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Entropy and Sport

David M Corbett, Alice J Sweeting, Sam Robertson
In team-sport, physical and skilled output is often described via aggregate parameters including total distance and number of skilled involvements. However, the degree to which these output change throughout a team-sport match, as a function of time, is relatively unknown. This study aimed to identify and describe segments of physical and skilled output in team-sport matches with an example in Australian Football. The relationship between the number of change points and level of similarity was also quantified...
February 12, 2019: Journal of Sports Sciences
David J Harris, Samuel J Vine, Mark R Wilson
Achieving a state of flow is associated with positive experiences and improved sporting performance (Jackson & Csikszentmihalyi, 1999). Focused attention is a fundamental component of the flow experience, but to date there has been little investigation of whether attention plays a causal role in creating flow, or is a product of it. Consequently, this study aimed to test the effect of an attentional focus manipulation on flow and performance in a simulated driving task. It was predicted that an external focus would lead to improved visuomotor control, greater flow experience and improved performance...
December 27, 2018: European Journal of Sport Science
William Johnston, Martin O'Reilly, Ciara Duignan, Mairead Liston, Rod McLoughlin, Garrett F Coughlan, Brian Caulfield
BACKGROUND: Concussion is one of the most common sports-related injuries, with little understood about the modifiable and nonmodifiable risk factors. Researchers have yet to evaluate the association between modifiable sensorimotor function variables and concussive injury. PURPOSE: To investigate the association between dynamic balance performance, a discrete measure of sensorimotor function, and concussive injuries. STUDY DESIGN: Cohort study (diagnosis); Level of evidence, 3...
December 3, 2018: American Journal of Sports Medicine
Mark Walsh, Eric Slattery, Arden McMath, Ronald Cox, Joshua Haworth
BACKGROUND: Balance and postural control are integral to training and sport performance. Demands on posture are contextual and vary in different ways depending on the specific physical activity. RESEARCH QUESTION: The purpose of this study was to examine the possibility that sustained exposure to environmental constraints, through specific sport participation, might lead to a persistent modification of postural control. METHODS: Double and single-leg postural sway were compared between ice hockey players, American football players and physically active college students...
October 2018: Gait & Posture
Gerard Moras, Bruno Fernández-Valdés, Jairo Vázquez-Guerrero, Julio Tous-Fajardo, Juliana Exel, Jaime Sampaio
OBJECTIVES: This study described the variability in acceleration during a resistance training task, performed in horizontal inertial flywheels without (NOBALL) or with the constraint of catching and throwing a rugby ball (BALL). DESIGN AND METHODS: Twelve elite rugby players (mean±SD: age 25.6±3.0years, height 1.82±0.07m, weight 94.0±9.9kg) performed a resistance training task in both conditions (NOBALL AND BALL). Players had five minutes of a standardized warm-up, followed by two series of six repetitions of both conditions: at the first three repetitions the intensity was progressively increased while the last three were performed at maximal voluntary effort...
December 2018: Journal of Science and Medicine in Sport
Michael Buchecker, Erich Müller, Stefan Wegenkittl, Gerold Sattlecker, Thomas Stöggl
This study evaluated the short- and long-term effects of unstable shoes (US) on the structure/shape of variability in gait. Therefore, sample entropy (SEn) values of centre of mass velocity (vCOM) signals in medio-lateral (ML), anterior-posterior (AP) and vertical (VT) direction were computed for 12 sport students during walking with US and flat shoes (FS) before and after a 10-week accommodation period. Statistical analysis included two-way repeated-measures ANOVA followed by post hoc tests where appropriate (α = 0...
August 2018: Human Movement Science
Leonardo Lamas, Rene Drezner, Guilherme Otranto, Junior Barrera
The aim of this study was to define a method for evaluating a player's decisions during a game based on the success probability of his actions and for analyzing the player strategy inferred from game actions. There were developed formal definitions of i) the stochastic process of player decisions in game situations and ii) the inference process of player strategy based on his game decisions. The method was applied to the context of soccer goalkeepers. A model of goalkeeper positioning, with geometric parameters and solutions to optimize his position based on the ball position and trajectory, was developed...
2018: PloS One
Tamanna T K Munia, Ali Haider, Charles Schneider, Mark Romanick, Reza Fazel-Rezai
The neurocognitive sequelae of a sport-related concussion and its management are poorly defined. Detecting deficits are vital in making a decision about the treatment plan as it can persist one year or more following a brain injury. The reliability of traditional cognitive assessment tools is debatable, and thus attention has turned to assessments based on electroencephalogram (EEG) to evaluate subtle post-concussive alterations. In this study, we calculated neurocognitive deficits combining EEG analysis with three standard post-concussive assessment tools...
December 8, 2017: Scientific Reports
Ana Ramos, Patrícia Coutinho, Pedro Silva, Keith Davids, Isabel Mesquita
Variability analysis has been used to understand how competitive constraints shape different behaviours in team sports. In this study, we analysed and compared variability of tactical performance indices in players within complex I at two different competitive levels in volleyball. We also examined whether variability was influenced by set type and period. Eight matches from the 2012 Olympics competition and from the Portuguese national league in the 2014-2015 season were analysed (1496 rallies). Variability of setting conditions, attack zone, attack tempo and block opposition was assessed using Shannon entropy measures...
May 2017: European Journal of Sport Science
Marcel Ausloos, Roy Cerqueti
A mere hyperbolic law, like the Zipf's law power function, is often inadequate to describe rank-size relationships. An alternative theoretical distribution is proposed based on theoretical physics arguments starting from the Yule-Simon distribution. A modeling is proposed leading to a universal form. A theoretical suggestion for the "best (or optimal) distribution", is provided through an entropy argument. The ranking of areas through the number of cities in various countries and some sport competition ranking serves for the present illustrations...
2016: PloS One
Arrani Senthinathan, Lynda M Mainwaring, Michael Hutchison
OBJECTIVE: To assess heart rate variability (HRV) in athletes with concussion across three phases of recovery. DESIGN: A prospective matched control group design included the collection of HRV and symptoms measured by the Rivermead Post-Concussion Questionnaire. These measures were taken at 3 phases of recovery [(1) symptomatic; (2). asymptomatic; and (3) one-week after return-to-play (RTP)]. The same protocol was completed by noninjured athletes. SETTING: Interuniversity sports teams at a single institution...
May 2017: Clinical Journal of Sport Medicine: Official Journal of the Canadian Academy of Sport Medicine
Jaclyn B Caccese, Thomas A Buckley, Thomas W Kaminski
The Balance Error Scoring System (BESS) is often used for sport-related concussion balance assessment. However, moderate intratester and intertester reliability may cause low initial sensitivity, suggesting that a more objective balance assessment method is needed. The MobileMat BESS was designed for objective BESS scoring, but the outcome measures must be validated with reliable balance measures. Thus, the purpose of this investigation was to compare MobileMat BESS scores to linear and nonlinear measures of balance...
August 2016: Journal of Applied Biomechanics
Jonathan A N Fisher, Stanley Huang, Meijun Ye, Marjan Nabili, W Bryan Wilent, Victor Krauthamer, Matthew R Myers, Cristin G Welle
Rapid detection and diagnosis of a traumatic brain injury (TBI) can significantly improve the prognosis for recovery. Helmet-mounted sensors that detect impact severity based on measurements of acceleration or pressure show promise for aiding triage and transport decisions in active, field environments such as professional sports or military combat. The detected signals, however, report on the mechanics of an impact rather than directly indicating the presence and severity of an injury. We explored the use of cortical somatosensory evoked electroencephalographic potentials (SSEPs) to detect and track, in real-time, neural electrophysiological abnormalities within the first hour following head injury in an animal model...
September 2016: IEEE Transactions on Neural Systems and Rehabilitation Engineering
B Gonçalves, R Marcelino, L Torres-Ronda, C Torrents, J Sampaio
Optimizing collective behaviour helps to increase performance in mutual tasks. In team sports settings, the small-sided games (SSG) have been used as key context tools to stress out the players' awareness about their in-game required behaviours. Research has mostly described these behaviours when confronting teams have the same number of players, disregarding the frequent situations of low and high inequality. This study compared the players' positioning dynamics when manipulating the number of opponents and teammates during professional and amateur football SSG...
July 2016: Journal of Sports Sciences
A Paglietti
For many physical systems at any given temperature, the set of all states where the system's free energy reaches its largest value can be determined from the system's constitutive equations of internal energy and entropy, once a state of that set is known. Such an approach is fraught with complications when applied to a living cell, because the cell's cytosol contains thousands of solutes, and thus thousands of state variables, which makes determination of its state impractical. We show here that, when looking for the maximum energy that the cytosol can store and release, detailed information on cytosol composition is redundant...
2015: Physical Review. E, Statistical, Nonlinear, and Soft Matter Physics
J A Nessler, M Silvas, S Carpenter, S C Newcomer
Surfers often wear wetsuits while paddling in the ocean. This neoprene covering may be beneficial to upper extremity movement by helping to improve proprioceptive acuity, or it may be detrimental by providing increased resistance. The purpose of this study was to evaluate the effects of wearing a wetsuit on muscle activation, upper extremity motion, heart rate, and oxygen consumption during simulated surfboard paddling in the laboratory. Twelve male, recreational surfers performed two paddling trials at a constant workload on a swim bench ergometer both with and without a wetsuit...
2015: PloS One
Kurt H Schütte, Ellen A Maas, Vasileios Exadaktylos, Daniel Berckmans, Rachel E Venter, Benedicte Vanwanseele
Small wireless trunk accelerometers have become a popular approach to unobtrusively quantify human locomotion and provide insights into both gait rehabilitation and sports performance. However, limited evidence exists as to which trunk accelerometry measures are suitable for the purpose of detecting movement compensations while running, and specifically in response to fatigue. The aim of this study was therefore to detect deviations in the dynamic center of mass (CoM) motion due to running-induced fatigue using tri-axial trunk accelerometry...
2015: PloS One
Feifei Chen, Nong Sang, Xiaoqin Kuang, Haitao Gan, Changxin Gao
Recent methods based on midlevel visual concepts have shown promising capabilities in the human action recognition field. Automatically discovering semantic entities such as action parts remains challenging. In this paper, we present a method of automatically discovering distinctive midlevel action parts from video for recognition of human actions. We address this problem by learning and selecting a collection of discriminative and representative action part detectors directly from video data. We initially train a large collection of candidate exemplar-linear discriminant analysis detectors from clusters obtained by clustering spatiotemporal patches in whitened space...
February 1, 2015: Journal of the Optical Society of America. A, Optics, Image Science, and Vision
Douglas W Powell, D S Blaise Williams
UNLABELLED: Athletes are assumed to exhibit better balance than non-athletes; however, few studies have examined the role of different types of sports on balance measures. Two athlete groups that experience divergent sport-specific balance training are stable- (i.e. basketball) and unstable-surface athletes (i.e. surfers). The purpose of this study was to quantify the effect of stable- compared to unstable-surface sports on postural stability. METHODS: Eight non-athletes (NON), eight stable-surface athletes (SSA) and eight unstable-surface athletes (USA) performed five 20-s quiet standing trials while ground reaction forces were recorded...
December 2015: Human Movement Science
Peter Federolf, Payam Zandiyeh, Vinzenz von Tscharner
The center of pressure (COP) movement in studies of postural control reveals a highly regular structure (low entropy) over short time periods and a highly irregular structure over large time scales (high entropy). Entropic half-life (EnHL) is a novel measure that quantifies the time over which short-term temporal correlations in a time series deteriorate to an uncorrelated, random structure. The current study suggested and tested three hypotheses about how characteristics of the neuromuscular postural control system may affect stabilometric EnHL: (H1) control system activity hypothesis: EnHL decreases with increased frequency of control system interventions adjusting COP motion; (H2) abundance of states hypothesis: EnHL decreases with increased number of mechanically equivalent states available to the postural system; and (H3) neurologic process hierarchy hypothesis: EnHL increases if postural control functions shift from the spinal level to the motor cortex...
December 2015: Experimental Brain Research. Experimentelle Hirnforschung. Expérimentation Cérébrale
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