Boot-insole effects on comfort and plantar loading at the heel and fifth metatarsal during running and turning in soccer

Plantar loading may influence comfort, performance and injury risk in soccer boots. This study investigated the effect of cleat configuration and insole cushioning levels on perception of comfort and in-shoe plantar pressures at the heel and fifth metatarsal head region. Nine soccer academy players (age 15.7 ± 1.6 years; height 1.80 ± 0.40 m; body mass 71.9 ± 6.1 kg) took part in the study. Two boot models (8 and 6 cleats) and two insoles (Poron and Poron/gel) provided four footwear combinations assessed using pressure insoles during running and 180° turning. Mechanical and comfort perception tests differentiated boot and insole conditions. During biomechanical testing, the Poron insole generally provided lower peak pressures than the Poron/gel insole, particularly during the braking step of the turn. The boot model did not independently influence peak pressures at the fifth metatarsal, and had minimal influence on heel loads. Specific boot-insole combinations performed differently (P < 0.05). The 8-cleat boot and the Poron insole performed best biomechanically and perceptually, but the combined condition did not. Inclusion of kinematic data and improved control of the turning technique are recommended to strengthen future research. The mechanical, perception and biomechanical results highlight the need for a multi-faceted approach in the assessment of footwear.     

Can subjective comfort be used as a measure of plantar pressure in football boots?

Comfort has been shown to be the most desired football boot feature by players. Previous studies have shown discomfort to be related to increased plantar pressures for running shoes which, in some foot regions, has been suggested to be a causative factor in overuse injuries. This study examined the correlation between subjective comfort data and objective plantar pressure for football boots during football-specific drills. Eight male university football players were tested. Plantar pressure data were collected during four football-specific movements for each of three different football boots. The global and local peak pressures based on a nine-sectioned foot map were compared to subjective comfort measures recorded using a visual analogue scale for global discomfort and a discomfort foot map for local discomfort. A weak (r_s = ?0.126) yet significant (P < 0.05) correlation was shown between the peak plantar pressure experienced and the visual analogue scale rated comfort. The model only significantly predicted (P > 0.001) the outcome for two (medial and lateral forefoot) of the nine foot regions. Subjective comfort data is therefore not a reliable measure of increased plantar pressures for any foot region. The use of plantar pressure measures is therefore needed to optimise injury prevention when designing studded footwear.     

The effect of boot stiffness on field and laboratory flexural behavior of alpine ski boots

The aim of this work was to study the effect of boot stiffness on the field and laboratory flexural behavior of alpine ski boots. Ski boots have a direct influence on performance, safety, and comfort of alpine skiers. Despite their technological evolution during a number of years, the parameters used in the evaluation of boot stiffness are not yet standardized and still require a shared engineering approach to achieve common quantitative definitions to be used either in boot classification or in boot selection for the different users. This work reports the boot flexion angles between shell and cuff and between cuff and tibia, collected during slalom tests on three boots with different nominal Flex Index. The laboratory data collected on the same boots under conventional cyclic bending tests are reported and compared with the field data for the development of a new test method more representative of the field behavior. As a result, clear definitions of Flex Index and of boot stiffness are introduced: boot stiffness had a clear effect on both the field and the laboratory flexural behavior of boots.     

全国冬运会“北冰南展西扩”战略的价值阐释

运用文献资料法、数理统计法等,在分析我国历届冬运会开展的现状以及发展规律的基础上,从经济价值、文化价值、社会价值的视角阐述全国冬运会“北冰南展西扩”战略的价值。研究认为：全国冬运会举办城市逐步走出东北,南展西扩战略时机业已成熟;“北冰南展西扩”战略可拉动当地冰雪产业发展,完善以冰雪运动为主的经济产业链,从而带来可观的经济效益;冰雪文化与区域文化相融合,能体现出文化的魅力。调整冬季运动项目结构,将会进一步促进冬季运动会经济价值、社会价值的实现。     

Power and pacing calculations based on real-time locating data from a cross-country skiing sprint race

Pacing strategies in cross-country skiing have been investigated in several studies. However, none of the previous studies have been verified by collected skiing data giving the skiing velocities along a measured track. These can be used to calculate the propulsive power output. Collected real-time positioning data from a cross-country sprint skiing race were used to estimate the propulsive power by applying a power balance model. Analyses were made for the time-trial and the final for one female and one male skier. The average propulsive power over the whole race times were 311 and 296 W during the time trial and 400 and 386 W during the final, for the female and male skier, respectively. Compared to the average propulsive power over the whole race, the average active propulsive phases were calculated as 33 and 44% higher in the time trials and 36 and 37% higher in the finals for the female and male, respectively. The current study presents a novel approach to use real-time positioning data to estimate continuous propulsive power during cross-country sprint skiing, enabling in-depth analyses of power output and pacing strategies.     

Optimal ankle axis position for articulated boots

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.     

Time and money expenditure in sports participation: The role of income in consuming the most practiced sports activities in Flanders

Given the recent economic crisis and the risen poverty rates, sports managers need to get insight in the effect of income and other socio-economic determinants on the household time and money that is spent on sports participation. By means of a Tobit regression, this study analyses the magnitude of the income effect for the thirteen most practiced sports by households in Flanders (the Dutch speaking part of Belgium), which are soccer, swimming, dance, cycling, running, fitness, tennis, horse riding, winter sports, martial arts, volleyball, walking and basketball. The results demonstrate that income has a positive effect on both time and money expenditure on sports participation, although differences are found between the 13 sports activities. For example, the effect of income on time and money expenditure is relatively high for sports activities like running and winter sports, while it is lower for other sports such as fitness, horse riding, walking and swimming. Commercial enterprises can use the results of this study to identify which sports to focus on, and how they will organise their segmentation process. For government, the results demonstrate which barriers prevent people from taking part in specific sports activities, based upon which they should evaluate their policy decisions.     

Pose tracking with rate gyroscopes in alpine skiing

The motion capture of alpine skiing is technically challenging. Motion capture systems using inertial sensors such as gyroscopes and accelerometers have begun to be used in sport. The capture volume of the system can be large enough to cover the whole area of a particular sporting event, because sensors are affixed to the human body itself. The current study developed a method of tracking the pose of an alpine skier using gyroscopes for 3 min with a tracking error of 2° (RMSE). The technical significance of the presented method, which uses one common simple algorithm to improve measurement of pose, applies to many experimental conditions. The adoption of a high resolution (24 bit) analog-to-digital converter and high sampling rate (1 kHz) also contribute to the improvement of measurement time.     

Coaches’ implicit associations between size and giftedness: implications for the relative age effect

The relative age effect (RAE) is a well-established phenomenon in education and sports. Coaches have been assumed to be important social agents of RAE via biased selection decisions in favour of children with maturation advantages. In the present research, we used the Implicit Association Test to investigate automatic associations between body size and a player’s domain-specific giftedness amongst youth baseball (N = 18) and youth soccer coaches (N = 34). We found medium to strong automatic associations between body size and player giftedness (baseball: M_D = 0.62; soccer: M_D = 0.51). Specifically, taller players were associated with positive performance-related attributes, whereas smaller players were associated with negative attributes. The results are in line with theories of grounded cognition by showing that the abstract concept of “sport giftedness” is partly grounded in the perception of physical height amongst youth sports coaches. We argue that this grounded cognition has the potential to influence coaches’ selection decisions and in turn account for RAE as coaches are biased towards physically more matured players, even when no apparent performance advantage is evident.     

美学视阈下冬季体育教学的审美教育

冬季体育的教学目标不仅是增强学生的体质,还应在教学中培养学生的审美意识和审美能力。在美学视阈下深层次挖掘冬季体育运动中蕴藏的美学元素,总结出目前冬季体育教学存在缺乏对冬季体育运动美的发现,冬季体育教学过程缺少美的运用,冬季体育教学环境欠缺美的体现等现状;提出树立美育观,充分挖掘冬季体育教学中美的元素,将美育贯穿于冬季体育教学的全过程,提高教师美学素养,营造冬季体育教学美育环境等冬季体育教学审美教育的实施途径,为更好地完成冬季体育教育教学目标提供理论参考。     

Understanding users’ continuance intentions to use smart-connected sports products

The authors investigate the salient factors that influence users’ continuance intentions to use smart-connected sports products. Drawing on the theory of planned behavior (TPB), they propose that three major factors—attitude, social comparison as social influence, and perceived behavioral control—significantly influence users’ continuance intentions. Smart-connected sports product users (N = 236) participated in this study. Collected data were analyzed using Partial Least Squares (PLS) modeling. Results suggest two different attitudinal beliefs—technology-related (perceived usefulness) and fashion-related (perceived comfort) factors—of smart-connected sports products influence attitudes toward the products and that control-related factors (technical functionality and facilitating conditions) play a role in regulating users’ volitional behaviors from their intentions. The authors highlight user beliefs of smart-connected sports products based on TPB and propose a concrete, practical set of factors that practitioners might manipulate to facilitate users’ continuance intentions to use smart-connected sports products.     

Musculoskeletal injuries in physical education versus non-physical education teachers: a prospective study

Physical education (PE) teachers have a physically demanding job, putting them at a considerable risk for musculoskeletal injuries. To structurally develop tailored injury prevention programmes for PE teachers, a clear understanding of the extent, characteristics and underlying factors of their musculoskeletal injuries compared to referents is necessary. Therefore, the current study prospectively followed 103 PE teachers and 58 non-PE teachers, who registered musculoskeletal injuries and time of exposure to sports participation during one school year. Pearson χ²-tests and independent samples t-tests determined significant differences between PE and non-PE teachers regarding demographics and variables possibly related to injury occurrence. PE teachers had 1.23 and non-PE teachers 0.78 injuries/teacher/school year. This difference was significantly different after adjustment for hours spent weekly on intracurricular teaching during the career and for injury history during the preceding six months (P = 0.009; OR = 0.511; 95% CI = 0.308–0.846). PE teachers’ most affected body parts were the knee and the back. PE teachers had a more extensive injury history (P < 0.001), a higher work- (P < 0.001) and sport index (P < 0.001), practiced more sports (P < 0.002) and taught more extracurricular sports (P = 0.001). Future injury prevention programmes should take account for the great injury history and heavy physical load in PE teachers.     

基于内容分析法的我国冰雪运动政策研究

推广冰雪运动是体育强国建设的重要举措之一,是新时代促进体育事业发展的组成内容。运用内容分析法,从政策工具与冰雪运动价值判断两个维度对《群众冬季运动推广普及计划(2016-2020年)》和《冰雪运动发展规划(2016-2025年)》的政策文本进行分析,探讨体育强国建设中的冰雪运动政策制定规律及问题。研究发现:我国冰雪运动政策存在需求型政策工具过少、供给型政策工具不足和环境型政策工具较多的结构失衡问题;冰雪运动价值判断维度总体呈现"一中心三围绕两辅助"的发展布局;大众体育与体育产业领域侧重环境型建设,欠缺供给型和需求型的助推;学校体育领域偏重供给型建设,环境型和供给型搭配适中;体育文化和竞技体育领域关注面缺乏。最后针对政策存在的问题提出建议:合理搭配冰雪运动政策工具的使用;注重冰雪运动政策的侧重点;阶段性调整和优化政策工具;加强实施的监管和调控。     

高校冬季体育教学的创新

我国高校冬季体育教学的转变、改革与创新的进程,在教育全面由原来的知识教育向行为教育转变的背景中略显迟缓,导致我国大学生体质与健康继续呈现缓慢下降、肥胖检出率继续增加的现象,加强高校冬季体育教学的创新已经成为当前一个重要的课题。认为高校冬季体育教学缺乏人性化的方法、手段,增强学生体质无法落实到实处;教学理念落后,教学内容单一,缺乏时代气息等是高校冬季体育教学中存在的主要问题。提出明确冬季体育教学目标,发挥学生的主体作用;以大学生的需求为导向创新教学内容;从尊重每位学生个体的角度出发,采取灵活、实效的教学方法等途径实现我国高校冬季体育教学的改革与创新。     

Identification of temporal factors related to shot performance for indoor recurve archery

The purpose of this study was to investigate the temporal phases of the archery shot cycle that distinguish the arrows distance from centre, in an attempt to understand critical factors that affect performance. Fifteen archers of varying ability each performed 30 shots at 18 m. Fourteen potential predictor variables were measured for statistical modelling by stepwise multiple linear regression. The results show that pre-shot time (pre-performance routine), follow-through time (post-performance routine), aiming time, speed of the arrow and the %variation in clicker-release time, account for 7.7% of the variation in predicting shot performance. The results have implications for practice demonstrating factors that coaches should focus on to develop their athletes. Further work on pre-, but more importantly, post-performance routines are needed generally within sport research as they are lacking and have been shown to be important contributing factors in a number of sports.     

我国申办冬奥会志愿服务的前瞻性思考

通过对我国申办冬奥会、冬奥会志愿服务和冬季体育志愿服务之间的关系进行深入分析,阐述了申办冬奥会志愿服务具有的社会价值、文化价值、教育价值和经济价值,对在申办冬奥会过程中完善冬季体育志愿服务体系,做出培育冬季体育志愿者的社会资本,形成冬季体育志愿服务的持久化、常态化,建设专业化、制度化的冬季体育志愿服务队伍等一系列前瞻性思考,以期推动冬季体育运动在我国有一个新的更大的发展,成功申办和举办冬奥会.     

我国单板U型场地滑雪运动员失误动作种类、特征及其原因分析——中国·哈尔滨国际雪联亚洲杯单板U型场地滑雪比赛综述

采用文献资料、现场观察和录像分析等方法,对中国运动员在亚洲杯单板U型场地滑雪比赛中出现的失误动作进行统计分析后发现：运动员主要存在着场地利用不足、空中动作没完成和落地摔倒等失误现象。而这些失误的存在主要与运动员大赛经验较少、技术水平不高、伤病及心理压力过大等因素有关。为此提出完善技术水平、预防运动员伤病和对运动员进行心理辅导等建议,为我国单板U型场地滑雪运动的进一步发展提供参考。     

A simple mechanical model for simulating cross-country skiing,skating technique

The role of simulation models in sport disciplines has become relevant lately due to the multiple advantages that they may offer sports teams, coaches and practitioners. This paper develops and presents a simple three-dimensional multibody dynamic model of a cross-country skier, modeling a single propulsion phase to obtain the kinetic parameters involved in the movement. A professional Olympic-level skier performed the skating technique without poles in a ski tunnel under controlled conditions and on an incline plane. Then, with a force acquisition system attached to the ski bindings and a motion capture system set on site, the leg resultant forces and the movement of specific points of the skier’s lower body were acquired. The data obtained from the motion capture system were used as the prescribed kinematic input data in the multibody model and the measured force was used later as a parameter of comparison with the results of the simple model. After simulating the technique, the calculated resultant forces seem to be in agreement with those measured in the field.     

2015年日本滑雪场滑雪者受伤情况调查分析

随着滑雪成为冬季人们喜爱的运动项目之一,近年来参与这项运动的人数增多,损伤人数也呈上升趋势,滑雪者受伤或者出现安全事故的几率也增大,制约着滑雪产业的发展。运用文献资料法、调查访问法、问卷调查法、逻辑分析法和数理统计法等研究方法对2015年日本18家滑雪场滑雪者受伤情况进行调查,分析滑雪者受伤原因并且提出滑雪者应该养成良好的滑雪习惯,佩戴安全的滑雪头盔、护腕、护肘,身着色泽鲜艳、保暖、防水的滑雪着装,掌握正确的滑行技术动作和正确安全的摔倒方法,提高安全意识和自我防护意识,滑雪场提高其工作能力和素质,完善各项救护设施,以确保有事故发生时能使受伤者得到及时有效的救治等预防措施及建议,旨在提高和加强滑雪爱好者的自我防护意识,减少滑雪事故的发生。     

The impact of start strategy on start performance in alpine skiing exists on flat,but not on steep inclines

Here, we explored the relationship between incline and start strategy during alpine skiing. Eight FIS skiers performed starts on a flat (3°) and steep (21°) incline employing five different strategies. Their times, trajectories and velocities were monitored with a GNSS system and video. A significant interaction was observed between slope incline and start strategy with respect to the skier’s exit velocity (p < 0.001, ?²_p = 0.716), but not for the start section time (p = 0.732, ?²_p = 0.037). On the almost flat incline, both section time (p = 0.022, ?²_p = 0.438) and exit velocity (p < 0.001, ?²_p = 0.786) were influenced significantly by start strategy, with four V2 skate-pushes being optimal. On the steep incline, neither section time nor exit velocity was affected significantly by start strategy, the fastest section time and exit velocity being attained with four and two V2 skate-pushes, respectively. In conclusion, these findings demonstrate that the start strategy exerts considerable impact on start performance on almost flat inclines, with strategies involving three or more V2 skate-pushes being optimal. In contrast, start performance on the steep incline was not influenced by strategy.