Validity of a device designed to measure braking power in bicycle disc brakes

Real-world cycling performance depends not only on exercise capacities, but also on efficiently traversing the bicycle through the terrain. The aim of this study was to determine if it was possible to quantify the braking done by a cyclist in the field. One cyclist performed 408 braking trials (348 on a flat road; 60 on a flat dirt path) over 5 days on a bicycle fitted with brake torque and angular velocity sensors to measure brake power. Based on Newtonian physics, the sum of brake work, aerodynamic drag and rolling resistance was compared with the change in kinetic energy in each braking event. Strong linear relationships between the total energy removed from the bicycle-rider system through braking and the change in kinetic energy were observed on the tar-sealed road (r² = 0.989; p < 0.0001) and the dirt path (r² = 0.952; p < 0.0001). T-tests revealed no difference between the total energy removed and the change in kinetic energy on the road (p = 0.715) or dirt (p = 0.128). This study highlights that brake torque and angular velocity sensors are valid for calculating brake power on the disc brakes of a bicycle in field conditions. Such a device may be useful for investigating cyclists’ ability to traverse through various terrains.     

大学课程设计自学指南:如何设计课程以促进意义深远的学习

作为大学老师,为了达到好的教学效果,我们必须能够做好两项活动,既要做好课程设计,又要做好师生互动.就这两项活动而言,我们的课程设计能力常常是制约因素.《创造意义深远的学习经历:大学课程整合设计方案》一书作者,美国奥克拉荷马大学教学发展项目部主任迪·芬克博士撰写了一份大学课程设计的自学指南,旨在给大家介绍一套系统有效的课程设计程式,帮助大家学会怎样进行课程设计.指南包括课程整合设计的三个主要阶段,每阶段包括开篇的介绍性评价,读者可以加以使用的工作簿,以及读者在课程设计过程中可以对自己提出的一些问题,以对自己的设计实践进行推敲.     

Physical Exercise During the Morning School‐Break Improves Basic Cognitive Functions

Physical activity has not only been associated with increased physical and mental health, but also with beneficial effects on various cognitive and brain functions. This study investigated the effects of a motor and coordination oriented exercise intervention on academic achievements, attention/concentration ability, and on different facets of creative potential in a sample of school‐aged children between 11 and 14 years. The intervention was conducted during the morning school‐break over a time period of 4 weeks (5 units per week). The intervention was associated with beneficial effects on attention/concentration ability, basic arithmetic competence, and the fluency facet of creative potential. The finding that regular physical exercise during the morning break improves some basic academic and cognitive functions may motivate efforts to implement physical activity programs as promising and effective tools in the everyday school‐routine of the children to stimulate basic neurocognitive functions.     

Quantification of brake data acquired with a brake power meter during simulated cross-country mountain bike racing

There is currently a dearth of information describing cycling performance outside of propulsive and physiological variables. The aim of the present study was to utilise a brake power meter to quantify braking during a multi-lap cross-country mountain bike time trial and to determine how braking affects performance. A significant negative association was determined between lap time and brake power (800.8 ± 216.4 W, mean ± SD; r = ?0.446; p < 0.05), while the time spent braking (28.0 ± 6.4 s) was positively associated with lap time (314.3 ± 37.9 s; r = 0.477; p < 0.05). Despite propulsive power decreasing after the first lap (p < 0.05), lap time remained unchanged (p > 0.05) which was attributed to decreased brake work (p < 0.05) and brake time (p < 0.05) in both the front and rear brakes by the final lap. A multiple regression model incorporating braking and propulsion was able to explain more of the variance in lap time (r² = 0.935) than propulsion alone (r² = 0.826). The present study highlights that riders’ braking contributes to mountain bike performance. As riders repeat a cross-country mountain bike track, they are able to change braking, which in turn can counterbalance a reduction in power output. Further research is required to understand braking better.     

Training load characteristics and injury and illness risk identification in elite youth ski racing: A prospective study

PurposeThe study aimed to investigate the role of training load characteristics and injury and illness risk in youth ski racing.MethodsThe training load characteristics as well as traumatic injuries, overuse injuries, and illnesses of 91 elite youth ski racers (age = 12.1 ± 1.3 years, mean ± SD) were prospectively recorded over a period of 1 season by using a sport-specific online database. Multiple linear regression analyses were performed to monitor the influence of training load on injuries and illnesses. Differences in mean training load characteristics between preseason, in-season, and post-season were calculated using multivariate analyses of variance.ResultsDifferences were discovered in the number of weekly training sessions (p = 0.005) between pre-season (4.97 ± 1.57) and post-season (3.24 ± 0.71), in the mean training volume (p = 0.022) between in-season (865.8 ± 197.8 min) and post-season (497.0 ± 225.5 min) and in the mean weekly training intensity (Index) (p = 0.012) between in-season (11.7 ± 1.8) and post-season (8.9 ± 1.7). A total of 185 medical problems were reported (41 traumatic injuries, 12 overuse injuries, and 132 illnesses). The weekly training volume and training intensity was not a significant risk factor for injuries (p > 0.05). Training intensity was found to be a significant risk factor for illnesses in the same week (β = 0.348; p = 0.044; R² = 0.121) and training volume represents a risk factor for illnesses in the following week (β = 0.397; p = 0.027; R² = 0.157).ConclusionA higher training intensity and volume were associated with increased illnesses, but not with a higher risk of injury. Monitoring training and ensuring appropriate progression of training load between weeks may decrease incidents of illness in-season.     

Female athlete endorsers: Determinants of effectiveness

In drawing from social role theory and the match-up hypothesis, the purpose of this study was to determine influential variables regarding the effectiveness of female athlete endorsers. A 2 (gender appropriate/gender inappropriate) × 2 (sport related product/non-sport related product) experiment was conducted with 296 participants from four different universities throughout the United States. Results indicated that type of sport had little effect on credibility measures. Further, the athlete's sport had no effect on athlete-product fit. The most important aspect relative to purchase intentions was the product being endorsed, not the sport in which the athlete competed. Results are discussed in terms of practical implications and theoretical considerations.     

Supporting policy-making with social media and e-participation platforms data: A policy analytics framework

E-participation enables citizens to have an impact on policy-making through electronic means. Two of the most popular channels are social media and dedicated e-participation platforms. However, the ideas, comments, discussions of citizens on these two channels generate a lot of data to be processed by political representatives or public agents afterwards. Despite the existence of various techniques for social media analytics, literature is scarce regarding the analysis techniques to mine e-participation platforms as well as the possible combination of insights between the two channels.In order to address these gaps, we design a policy analytics framework to leverage insights from e-participation platforms and social media through relevant data analytics to support policy-making. In order to do so, we rely on the Design Science Research methodology. Through the analysis of four different cities in Belgium (Liège, Mons, Marche-en-Famenne, Leuven), we identify policy-makers' requirements and needs of information from platforms and social media. Then, we explore data analysis techniques to address those requirements. Finally, we design an actionable framework, present it as an interactive dashboard and iteratively test it on the case of Liège. This policy analytics framework supports each step of the traditional policy-making process with appropriate data analytics applied to the two sources.