10, under 12, under 14 and under 16 yrs) of young soccer players (n = 125 in each group) and (b) a regression analysis was conducted to define the best DAT predictors. The reliability of DAT was assessed with repeated measurements. This test can differentiate the dribbling skill between groups (p &lt; 0.01). Furthermore, 68% of the observed variance in DAT was explained by zigzag dribbling test, Illinois agility test, reaction time and running speed. The test-retest reliability was high in all groups (ICC = 0.77–0.90, p &lt; 0.01). It was concluded that DAT can be a potential tool to evaluate the dribbling performance in young soccer players. © 2018, © 2018 Informa UK Limited, trading as Taylor &amp; Francis Group

Conserving the holobiont

1. Organismal biology has undergone a dramatic paradigm shift in the last decade. The realization that host cells and genes are outnumbered by symbiotic microbial cells and their genes has forced us to rethink our focus on ‘individuals’. It is also becoming increasingly clear that the ecology and biology of animals and plants are intimately connected with their microbial partners. In the context of conserving functioning species, such revelatory insights beg the question—what exactly should we be trying to conserve? 2. Here, we review how an understanding of host–microbe interactions can benefit conservation biology. We propose a way forward for conservation biologists, to gather evidence of the potential effects of changes to plant and animal microbiomes, and to incorporate the holobiont concept into applied conservation practice. 3. In humans, microbes influence physiology, health, behaviour and psychology. In animals and plants, microbes similarly influence critically important components of health, communication and (in animals) behaviour. Together, the animal or plant and all of its associated micro-organisms are termed the holobiont. 4. At the same time, humans are now the strongest evolutionary force on the planet, causing global change at unprecedented scale. We know that microbial diversity in humans has been compromised in urban societies, with a growing list of consequences for health and function. While we still have limited evidence for similar effects in plants and animals, anthropogenic factors that affect diversity are also likely to affect animal and plant microbiomes, with similar associated effects on host function and health. 5. Microbiome research is still in its relative infancy, particularly in its application to plants and animals, yet the tools are becoming more widely available and affordable. Forward-looking conservation biologists could harness such tools and apply them to the study of plant and animal microbiomes with the goal of understanding which microbiota might be required to ensure future viability of conserved host populations. 6. For now, the precautionary principle applies. We suggest that, to meaningfully and effectively conserve a species, we must also consider how to conserve the bacteria, viruses, fungi and other symbionts intimately associated with that macro-organism

Variation of aerobic performance indices of professional elite soccer players during the annual macrocycle

BACKGROUND: The purpose of the present study was to examine the variation of aerobic performance parameters of elite Greek soccer players. METHODS: In the study participated twenty-four (24) male professional soccer players (age: 24.3±4.3 years, height: 180.3±3.8 cm and mass: 77.4±6.1 kg), who competed at the top level of the Greek National Championship. Four measurements regarding aerobic parameters were conducted during the annual training cycle (preseason, start of the season, end of the first championship round and end of the season). RESULTS: The ANOVA analysis showed that maximum oxygen uptake (VO2max) was significantly increased after the completion of the preseason and continued to increase until the end of the first round of the Championship. In contrast, a decline was observed towards the end of the season. The velocity to maximum oxygen uptake (vVO2max) and the velocity parameter in respiratory threshold were significantly increased at the end of the preseason and the end of the first round, while the parameters were differentiated at the end of the season. The lactate concentration showed no significant changes during the four measurements. CONCLUSIONS: A systematic observation of players’ performance, especially recording parameters such as VO2max, during the annual training cycle, could provide the necessary feedback for both trainers and players in order to increase team performance. © 2019 EDIZIONI MINERVA MEDIC