Velocity profiling using inertial sensors for freestyle swimming

The ability to unobtrusively measure velocity in the aquatic environment is a fundamental challenge for engineers and sports scientists and important in assessing the skill level. The aim of this research was to develop a method for velocity profiling in freestyle swimming utilising a purpose-built inertial sensor. Seventeen swimmers with different experience levels participated in this study performing a total of 159 laps in the velocity range from 0.79 to 2.04 m s^?1. Data were collected using a triaxial accelerometer and a tethered velocity meter. The collected acceleration data were filtered using a 0.5 Hz Hamming-windowed FIR filter to remove the gravitational acceleration before the lap velocity profiles were calculated. These calculated lap velocity profiles were then compared with the velocity profiles measured by the velocity meter using Bland–Altman analysis. The scattering follows a normal distribution with a mean skewness of 0.96 ± 0.47 and kurtosis of 2.93 ± 1.12. The results show that an inertial sensor alone can be used to determine a lap velocity profile from single point acceleration records.     

A model of the relationship among sport consumer motives,spectator commitment,and behavioral intentions

The concept of commitment in sport marketing has largely been regarded as unidimensional. In the broader study of organizational behavior, commitment has been studied as a multidimensional construct. The multiple dimensions of commitment construe that one's behavior can be conveyed by different psychological states, comparable to those found to characterize different forms of commitment. The multidimensional perspective appears to yield more detailed and relevant information regarding a consumer's commitment in predicting specific behaviors. In past decades, a variety of researchers in organizational psychology and organizational behavior have investigated the relationship between motivation and commitment in order to better understand the two processes and their impact on behavior. However, there have been few attempts to integrate the two domains in order to demonstrate how motives and commitment combine to influence sport consumer behavior. Accordingly, a model of commitment and its relationship to sport consumer motives (i.e., antecedent) and behavioral intentions (i.e., consequence) is proposed.     

Thinking about the same things differently: Examining perceptions of a non-profit community sport organisation

This paper explores the differing perceptions and identity responses (identification, apathy and disidentification) that potentially exist in relation to one non-profit Community Sport Organisation (CSO), and whether they explain variations in individuals’ existing values and beliefs, sport interest, community identification and views about one organisation's legitimacy. Data were collected using a quantitative online survey (n = 390), then analysed using Confirmatory Factor Analysis (CFA) and Multiple Analysis of Variance (MANOVA) to test three hypotheses investigating whether existing values and beliefs, shared community values, local players, organisational practices and sport interest varied based on perception of organisational image and identity response. Based on the contributions of this study, non-profit CSOs should spend time developing understanding of the key dimensions that make them relevant to constituents and to decipher the values and beliefs that underpin what external audiences expect from organisations. In addition, understanding specifically what a CSO's audience expects is fundamental if the organisation is to be perceived as legitimate in relation to its purpose.     

Baseball

The purpose of this study was to quantify and compare kinematic, temporal, and kinetic characteristics of American and Korean professional pitchers in order to investigate differences in pitching mechanics, performance, and injury risks among two different cultures and populations of baseball pitchers. Eleven American and eight Korean healthy professional baseball pitchers threw multiple fastball pitches off an indoor throwing mound positioned at regulation distance from home plate. A Motion Analysis three‐dimensional automatic digitizing system was used to collect 200 Hz video data from four electronically synchronized cameras. Twenty kinematic, six temporal, and 11 kinetic variables were analyzed at lead foot contact, during the arm cocking and arm acceleration phases, at ball release, and during the arm deceleration phase. A radar gun was used to quantify ball velocity. At lead foot contact, the American pitchers had significantly greater horizontal abduction of the throwing shoulder, while Korean pitchers exhibited significantly greater abduction and external rotation of the throwing shoulder. During arm cocking, the American pitchers displayed significantly greater maximum shoulder external rotation and maximum pelvis angular velocity. At the instant of ball release, the American pitchers had significantly greater forward trunk tilt and ball velocity and significantly less knee flexion, which help explain why the American pitchers had 10% greater ball velocity compared to the Korean pitchers. The American pitchers had significantly greater maximum shoulder internal rotation torque and maximum elbow varus torque during arm cocking, significantly greater elbow flexion torque during arm acceleration, and significantly greater shoulder and elbow proximal forces during arm deceleration. While greater shoulder and elbow forces and torques generated in the American pitchers helped generate greater ball velocity for the American group, these greater kinetics may predispose this group to a higher risk of shoulder and elbow injuries.     

Skiing‐Skating

An articulated boot design is commonly used in skiing and skating sports because it allows sagittal plane ankle mobility while still providing critical frontal plane stability. Although articulated boots have been in use for several decades, current manufacturers of these boots differ in their articulation placement. In this study we determined an optimal position of the ankle articulation axis. We also calculated the amount of anterior skin movement that a boot tongue must account for during a full range of ankle motion. Three‐dimensional kinematic data were collected and analyzed from 40 participants moving their right foot through a full range of sagittal plane motion. The calculated horizontal position of the articulation axis was found to be highly predictable from foot length (r = 0.87, standard error of estimate = 3.44 mm), while its vertical component displayed less predictability (r = 0.49, standard error of estimate = 7.46 mm). The expansion required by the boot tongue had a moderate association with foot length and low variability (r = 0.58, standard error of estimate = 0.07 mm). An accurate axis placement will minimize relative motion between the boot cuff and the ankle, reducing friction and motion resistance. An expandable tongue will accommodate full plantar flexion and reduce pressure on the anterior ankle during dorsiflexion, eliminating common pressure‐related injuries.     

Effect of the coefficient of friction of a running surface on sprint time in a sled-towing exercise

This study investigated the effect of the coefficient of friction of a running surface on an athlete's sprint time in a sled-towing exercise. The coefficients of friction of four common sports surfaces (a synthetic athletics track, a natural grass rugby pitch, a 3G football pitch, and an artificial grass hockey pitch) were determined from the force required to tow a weighted sled across the surface. Timing gates were then used to measure the 30-m sprint time for six rugby players when towing a sled of varied weight across the surfaces. There were substantial differences between the coefficients of friction for the four surfaces (μ = 0.21–0.58), and in the sled-towing exercise the athlete's 30-m sprint time increased linearly with increasing sled weight. The hockey pitch (which had the lowest coefficient of friction) produced a substantially lower rate of increase in 30-m sprint time, but there were no significant differences between the other surfaces. The results indicate that although an athlete's sprint time in a sled-towing exercise is affected by the coefficient of friction of the surface, the relationship relationship between the athlete's rate of increase in 30-m sprint time and the coefficient of friction is more complex than expected.     

THE PEDAGOGY OF THE TRANSFORMATION: ECONOMICS EDUCATION IN CENTRAL AND EASTERN EUROPE

This article presents a critical analysis of economics education in central’ and eastern Europe since the 1989 revolutions. The infusión of Western economics teachers and literature, while introducing a new perspective to central and eastern Europe, has also created problems. These problems stem from the narrow perspective and belief in the universal validity of orthodox economic theory held by these teachers and their failure to teach any other perspective. The author advocates a different type of economics education for central and eastern Europe. It includes a broader focus on societal problems and the integration of economic history, comparative economics, economic development, and history of economic thought into economics curricula. Finally, the author recommends that economics education be focussed on giving students a perspective with which to develop their own alternative policies for their respective nations, teaching them that there is more than one economics paradigm and that there are multiple alternative transformation paths.     

Comparing secondary teachers on logical consistency in educational philosophy and flexibility in teaching

This study of secondary inservice teachers was designed to measure the possible relationship between the consistency with which they logically relate philosophical views (theory) to educational ideas (practice) and their teaching flexibility (as demonstrated in actual teaching practice).Using the GNC Scale of Logical Consistency of Ideas about Education, two groups of teachers were identified, i.e., those who were logically consistent in their ideas about education and those who were not so. Each of the logically consistent teachers was found to be so within an empirical, rather than rationalistic framework of educational theory.Flexibility was ascertained by data gathered through the use of the Flanders Verbal Interaction System. Each teacher tape recorded his/her own classes and then completed a Flanders' Matrix.The Mann-Whitney U Test was used as a basis for the statistical analysis. Neither group was found to be either more flexible or to exhibit more indirect behavior within the classroom, i.e., being logically consistent in ideas about education (as measured by the GNC Scale) was not found to be related to being flexible in teaching (as measured by the FVIS).     

Children's perception of gap affordances: bicycling across traffic-filled intersections in an immersive virtual environment

This study examined gap choices and crossing behavior in children and adults using an immersive, interactive bicycling simulator. Ten- and 12-year-olds and adults rode a bicycle mounted on a stationary trainer through a virtual environment consisting of a street with 6 intersections. Participants faced continuous cross traffic traveling at 25 mph or 35 mph and waited for gaps they judged were adequate for crossing. Children and adults chose the same size temporal gaps, but children left far less time to spare between themselves and the approaching vehicle when they crossed the intersection. Relative to adults, children delayed in getting started and took longer to reach the roadway. Discussion focuses on developmental changes in how children coordinate self movement with object movement.