Free kick goals in football: an unlikely success between failure and embarrassment

We develop and use a numerical model to investigate the window of opportunity of free kicks in association football. The planar multibody forward dynamics model comprises a two segment leg model with joint actuations, a football, a wall and the turf. Contact mechanics is defined to model the impact of the foot and the ball’s interaction with the different elements in the environment. The optimum kick is determined using the global optimization algorithm differential evolution, requiring millions of kick simulations. The sensitivity of various solutions to parameter perturbation is investigated. It is concluded that toe kicks are theoretically superior to instep kicks, but are difficult to perform reliably. The results also show that small perturbations in parameters can lead to embarrassingly failed kicks.     

A topography of free kicks in soccer

ABSTRACT

This study investigates the spatial relationship of performance variables for soccer free kicks. In order to suggest ways in which players might optimise their performance, we collected data from free kicks (<35 m to goal line) of two German Bundesliga seasons (2013/14, 2014/15) (n = 1624). In the analysis, we applied the ISO-map approach using colour gradients to visualise the mean values of a variable on a 2D-map of the pitch. Additionally, variograms were used to describe the degree of spatial dependence of the free kick variables. Results show that DENSITY, TYPE OF PLAY, PLAYERS IN WALL, DISTANCE TO WALL and RULE VIOLATION were strongly spatially dependent. Centrality and proximity to the goal increased the variables PLAYERS IN WALL, RULE VIOLATIONS and INTERRUPTION TIME, and the ratio of goals scored increased from 5.9% (central far) to 10.9% (central near). In 70.9% of the shots, players preferred a switched laterality, which did not result in a higher success rate. Furthermore, there was no statistical advantage for the defensive team when DISTANCE TO WALL was below 9.15 m or when there was a RULE VIOLATION. Crosses had a success rate (i.e., first controlled ball contact after the cross) of 20.8%. Played with natural laterality, they were 5% more successful than with switched laterality. Crosses from the right side outside the penalty box were 10% more successful than from the left side. Therefore, it might be worthwhile practising the defence of balls coming from this side.     

Predicting Achievement Goals in Two Different Academic Contexts: A longitudinal study

The relative contribution is examined of epistemological beliefs and implicit theories of intelligence to students' adoption of mastery, performance‐approach and performance‐avoidance goals in two different academic contexts, business administration and teacher education, in the short as well as the long term. The results showed that epistemological beliefs about the speed of knowledge acquisition predicted achievement goals. Students who believed that learning occurs quickly or not at all were less likely to adopt mastery goals and more likely to adopt performance‐avoidance goals. In addition, students who believed in stable and given knowledge were less likely to adopt mastery goals. Differences in predictive patterns across the two contexts concerned the prediction of performance‐approach goals and gender differences in goal adoption. Epistemological beliefs played a more important role in goal adoption than implicit theories of intelligence.     

Infant vocalizing and phenotypic outcomes in autism: Evidence from the first 2 years

Infant vocalizations are early-emerging communicative markers shown to be atypical in autism spectrum disorder (ASD), but few longitudinal, prospective studies exist. In this study, 23,850 infant vocalizations from infants at low (LR)- and high (HR)-risk for ASD (HR-ASD = 23, female = 3; HR-Neg = 35, female = 13; LR = 32, female = 10; 80% White; collected from 2007 to 2017 near Philadelphia) were analyzed at 6, 12, and 24 months. At 12 months, HR-ASD infants produced fewer vocalizations than HR-Neg infants. From 6 to 24 months, HR-Neg infants demonstrated steeper vocalization growth compared to HR-ASD and LR infants. Finally, among HR infants, vocalizing at 12 months was associated with language, social phenotype, and diagnosis at age 2. Infant vocalizing is an objective behavioral marker that could facilitate earlier detection of ASD.     

Primary teachers’ experiences with weekly education outside the classroom during a year

The aim of the present study was through semi-structured interviews to explore udeskole teacher’s perceptions of motivational factors and challenges while teaching regularly outside the classroom on a weekly basis during a year. Six females and two male udeskole teachers participated and answered an interview guide containing five themes about their motivations, student relations, teaching experiences, challenges and recognition. Udeskole was perceived to have substantial potentials to improve both academic learning and life skills and ‘the common third’, i.e. teacher–pupil relations, was mentioned as a value added to the indoor teaching. Health and safety issues were not perceived as barriers.     

Rater strategies for reaching agreement on pupil text quality

Novice members of a Norwegian national rater panel tasked with assessing Year 8 pupils’ written texts were studied during three successive preparation sessions (2011–2012). The purpose was to investigate how the raters successfully make use of different decision-making strategies in an assessment situation where pre-set criteria and standards give a rather strict framework. The data sources were the raters’ pair assessment dialogues. The analysis shows that the raters use a ‘shared standards strategy’, but when reaching agreement on text quality they also seem to make very good use of assessment strategies related to their work as writing teachers. Moreover, asymmetries in knowledge and participation among raters contribute to creating an image of writing assessment as a challenging hermeneutic practice. It is suggested that future rater preparation would gain from being attentive to the internalised assessment practices teachers bring to the fore when working as raters.     

Introducing teachers to new semiotic tools for writing instruction and writing assessment: consequences for students’ writing proficiency

This article reports consequences for student writing quality based on a long-term professional learning project. Project teachers, representing all school subjects in grades 3–7, were presented with a writing construct, ‘Wheel of Writing’, and norms of expectation for writing proficiency. Participating teachers used the writing construct and norms as a basis for writing instruction and writing assessment. The project was conducted in 24 schools across Norway. 3088 students from 20 project schools participated. Two hundred and thirty three students from 4 schools were used as a comparison group. The investigation showed that students in primary school improved their writing quality significantly. Students in lower secondary school did not. However, there was substantial variation in writing quality effects between schools, classes, and individual students. For instance at a number of schools, project students from lower secondary school improved their writing quality significantly. The article discusses potential explanations of the effects.     

Kinematic differences of elite and high-performance tennis players in the cross court and down the line forehand

This study identified and compared the full body kinematics of different skill levels in the forehand groundstroke when balls were hit cross court and down the line. Forty-three three-dimensional retro-reflective marker trajectories of six elite and seven high-performance players were recorded using an eight-camera 400 Hz, Vicon motion analysis system. The six highest horizontal velocity forehands with reliable kinematics of all participants were analysed for each specific situation (a total of 156 analysed shots). Significant differences (p < 0.01) and large effect sizes were observed between elite and high-performance players in linear velocity of the shoulder (2.0 vs. 1.2 m/s), angular velocity of the pelvis (295 vs. 168 °/s), and angular velocity of the upper trunk (453 vs. 292 °/s) at impact. The elite group showed a tendency towards higher racquet velocities at impact (p < 0.05). No significant differences were found in angular displacement of the racquet, hip alignment, or shoulder alignment at the completion of the backswing; nor did angular displacement vary significantly at impact. Irrespective of the group, different shoulder, hip, and racquet angles were found at impact, depending on the situation. The results should assist coaches when striving to improve their players' forehand.