Clustering performances in the NBA according to players’ anthropometric attributes and playing experience

The aim of this study was: (i) to group basketball players into similar clusters based on a combination of anthropometric characteristics and playing experience; and (ii) explore the distribution of players (included starters and non-starters) from different levels of teams within the obtained clusters. The game-related statistics from 699 regular season balanced games were analyzed using a two-step cluster model and a discriminant analysis. The clustering process allowed identifying five different player profiles: Top height and weight (HW) with low experience, TopHW-LowE; Middle HW with middle experience, MiddleHW-MiddleE; Middle HW with top experience, MiddleHW-TopE; Low HW with low experience, LowHW-LowE; Low HW with middle experience, LowHW-MiddleE. Discriminant analysis showed that TopHW-LowE group was highlighted by two-point field goals made and missed, offensive and defensive rebounds, blocks, and personal fouls; whereas the LowHW-LowE group made fewest passes and touches. The players from weaker teams were mostly distributed in LowHW-LowE group, whereas players from stronger teams were mainly grouped in LowHW-MiddleE group; and players that participated in the finals were allocated in the MiddleHW-MiddleE group. These results provide alternative references for basketball staff concerning the process of evaluating performance.     

Influence of physical fitness on cognitive and academic performance in adolescents: A systematic review from 2005–2015

Background: The aim of this systematic review was to investigate the association of different components of physical fitness on cognitive performance (CP) and academic performance (AP) in adolescents, taking into account potential confounders. Method: Studies were identified in four databases (Pubmed, SportDiscus, Web of Science, and ProQuest) from January 2005 through to January 2015. A total of 21 articles met the inclusion criteria. Results: 8 studies showed association between physical fitness and CP, and 11 studies with AP. Cardiorespiratory fitness, speed-agility, motor coordination, and perceptual-motor skill are the highest measures associated with CP and AP. However, the findings on strength and flexibility are unclear. Finally, 62% of the 21 studies used confounders. The most controlled confounder were socioeconomic status, fatness, pubertal status, sex, and age. Conclusion: Fitness is associated with higher CP and AP. More research is needed in order to understand the causes of the differential effect of physical fitness components on CP and AP.     

Do previous sports experiences influence the effect of an enrichment programme in basketball skills?

The aim of this study was to examine the effect of an enrichment programme in motor, technical and tactical basketball skills, when accounting for the age of youth sport specialisation. Seventy-six college students (age: M = 20.4, SD = 1.9) were allocated according to three different paths: (i) non-structured (n = 14), (ii) early specialisation (n = 34), and (iii) late specialisation (n = 28), according to information previously provided by the participants about the quantity and type of sporting activities performed throughout their sporting careers. Then, the participants of each path were randomly distributed across control and experimental groups. Variables under study included agility, technical skills circuit, as well as tactical actions performed in a 4-on-4 full-court basketball game. The results indicated improvements in the early and late specialisation paths namely in the experimental training groups. However, the late specialisation path revealed larger benefits, in contrast with the non-structured path, which showed less sensitivity to the enrichment programme, mostly sustained in physical literacy and differential learning. Higher improvements were observed in agility, and also in reducing the number of unsuccessful actions performed during the game. Overall, this study provided evidence of how early sports experiences affect basketball skill acquisition and contribute to adapt to new contexts with motor and technical-tactical challenges. In addition, a path supported by late specialisation might present several advantages in sport performance achievement.     

Polycentric organizing and performance: A contingency model and evidence from megaproject planning in the UK

This study sheds light on polycentric forms of organizing and corresponding performance implications. Organizations with a polycentric architecture supplement their internal hierarchical decision-making structures with egalitarian, local structures in order to encourage collaboration with legally independent stakeholders. We ground our study on the planning stage for four capital-intensive infrastructure development projects (megaprojects) in the UK. We first establish that megaproject planning is carried on by polycentric organizations. We show that in this form of organizing the promoter has decision-making authority over the high-order choices, but shares the authority over the local choices with groups of autonomous stakeholders. We also show how this organizational architecture addresses local disputes and pressures to relax performance targets. Our main contribution is a contingency model that proposes four conditions linking performance to polycentric organizing, whether or not: i) the institutional environment empowers an ‘umpire’ to referee disputes; and ii) the system leader can mobilize substantial slack resources to reconcile conflicting interests. We argue that the four conditions reveal very different classes of managerial problems, and draw implications for practice and policy including but not limited to megaprojects.     

Project risk management and design flexibility: Analysing a case and conditions of complementarity

We explore how risk management and design flexibility interplay in major (infrastructure) projects, using the £4.2bn Terminal 5 project to expand London's Heathrow airport. By juxtaposing these two conceptual frames, we unearth the conditions under which they can be complements for managing the tension between efficiency and effectiveness central to these projects. Building design flexibility - through modular or safeguarded integral architectures - increases adaptability to accommodate evolving requirements which is necessary to attain effectiveness. Efficiency, in turn, demands risk management to deliver the project ‘on time, within budget’. We explain variation in the interplay between the two approaches, highlighting the moderating role of the developer's relationship with the customer. Strong co-operation, particularly in a stable environment, encourages investments in design flexibility. Risk management practices prevail when co-operation breaks down. Another insight is that co-location and continuity of key project staff are themselves inadequate conditions to sustain co-operation.     

From exclusion to inclusion: Collaborative work contributions to more inclusive learning settings

There have been deep changes in societies during the last decade. As a result, schools face new challenges, such as avoiding exclusion by promoting inclusion. In this paper we present the findings of our efforts to use collaborative work as a mediation tool in order to achieve more inclusive learning settings. This work starts from the assumption that learning should be seen as a communicative process. This builds on the ideas of Vygotsky, who stressed the importance of social interactions in the development of complex functions and of working in the zone of proximal development in order to promote children’s development. The study used a critical and ethnographic approach and thus peer interactions were implemented as a daily practice. Data were collected through participant observation (audio and videotaped), questionnaires, tasks inspired in projective techniques, interviews, reports, and sets of materials gathered by the teachers. The findings illuminate the role of collaboration in facilitating more positive attitudes towards academic learning and mathematics, promoting students’ socialisation, their socio-cognitive and affective development, and their school achievement.     

Modelling the relationship between biomechanics and performance of young sprinting swimmers

The aim of this study was to compute a swimming performance confirmatory model based on biomechanical parameters. The sample included 100 young swimmers (overall: 12.3?±?0.74 years; 49 boys: 12.5?±?0.76 years; 51 girls: 12.2?±?0.71 years; both genders in Tanner stages 1–2 by self-report) participating on a regular basis in regional and national-level events. The 100?m freestyle event was chosen as the performance indicator. Anthropometric (arm span), strength (throwing velocity), power output (power to overcome drag), kinematic (swimming velocity) and efficiency (propelling efficiency) parameters were measured and included in the model. The path-flow analysis procedure was used to design and compute the model. The anthropometric parameter (arm span) was excluded in the final model, increasing its goodness-of-fit. The final model included the throw velocity, power output, swimming velocity and propelling efficiency. All links were significant between the parameters included, but the throw velocity–power output. The final model was explained by 69% presenting a reasonable adjustment (model's goodness-of-fit; x²/df?=?3.89). This model shows that strength and power output parameters do play a mediator and meaningful role in the young swimmers’ performance.     

Differential Learning as a Key Training Approach to Improve Creative and Tactical Behavior in Soccer

Purpose: The aim of this study was to identify the effects of a differential-learning program, embedded in small-sided games, on the creative and tactical behavior of youth soccer players. Forty players from under-13 (U13) and under-15 (U15) were allocated into control and experimental groups and were tested using a randomized pretest to posttest design using small-sided games situations. Method: The experimental group participated in a 5-month differential-learning program embodied in small-sided games situations, while the control group participated in a typical small-sided games training program. In-game creativity was assessed through notational analyses of the creative components, and the players’ positional data were used to compute tactical-derived variables. Results: The findings suggested that differential learning facilitated the development of creative components, mainly concerning attempts (U13, small; U15, small), versatility (U13, moderate; U15, small), and originality (U13, unclear; U15, small) of players’ actions. Likewise, the differential-learning approach provided a decrease in fails during the game in both experimental groups (moderate). Moreover, differential learning seemed to favor regularity in pitch-positioning behavior for the distance between players’ dyads (U13, small; U15, small), the distance to the team target (U13, moderate; U15, small), and the distance to the opponent target (U13, moderate; U15, small). Conclusions: The differential-learning program stressed creative and positional behavior in both age groups with a distinct magnitude of effects, with the U13 players demonstrating higher improvements over the U15 players. Overall, these findings confirmed that the technical variability promoted by differential learning nurtures regularity of positioning behavior.     

Effect of wetted surface area on friction,pressure, wave and total drag of a kayak

Using theoretical principles, the components of drag (friction D _F, pressure D _PR and wave D _W) of a single-seat kayak were analysed. The purpose was to examine the effect of changes in wetted surface area due to changes in kayaker’s weight and the relative contribution of D _F, D _PR and D _W to the total passive drag as function of velocity. The total passive drag values were based on experimental data collected in a single-seat kayak. Three different kayaker simulated weights were tested – 65, 75 and 85 kg. D _F was the drag component that contributed the greatest percentage (between 60 and 68% at 5.56 m/s the top velocity tested) to the total passive drag for all the velocities tested and simulated weights. D _W was the most affected by the increase in kayaker’s simulated weight, mainly when comparing 65/75 to 85 kg. Results support the importance of a kayak design selection that minimises the kayak’s drag for the individual weight of the kayaker. Also, the results suggest that the path for better hydrodynamic kayak performance should seek changes that can reduce D _F, D _PR and D _W with D _F offering the most potential to reduce passive drag.