THE EFFECT OF A COMMON COACHING CUE ON BODY KINEMATICS IN THE TENNIS SERVE

The objective of this study was to quantify the kinematic changes promoted by instructing players to implement a common coaching constraint, an arabesque finish position, in the tennis serve. A 10 camera 500 Hz 3D VICON MX motion analysis system recorded the service action of 8 elite junior players as they performed 3 normal serves and 3 serves with an arabesque finish. The arabesque finish promoted greater frontal plane trunk range of motion and angular velocity (shoulder over shoulder rotation) as well as increased leg drive; variables established as important in the development of serve speed. Instructing players to finish in an arabesque position can therefore be considered an effective way to elicit the desired kinematic change, and is consequently an effective instructional cue

REDEFINING SPATIAL CONSISTENCY IN THE BALL TOSS OF THE PROFESSIONAL FEMALE TENNIS SERVE

The objective of this study was to quantify the three-dimensional spatial variability of the ball toss in the female tennis serve and interpret its practical implications. A 500Hz optical motion capture system recorded the ball toss trajectory while eight professional female players performed flat 1st serves. The anteroposterior and lateral variability of ball location was smaller at ball zenith compared with impact. The impact height was the most consistent aspect of the ball toss. Given these findings, the prevailing coaching drills that emphasize consistency appear too stringent. Players should be granted more liberal constraints when rehearsing the ball toss and ball toss drills should retain a racket-ball impact component (as opposed to rehearsing the ball toss in isolation) to refine a consistent impact height

HOW IMPORTANT IS PERCEPTION-ACTION COUPLING IN THE TENNIS SERVE?

The purpose of this study was to examine how removing visual feedback affects ball and racket kinematics in the tennis serve. A 10-camera 500 Hz VICON MX motion analysis system recorded the service actions of 8 elite junior players as they performed three serves with eyes open and three serves with eyes closed. Removal of vision resulted in considerable differences in both racket and ball kinematics, and the interaction between the two. The results highlight that the service action is not pre-programmed, and that visual feedback is critical to the temporospatial regulation of the service action. These findings suggest that coaches need to be aware of the implications of removing perception-action couplings, and ensure that the drills that they prescribe represent the action being trained

Perceiving movement patterns: Implications for skill evaluation, correction and development

Skill practitioners such as coaches, judges, and rehabilitation specialists rely heavily on the visual observation of movement to analyse performance, concomitantly performers of movement rely heavily on kinaesthetic sensitivity to produce movements of desired precision. The observation of movement errors (by coaches or therapists) and the correction of movement errors (by performers or patients) depend on fundamentally different perceptual systems that may differ in their sensitivity, units of control and trainability. This paper first examines the skill of perceiving fundamental movement characteristics and patterns (i.e., movement kinematics) by reviewing sport expertise literature that has investigated the capabilities of both expert performers and expert observers. Important expertise related differences in visual perceptual skill are discussed with a focus on perceptual and motor contributions to perceptual skill. Theories related to the perception of others movement patterns such as common coding are reviewed with a focus on implications for skill practitioners. Limitations in the current visual observation literature are considered, in particular the need to more directly examine the perceptual capabilities of skill practitioners to reliably differentiate changes in kinematics. The critical parallel issue of the kinaesthetic sensitivity of the patient or athlete is also reviewed, highlighting the need to know the magnitude of the differences between visual and kinaesthetic sensitivities for changes in movement kinematics in order to understand some of the challenges involved in matching detection of movement pattern errors to correction of these errors. Future research directions are discussed; particularly key methodological issues which may help directly establish perceptual sensitivity

A framework for human microbiome research

A variety of microbial communities and their genes (the microbiome) exist throughout the human body, with fundamental roles in human health and disease. The National Institutes of Health (NIH)-funded Human Microbiome Project Consortium has established a population-scale framework to develop metagenomic protocols, resulting in a broad range of quality-controlled resources and data including standardized methods for creating, processing and interpreting distinct types of high-throughput metagenomic data available to the scientific community. Here we present resources from a population of 242 healthy adults sampled at 15 or 18 body sites up to three times, which have generated 5,177 microbial taxonomic profiles from 16S ribosomal RNA genes and over 3.5 terabases of metagenomic sequence so far. In parallel, approximately 800 reference strains isolated from the human body have been sequenced. Collectively, these data represent the largest resource describing the abundance and variety of the human microbiome, while providing a framework for current and future studies

Structure, function and diversity of the healthy human microbiome

Author Posting. © The Authors, 2012. This article is posted here by permission of Nature Publishing Group. The definitive version was published in Nature 486 (2012): 207-214, doi:10.1038/nature11234.Studies of the human microbiome have revealed that even healthy individuals differ remarkably in the microbes that occupy habitats such as the gut, skin and vagina. Much of this diversity remains unexplained, although diet, environment, host genetics and early microbial exposure have all been implicated. Accordingly, to characterize the ecology of human-associated microbial communities, the Human Microbiome Project has analysed the largest cohort and set of distinct, clinically relevant body habitats so far. We found the diversity and abundance of each habitat’s signature microbes to vary widely even among healthy subjects, with strong niche specialization both within and among individuals. The project encountered an estimated 81–99% of the genera, enzyme families and community configurations occupied by the healthy Western microbiome. Metagenomic carriage of metabolic pathways was stable among individuals despite variation in community structure, and ethnic/racial background proved to be one of the strongest associations of both pathways and microbes with clinical metadata. These results thus delineate the range of structural and functional configurations normal in the microbial communities of a healthy population, enabling future characterization of the epidemiology, ecology and translational applications of the human microbiome.This research was supported in part by National Institutes of Health grants U54HG004969 to B.W.B.; U54HG003273 to R.A.G.; U54HG004973 to R.A.G., S.K.H. and J.F.P.; U54HG003067 to E.S.Lander; U54AI084844 to K.E.N.; N01AI30071 to R.L.Strausberg; U54HG004968 to G.M.W.; U01HG004866 to O.R.W.; U54HG003079 to R.K.W.; R01HG005969 to C.H.; R01HG004872 to R.K.; R01HG004885 to M.P.; R01HG005975 to P.D.S.; R01HG004908 to Y.Y.; R01HG004900 to M.K.Cho and P. Sankar; R01HG005171 to D.E.H.; R01HG004853 to A.L.M.; R01HG004856 to R.R.; R01HG004877 to R.R.S. and R.F.; R01HG005172 to P. Spicer.; R01HG004857 to M.P.; R01HG004906 to T.M.S.; R21HG005811 to E.A.V.; M.J.B. was supported by UH2AR057506; G.A.B. was supported by UH2AI083263 and UH3AI083263 (G.A.B., C. N. Cornelissen, L. K. Eaves and J. F. Strauss); S.M.H. was supported by UH3DK083993 (V. B. Young, E. B. Chang, F. Meyer, T. M. S., M. L. Sogin, J. M. Tiedje); K.P.R. was supported by UH2DK083990 (J. V.); J.A.S. and H.H.K. were supported by UH2AR057504 and UH3AR057504 (J.A.S.); DP2OD001500 to K.M.A.; N01HG62088 to the Coriell Institute for Medical Research; U01DE016937 to F.E.D.; S.K.H. was supported by RC1DE0202098 and R01DE021574 (S.K.H. and H. Li); J.I. was supported by R21CA139193 (J.I. and D. S. Michaud); K.P.L. was supported by P30DE020751 (D. J. Smith); Army Research Office grant W911NF-11-1-0473 to C.H.; National Science Foundation grants NSF DBI-1053486 to C.H. and NSF IIS-0812111 to M.P.; The Office of Science of the US Department of Energy under Contract No. DE-AC02-05CH11231 for P.S. C.; LANL Laboratory-Directed Research and Development grant 20100034DR and the US Defense Threat Reduction Agency grants B104153I and B084531I to P.S.C.; Research Foundation - Flanders (FWO) grant to K.F. and J.Raes; R.K. is an HHMI Early Career Scientist; Gordon&BettyMoore Foundation funding and institutional funding fromthe J. David Gladstone Institutes to K.S.P.; A.M.S. was supported by fellowships provided by the Rackham Graduate School and the NIH Molecular Mechanisms in Microbial Pathogenesis Training Grant T32AI007528; a Crohn’s and Colitis Foundation of Canada Grant in Aid of Research to E.A.V.; 2010 IBM Faculty Award to K.C.W.; analysis of the HMPdata was performed using National Energy Research Scientific Computing resources, the BluBioU Computational Resource at Rice University

Increasing frailty is associated with higher prevalence and reduced recognition of delirium in older hospitalised inpatients: results of a multi-centre study

Purpose: Delirium is a neuropsychiatric disorder delineated by an acute change in cognition, attention, and consciousness. It is common, particularly in older adults, but poorly recognised. Frailty is the accumulation of deficits conferring an increased risk of adverse outcomes. We set out to determine how severity of frailty, as measured using the CFS, affected delirium rates, and recognition in hospitalised older people in the United Kingdom. Methods: Adults over 65 years were included in an observational multi-centre audit across UK hospitals, two prospective rounds, and one retrospective note review. Clinical Frailty Scale (CFS), delirium status, and 30-day outcomes were recorded. Results: The overall prevalence of delirium was 16.3% (483). Patients with delirium were more frail than patients without delirium (median CFS 6 vs 4). The risk of delirium was greater with increasing frailty [OR 2.9 (1.8–4.6) in CFS 4 vs 1–3; OR 12.4 (6.2–24.5) in CFS 8 vs 1–3]. Higher CFS was associated with reduced recognition of delirium (OR of 0.7 (0.3–1.9) in CFS 4 compared to 0.2 (0.1–0.7) in CFS 8). These risks were both independent of age and dementia. Conclusion: We have demonstrated an incremental increase in risk of delirium with increasing frailty. This has important clinical implications, suggesting that frailty may provide a more nuanced measure of vulnerability to delirium and poor outcomes. However, the most frail patients are least likely to have their delirium diagnosed and there is a significant lack of research into the underlying pathophysiology of both of these common geriatric syndromes

% View time split by phase.sav

Percentage of total trial spend viewing each of the 9 locations