Hold design supports learning and transfer of climbing fluency

Being a discipline with a broad range of genres, rock climbing is an activity where participants seek to generalize the skills they learn in different performance contexts. A training strategy for achieving skill transfer was explored in a group of experienced climbers. Specifically, we tested the effect of practising on three routes, each of the same difficulty, but where handholds supported opportunities for using either a single technical action or multiple actions. Transfer of climbing fluidity in terms of the geometric index of entropy (GIE) of the hip trajectory was then assessed. We expected that learning would be induced on the route where multiple actions were usable. Results revealed that GIE showed a learning effect only when practice was undertaken on a route designed with multiple graspable edges. Practice on the multi-functional route best explains why the participants' successfully generalized climbing fluency under transfer conditions

Prediction of lactate threshold using the modified Conconi test in distance runners

This study aimed to examine the validity of the modified Conconi test (CT) to predict lactate threshold (LT) during running. Twelve distance runners randomly performed the modified CT and the incremental test in which LT was determined directly by measuring blood lactate (BLa). Mean values of heart rate (HR) and running speed (RS) at heart rate deflection point (HRDP) obtained through the modified CT were compared with those at LT. Subsequently, the runners who showed a HRDP in the modified CT performed a 30-min prolonged exercise test (PET) at a RS corresponding to HRDP. During this test, the kinetics of BLa and HR were analyzed to determine whether a steady state in these variables could be attained. We succeeded in identifying HRDP in nine of our runners, whereas the remaining three runners showed entirely linear HR response. In those nine runners, no significant difference was found between HR and RS at HRDP and those at LT. Significant correlation was found between HR at HRDP and HR at LT (r = 0.84, p = 0.005), but RS at HRDP was not significantly correlated with RS at LT (r = 0.63, p = 0.07). All nine runners were able to complete the PET with steady state conditions being achieved for both BLa and HR. In conclusion, these findings indicate that the modified CT has a potential to be used as an alternative method for assessment of LT in distance runners presenting a HRDP

Ecological cognition : expert decision-making behaviour in sport

Expert decision-making can be directly assessed, if sport action is understood as an expression of embedded and embodied cognition. Here, we discuss evidence for this claim, starting with a critical review of research literature on the perceptual-cognitive basis for expertise. In reviewing how performance and underlying processes are conceived and captured in extant sport psychology, we evaluate arguments in favour of a key role for actions in decision-making, situated in a performance environment. Key assumptions of an ecological dynamics perspective are also presented, highlighting how behaviours emerge from the continuous interactions in the performer-environment system. Perception is of affordances; and action, as an expression of cognition, is the realization of an affordance and emerges under constraints. We also discuss the role of knowledge and consciousness in decision-making behaviour. Finally, we elaborate on the specificities of investigating and understanding decision-making in sport from this perspective. Specifically, decision-making concerns the choice of action modes when perceiving an affordance during a course of action, as well as the selection of a particular affordance, amongst many that exist in a landscape in a sport performance environment. We conclude by pointing to some applications for the practice of sport psychology and coaching and identifying avenues for future research

Understanding key constraints and practice design in Rugby Union place kicking : experiential knowledge of professional kickers and experienced coaches

Place kicks present valuable opportunities to score points in Rugby Union, which are typically performed under varying constraints in competitive performance environments. Previous quantitative studies suggest these interacting constraints can influence fluctuations in place kick success. To further the understanding of how fluctuations in place kicking success emerge, our aim was twofold: i) to explore and identify the key constraints that professional place kickers and experienced place kicking coaches perceive to influence the difficulty of a place kick and ii) to understand the level to which current place kicking practice environments represent these key constraints experienced in performance environments. Six professional place kickers and six experienced place kicking coaches were interviewed. Using a deductive thematic analysis, 11 key constraints were identified: individual constraints of expectation for success and fatigue, task constraints of angle and distance to goalposts, environmental constraints of wind, weather, pitch, and crowd, and situational constraints of previous kicking performance, time remaining and current score margin. Place kicking is typically practised individually or with a small number of place kickers in isolation from team sessions. Where possible, coaches should be encouraged to include place kicking in simulated game scenarios during practice to represent key constraints from performance environments. Our study demonstrates how experiential knowledge can enrich the understanding of sport performance and inform the design of practice environments which simulate relevant constraints of competitive performance to enhance skill adaptation of athletes

Emergence of contact injuries in invasion team sports : an ecological dynamics rationale

The incidence of contact injuries in team sports is considerable, and injury mechanisms need to be comprehensively understood to facilitate the adoption of preventive measures. In Association Football, evidence shows that the highest prevalence of contact injuries emerges in one-on-one interactions. However, previous studies have tended to operationally report injury mechanisms in isolation, failing to provide a theoretical rationale to explain how injuries might emerge from interactions between opposing players. In this position paper, we propose an ecological dynamics framework to enhance current understanding of behavioural processes leading to contact injuries in team sports. Based on previous research highlighting the dynamics of performer–environment interactions, contact injuries are proposed to emerge from symmetry-breaking processes during on-field interpersonal interactions among competing players and the ball. Central to this approach is consideration of candidate control parameters that may provide insights on the information sources used by players to reduce risk of contact injuries during performance. Clinically, an ecological dynamics analysis could allow sport practitioners to design training sessions based on selected parameter threshold values as primary and/or secondary preventing measures during training and rehabilitation sessions

Band-edge absorption characteristics of semi-insulating indium phosphide under unified Franz-Keldysh and Einstein models

The foundational Franz-Keldysh effect and Einstein model are applied in this work to characterize semiconductor band-edge absorption—and its departures from ideality. We unify the Franz-Keldysh and Einstein models to fully characterize the field-induced tunneling of photoexcited electrons from degenerate valence bands into the conduction band, with encroachment into the band gap arising as an Urbach tail. Our unified model is implemented for semi-insulating indium phosphide (SI-InP) with strong agreement seen between the theoretical and experimental results for varied photon energies and electric fields

MKEM: a Multi-level Knowledge Emergence Model for mining undiscovered public knowledge

<p>Abstract</p> <p>Background</p> <p>Since Swanson proposed the Undiscovered Public Knowledge (UPK) model, there have been many approaches to uncover UPK by mining the biomedical literature. These earlier works, however, required substantial manual intervention to reduce the number of possible connections and are mainly applied to disease-effect relation. With the advancement in biomedical science, it has become imperative to extract and combine information from multiple disjoint researches, studies and articles to infer new hypotheses and expand knowledge.</p> <p>Methods</p> <p>We propose MKEM, a Multi-level Knowledge Emergence Model, to discover implicit relationships using Natural Language Processing techniques such as Link Grammar and Ontologies such as Unified Medical Language System (UMLS) MetaMap. The contribution of MKEM is as follows: First, we propose a flexible knowledge emergence model to extract implicit relationships across different levels such as molecular level for gene and protein and Phenomic level for disease and treatment. Second, we employ MetaMap for tagging biological concepts. Third, we provide an empirical and systematic approach to discover novel relationships.</p> <p>Results</p> <p>We applied our system on 5000 abstracts downloaded from PubMed database. We performed the performance evaluation as a gold standard is not yet available. Our system performed with a good precision and recall and we generated 24 hypotheses.</p> <p>Conclusions</p> <p>Our experiments show that MKEM is a powerful tool to discover hidden relationships residing in extracted entities that were represented by our Substance-Effect-Process-Disease-Body Part (SEPDB) model. </p

Predicting volleyball serve-reception at group level

In a group-serve-reception task, how does serve-reception become effective? We addressed "who" receives/passes the ball, what task-related variables predict action mode selection and whether the action mode selected was associated with reception efficacy. In 182 serve-receptions we tracked the ball and the receivers' heads with two video-cameras to generate 3D world-coordinates reconstructions. We defined receivers' reception-areas based on Voronoi diagrams (VD). Our analyses of the data showed that this approach was accurate in describing "who" receives the serve in 95.05% of the times. To predict action mode selection, we used variables related to: serve kinematics, receiver's movement and on-court positioning, the relation between receiver and his closest partner, and interactions between receiver-ball and receiver-target. Serve's higher initial velocities together with higher maximum height, as well as smaller longitudinal distances between receiver and target increased the chances for the use of the overhand pass. Conversely, decreasing alignment of the receiver with the ball and the target increased the chances of using the underhand-lateral pass. Finally, the use of the underhand-lateral pass was associated with lower quality receptions. Behavioural variability's relevance for serve-reception training is discussed