Motivation and Exercise Dependence

The objective of this study was to use self-determination theory to analyze the relationships of several motivational variables with exercise dependence. The study involved 531 exercisers, ranging in age from 16 to 60 years old, who responded to different questionnaires assessing perception of motivational climate, satisfaction of basic psychological needs, motivation types, and exercise dependence. The results of multiple mediation analysis revealed that ego-involving climate and perceived competence positively predicted exercise dependence in a directed and mediated manner through introjected and external regulation. Gender and age did not moderate the analyzed relationships. These results allow us to better understand the motivational process explaining exercise dependence, demonstrating the negative influence of the ego-involving climate in the context of exercise.     

Boycott,Exclusion or Non-participation? Hungary in the Years of the 1920 and 1984 Olympic Games

Sport is a double-edged sword: it has the potential to bring nations together but it can also demonstrate and exacerbate the political tensions and conflicts of the world. Sporting events, especially the Olympic Games, can increase understanding, celebrate commonalities, facilitate cooperation and bridge differences but they can also provide a stage for political rivalries and struggles. This article critically compares the backgrounds of Hungary's non-participation in the 1920 Antwerp and the 1984 Los Angeles Summer Games, given the label ‘boycott’ by the international community.

The unique international political circumstances and Hungary's dependent position restricted the role, strength and efficacy of the contemporary Hungarian sport diplomacy to decide freely. The research implicitly describes the objectives and targets of the actual international alignments, the policy of the Hungarian regime and the processes which resulted in the involuntary non-participation.     

The Changing Role of Sports in Urban Development: A Case Study of Debrecen (Hungary)

In the last few decades, researchers are paying more and more attention to study the connections between sports and urban development. The main purpose of this study is to examine the changing role of sports in urban development through the example of Debrecen and to present the differences between the various historical periods. As a result, it can be concluded that on the one hand, in the inter-war years and in the period after 2000, the broader influence of sports was recognised, and local government made special efforts to use sports for the development of local economy, as well as for the improvement of the image of the city. By contrast, in the period between 1945 and 1990, the main approach used was from the side of mass sports, with satisfying the needs of workers and the general population deemed as the most important. On the other hand, from the early 1930s, i.e. from the beginning of urban planning (with the exception of the period during World War II and the 1950s), the leaders of the city paid special attention to ensure that sports facilities be included in the local development plans of Debrecen.     

Comparison of different theoretical models estimating peak power output and maximal oxygen uptake in trained and elite triathletes and endurance cyclists in the velodrome

Abstract

The primary objective of this study was to examine the relationship between heart rate intensity and pedometer step counts in adolescents. To determine cardiorespiratory fitness, 106 participants (47 boys, 59 girls, mean age 14.2 years, s = 0.8) completed the Queen's College Step Test and were classified as having low, moderate or high cardiorespiratory fitness. Adolescents also completed a 10-min treadmill trial while wearing a pedometer and heart rate monitor. The participants were instructed to maintain their heart rate between 65 and 75% of their maximum heart rate while running or walking on a treadmill. A heart rate of 65–75% maximum was associated with 146 steps per minute (s = 22) in boys and 137 steps per minute (s = 22) in girls. Results of analysis of variance indicated that there was a main effect for level of fitness (F _2,102 = 9.36, P < 0.001). The correlation between mean steps per minute and estimated maximum oxygen consumption was statistically significant (r = 0.44, P < 0.001). The results from this study suggest that a step rate of 130 steps per minute is equal to 65–75% maximum heart rate in low-fit adolescents and achieving 130 steps per minute could be used as an initial goal to improve fitness.     

Effect of target change during the simple attack in fencing

Abstract

The aim of this study was to test the effect that changing targets during a simple long lunge attack in fencing exerts on the temporal parameters of the reaction response, the execution speed, and the precision and the coordination of the movement pattern. Thirty fencers with more than 10 years of experience participated in this study. Two force platforms were used to record the horizontal components of the reaction forces and thereby to determine the beginning of the movement. A three-dimensional (3D) system recorded the spatial positions of the 9 markers situated on the fencer plus the epee, while a moving target was projected on a screen, enabling the control of the target change. The results indicated that when a target change is provoked the reaction time (RT), movement time (MT), and the time used in the acceleration phase of the centre of mass (CM) increases significantly with respect to the attack executed with a straight thrust. The speed and horizontal distance reached by the CM at the end of the acceleration phase (V_X(CM) and S_X(CM), respectively) significantly decreased, while the errors increased. However, the temporal sequence of the movement pattern did not appreciably change.     

The effect of adolescents' sports clubs participation on self-reported mental and physical conditions and future expectations

Abstract

Sports clubs create conditions for people of all ages to pursue a healthy lifestyle through exercise in sports and attend to constructive pedagogical work which creates much value for society. This study investigates the relationship between adolescents' sports clubs participation and self-reported mental and physical conditions and future expectations. The participants were 10,987 pupils in the final three years of their compulsory education in Iceland (aged 14–16 years). The participants completed questionnaires administered to students in the classroom relating to health and behaviour. The results indicate that participation in sports clubs influences adolescents positively; adolescents who work hard at sport not only believe they are in better mental and physical condition, they also believe they can succeed in other areas such as their studies. Sports clubs promote positive influence on adolescents' mental and physical conditions and their future expectations toward work and happiness. It can be concluded that participation in organised sports clubs affects the participants in a positive way.     

Effects of leg dominance on performance of ballet turns (pirouettes) by experienced and novice dancers

Turns (pirouettes) are an important movement in ballet and may be affected by “lateral bias”. This study investigated physiological differences exhibited by experienced and novice dancers, respectively, when performing pirouette with dominant and non-dominant leg supports, respectively. Thirteen novice and 13 experienced dancers performed turns on dominant or non-dominant legs. The maximum ankle plantarflexion, knee extension and hip extension were measured during the single-leg support phase. The inclination angle of rotation axis is the angle between instantaneous rotation axis and global vertical axis in the early single-leg support phase. Both groups exhibited a greater hip extension, knee extension, and ankle plantarflexion when performing a turn on the non-dominant leg. For experienced dancers, the inclination angle of rotation axis during the pre-swing phase was generally smaller for dominant leg support than non-dominant leg. However, no significant difference was found in inclination angle of rotation axis of novice dancers. For experienced dancers, an improved performance is obtained when using the dominant leg for support. By contrast, for novice dancers, the performance is independent of choice of support leg. The significant lateral bias in experienced dancers indicates the possible influence of training. That is, repetitive rehearsal on the preferred leg strengthens the impact of side dominance in experienced dancers.     

Variable training: effects on velocity and accuracy in the tennis serve

Abstract

Variable practice has been shown to be an effective strategy to improve open motor skills. However, the usefulness of this procedure in closed motor skills remains controversial. The following study has the objective of analysing the effects of variability practice in the improvement of a closed skill. The skill studied has been the tennis serve. Thirty young tennis players (13 ± 1.52 years), divided in two groups, took part in this study. One group practiced in variable conditions and the other group in consistency conditions. Both groups performed 12 training sessions (60 serves/session). The variable practice group improved their accuracy significantly compared with the consistency group (F_3.25 = 3.078; P = 0.035). The velocity of serve increased after training in both groups (F_3.25 = 15.890; P = 0.001). The practice in variable conditions seems to be effective in improving the performance of the tennis serve.     

Stabilization and passification of distributed-order fractional linear systems using methods of preservation

This paper studies the stabilization and passification of a class of distributed-order linear time-invariant systems, by using methods of preservation in the frequency domain. Results about preservation of stability and passivity of classical linear time-invariant systems are extended to one more general family of matrix functions. Based on these results, a new approach to the problems of stabilization and passification of distributed-order linear time-invariant systems is presented. Also a result that extends the known techniques for pole placement of classical linear time-invariant systems to the new class of distributed-order linear time-invariant systems is given. Examples are given to show the validity of theoretical results.     

"资源导向"下中小企业集群网络演进的仿真研究

本文从关系嵌入和结构嵌入两个维度界定"资源导向"下的企业网络行为,并应用网络权力分布思想对不同"资源导向"下的企业网络行为进行规则仿真,构建中小企业集群网络演进的多主体仿真模型,对其演进规律和特征进行分析和探讨。本文研究表明,对于中小企业集群而言:(1)群内企业不同的共性行为,会导致不同的集群网络结构;(2)群内企业间的"力量差距"会随着集群的演进逐渐增大,但并非所有的集群都会出现主导企业;(3)集群网络的长期演进轨迹与集群初始状态无关,且群内会形成相对稳定的交流圈;(4)集群网络演进是一个自组织和自无序交替的过程,其系统稳定性主要受企业行为和演化时间的影响。