Unstable footwear as a speed-dependent noise-based training gear to exercise inverted pendulum motion during walking

ABSTRACT

Previous research on unstable footwear has suggested that it may induce mechanical noise during walking. The purpose of this study was to explore whether unstable footwear could be considered as a noise-based training gear to exercise body center of mass (CoM) motion during walking. Ground reaction forces were collected among 24 healthy young women walking at speeds between 3 and 6 km h^?1 with control running shoes and unstable rocker-bottom shoes. The external mechanical work, the recovery of mechanical energy of the CoM during and within the step cycles, and the phase shift between potential and kinetic energy curves of the CoM were computed. Our findings support the idea that unstable rocker-bottom footwear could serve as a speed-dependent noise-based training gear to exercise CoM motion during walking. At slow speed, it acts as a stochastic resonance or facilitator that reduces external mechanical work; whereas at brisk speed it acts as a constraint that increases external mechanical work and could mimic a downhill slope.     

A Theoretical Analysis of How Segmentation of Dynamic Visualizations Optimizes Students' Learning

This article reviews studies investigating segmentation of dynamic visualizations (i.e., showing dynamic visualizations in pieces with pauses in between) and discusses two not mutually exclusive processes that might underlie the effectiveness of segmentation. First, cognitive activities needed for dealing with the transience of dynamic visualizations impose extraneous cognitive load, which may hinder learning. Segmentation may reduce the negative effect of this load by dividing animations into smaller units of information and providing pauses between segments that give students time for the necessary cognitive activities after each of those units of information. Second, event segmentation theory states that people mentally segment dynamic visualizations during perception (i.e., divide the information shown in pieces). Segmentation of dynamic visualisation could cue relevant segments to students, which may aid them in perceiving the structure underlying the process or procedure shown.     

Group-Based Emotions: Evidence for Emotion-Performance Relationships in Team Sports

Purpose: In team sports, players have to manage personal interests and group goals, emphasizing intricacies between personal and social identities. The focus of this article was to examine the effect of identity mechanisms on appraisal processes, based on the following research question: Does the level of self-abstraction (low [personal identity] versus high [social identity]) lead to group-based emotions and influence performances? Method: An experimental design was used in which the level of self-abstraction was manipulated through the induction of a self- versus a team-oriented goal. Thirty elite male rugby players (M_age = 19.06, SD = 0.78, randomly split) participated in a match reproducing conditions similar to those of official games. Individual and perceived team-level emotions and performance were measured 17 times during the match. Results: Linear Mixed Effects models showed that a high level of self-abstraction: (a) led to more positive and less negative individual (variances explained: 52% and 46%) and perceived team-referent (variances explained: 57% and 40%) emotions; (b) reduced the correlation of team-referent emotions with individual ones; and (c) positively influenced team and individual performances (variances explained: 50% and 19%). Moreover, after controlling for potential effects of the level of self-abstraction, only positive team-referent emotions influenced performance. Conclusions: This study is the first to experimentally manipulate athletes’ social identity to examine group-based emotions in sport. Challenging the usual intrapersonal approaches, these findings suggested that social identity and its association with team-referent emotions could be one of the key dimensions of emotion-performance relationships in team sports.     

Rotation sequence to report humerothoracic kinematics during 3D motion involving large horizontal component: application to the tennis forehand drive

The aim of this study was to examine the respective aptitudes of three rotation sequences (Y_tX_f′Y_h′′, Z_tX_f′Y_h′′, and X_tZ_f′Y_h′′) to effectively describe the orientation of the humerus relative to the thorax during a movement involving a large horizontal abduction/adduction component: the tennis forehand drive. An optoelectronic system was used to record the movements of eight elite male players, each performing ten forehand drives. The occurrences of gimbal lock, phase angle discontinuity and incoherency in the time course of the three angles defining humerothoracic rotation were examined for each rotation sequence. Our results demonstrated that no single sequence effectively describes humerothoracic motion without discontinuities throughout the forehand motion. The humerothoracic joint angles can nevertheless be described without singularities when considering the backswing/forward-swing and the follow-through phases separately. Our findings stress that the sequence choice may have implications for the report and interpretation of 3D joint kinematics during large shoulder range of motion. Consequently, the use of Euler/Cardan angles to represent 3D orientation of the humerothoracic joint in sport tasks requires the evaluation of the rotation sequence regarding singularity occurrence before analysing the kinematic data, especially when the task involves a large shoulder range of motion in the horizontal plane.     

Direct regional economic impact of Germany’s 1. FC Kaiserslautern through participation in the 1. Bundesliga

In discussions about the use of public money for popular sports such as clubs in Germany’s 1. Bundesliga, it is often argued that the funds are well invested due to the cash flows generated by these organizations for their home regions. However, others claim the opposite. They argue that actually no positive impact is generated and, even worse, that money is leaving the region due to the clubs. The study presented here analyses the financial flows generated by the 1. FC Kaiserslautern for its home city (Kaiserslautern) and home state (Rhineland-Palatinate) during the 2010/11 season when the club participated in the 1. Bundesliga. Based on a 3-step model, the economic impact is calculated by considering spectator spending and cash flows generated by the business activities of the club. It turns out that additional cash flows of approximately €16.5 million and €25.8 million were generated for the state and the city, respectively.     

When is a discovery? The affective dimensions of discovery in music consumption

ABSTRACT

This article explores the concept of music discovery and seeks to provide a definition of the act of discovering music content. Research on music consumption has weakly theorized what the moment of “discovery” consists of, since it has been more preoccupied with debates about the conditions of discoveries, which either highlight the importance of individuals’ social milieus or the enhanced technological agency that they enjoy in the digital age. Drawing on qualitative data about musical experiences, this article frames discoveries as affective responses to music content that occur within individuals’ life narratives and mediate their interpretation and definition of music.     

Measurement of contact forces on a kayak ergometer with a sliding footrest–seat complex

Kinematic analysis is done by measurement of the position of bodies, followed by differentiation to get the accelerations of the centres of mass, and it is widely used in sport research. Another common approach is to measure the forces directly. Our intention here is to perform both a kinematic and a kinetic analysis of the same athlete-equipment system, in this case an athlete on a sliding kayak ergometer, with the aim of exploring the errors that may occur with each measurement type. The kayak ergometer with a sliding trolley, instrumented by seven uniaxial force sensors and two goniometers, was placed in a filming area. The instrumentation was validated in the direction of the anteroposterior axis using Newton’s second law. Ten athletes paddled at 92 strokes per minute, following a stationary phase. The comparison between the net force and the time-derivative of the linear momentum indicated a friction level of about 20 N between the trolley and the frame. Other errors came mainly from the inertial parameters of the trunk. A first analysis of contact forces shows a large inter-subject variability, in particular for the forces applied to the footrest and the seat.     

A positive psychological viewpoint for success at school – 10 characteristic strengths of the Finnish high-achieving students

People who exploit their strengths flourish; they are not only engaged with their goals, but also to their well-being and the content of life. In this study, interest focused on the high-achieving students in the Finnish general upper secondary education, in other words, on straight-A graduates’ characteristic strengths. This was a narrative study in which the data were obtained through written narratives and narrative interviews among 14 Finnish straight-A graduates. The data were analyzed with narrative analyzing methods. Ten typical strengths found and further categorized into three key dimensions were: (1) the thirst of knowledge and passion for learning, (2) fortitude and authenticity, and (3) love. This study implied that the youth’s school paths and well-being actively increased their own characteristic strengths.