Unsteady flow phenomena in human undulatory swimming: a numerical approach

The undulatory underwater sequence is one of the most important phases in competitive swimming. An understanding of the recurrent vortex dynamics around the human body and their generation could therefore be used to improve swimming techniques. In order to produce a dynamic model, we applied human joint kinematics to three-dimensional (3D) body scans of a female swimmer. The flow around this dynamic model was then calculated using computational fluid dynamics with the aid of moving 3D meshes. Evaluation of the numerical results delivered by the various motion cycles identified characteristic vortex structures for each of the cycles, which exhibited increasing intensity and drag influence. At maximum thrust, drag forces appear to be 12 times higher than those of a passive gliding swimmer. As far as we know, this is the first disclosure of vortex rings merging into vortex tubes in the wake after vortex recapturing. All unsteady structures were visualized using a modified Q-criterion also incorporated into our methods. At the very least, our approach is likely to be suited to further studies examining swimmers engaging in undulatory swimming during training or competition.     

Anticipatory postural adjustments during cutting manoeuvres in football and their consequences for knee injury risk

Abstract

Anticipatory postural adjustments (APAs), i.e. preparatory positioning of the head, the trunk and the foot, are essential to initiate cutting manoeuvres during football games. The aim of the present study was to determine how APA strategies during cutting manoeuvres are influenced by a reduction of the time available to prepare the movement.

Thirteen football players performed different cutting tasks, with directions of cutting either known prior to the task or indicated by a light signal occurring 850, 600 or 500 ms before ground contact.

With less time available to prepare the cutting manoeuvre, the head was less orientated towards the cutting direction (P = 0.033) and the trunk was even more rotated in the opposite direction (P = 0.002), while the foot placement was not significantly influenced. Moreover, the induced higher lateral trunk flexion correlated with the increased knee abduction moment (r = 0.41; P = 0.009).

Increasing lateral trunk flexion is the main strategy used to successfully perform a cutting manoeuvre when less time is available to prepare the movement. However, higher lateral trunk flexion was associated with an increased knee abduction moment and therefore an increased knee injury risk. Reducing lateral trunk flexion during cutting manoeuvres should be part of training programs seeking the optimisation of APAs.     

The polygenic profile of Russian football players

Abstract

Research concerned with predictors of talent in football has highlighted a number of potentially important and partially inherited measures such as body size, anaerobic power, aerobic capacity, agility, psychological profile, game intelligence and susceptibility to injuries. Genotyping for performance-associated DNA polymorphisms at an early age could be useful in predicting later success in football. The aim of the study was to investigate individually and in combination the association of common gene polymorphisms with football player’s status. A total of 246 Russian football players and 872 controls were genotyped for 8 gene polymorphisms, which were previously reported to be associated with athlete status. Four alleles (ACE D, ACTN3 Arg577, PPARA rs4253778 C and UCP2 55Val) were first identified, showing discrete associations with football player’s status. Next, we determined the total genotype score (TGS, from the accumulated combination of the 4 polymorphisms, with a maximum value of 100 for the theoretically optimal polygenic score) in athletes and controls. The mean TGS was significantly higher in football players (52.0 (17.6) vs. 41.3 (15.5); P < 0.0001) than in controls. These data suggest that the likelihood of becoming a football player depends on the carriage of a high number of “favourable” gene variants.     

Historiography,Cultures of Remembrance and Tradition in German Sport

Erinnerungskultur (culture of remembrance) is a widely discussed notion in German historiography. First, the meaning of Erinnerungskultur, including the specific role of academic historiography of sport, is described and explained with respect to sport and sport historiography. One main objective is to reveal the diversity of cultures of sport history and the specific obligations of academic historiography. Second, the actors of sport memories and/or Traditionspflege (heritage) are characterised, and, third, some controversial and perennial debates that permeate German sports history are explained and interpreted, especially that of Carl Diem, internationally known as ‘Mister Olympics’ of 1936. All in all, the paper provides an overview of the mainstreams, cultures and politics of history in Germany with respect to sport.     

THE SOCIAL PATTERN OF THE LENGTH OF FULL‐TIME EDUCATION IN ESSEX

Based on the work of Barron (1966) and Hudson (1966), the hypothesis is set up that science pupils are more obsessional than arts pupils. This is confirmed on a substantial sample of sixth‐formers. However, it also appears that the possession of obsessional traits is a hindrance to performance in the sciences. The educational implications of these findings are discussed.     

UNIVERSITY‐BASED ADULT DAY CARE CENTER FOR RESEARCH AND TRAINING: DESIGN,FUNDING, AND PROGRAMMATIC ISSUES

In the early 1980s, the College of Human Resources at Virginia Polytechnic Institute and State University began a visioning process to plan its educational agenda for the 21st century. One of the more pressing issues targeted for educational intervention was community‐based long‐term care. Ten years later, a licensed, Medicaid‐certified adult day health center is fully operational on the university campus, providing a myriad of research, teaching, and public service opportunities for faculty and students. Center design, funding, and programmatic issues are discussed.