Intra-task variability of trunk coordination during a rate-controlled bipedal dance jump

In this study, we investigated trunk coordination during rate-controlled bipedal vertical dance jumps. The aims of the study were to investigate the pattern of coordination and the magnitude of coordination variability within jump phases and relative to phase-defining events during the jump. Lumbar and thoracic kinematics were collected from seven dancers during a series of jumps at 95 beats per minute. The vector coding technique was used to quantify the pattern and variability of trunk coordination. Coordination was predominantly anti-phase during propulsion and landing. Mean coordination variability peaked just before the landing phase and at the transition from landing to propulsion phases, and was lowest during the propulsion phase just before toe-off. The results indicate that peaks in variability could be explained by task and phase-specific biomechanical demands.     

Dancers with patellar tendinopathy exhibit higher vertical and braking ground reaction forces during landing

Dancers are exposed to the effects of repetitive jumping and leaping as are other athletes that tend to develop patellar tendinopathy. Greater vertical ground reaction forces occur during landing from a dance leap than during takeoff and during other common athletic activities. The purposes of this study were: (1) to compare the landing ground reaction force profiles of participants with and without clinically diagnosed patellar tendinopathy, and (2) to determine the strength of the relationship between landing angle, and braking impulse. Eighteen elite pre-professional dancers (12 healthy, 6 with patellar tendinopathy; both groups 50% male) performed sauts de chat for kinetic and kinematic analysis. Dancers with patellar tendinopathy demonstrated greater peak vertical ground reaction force and impulse (36% and 15% greater, respectively). Dancers with patellar tendinopathy demonstrated greater peak braking ground reaction force and impulse (82% and 126% greater, respectively). Landing angle explained 67% of the braking impulse. Dancers with patellar tendinopathy exhibited greater vertical and braking impulses than healthy dancers. Braking impulse was strongly correlated with landing angle. While there was no difference between groups in landing angle, dancers with patellar tendinopathy exhibited greater braking impulse than their non-tendinopathic counterparts, even at similar landing angles.     

Developmental changes in auditory temporal perception

Infants, preschoolers, and adults were tested to determine the shortest time interval at which they would respond to the precedence effect--an auditory phenomenon produced by presenting the same sound through 2 loudspeakers with the input to 1 loudspeaker delayed relative to the other. The delayed sound is not localized at its source until time delays between onsets are lengthened beyond a critical limit, or threshold. Thresholds for the precedence effect were defined as the delay interval below which listeners respond only to the leading loudspeaker and above which they respond to both loudspeakers. Threshold estimates were determined for adults and preschoolers with an ascending and descending series, followed by a method of constant stimuli series. Infants were trained to respond to the delayed sound using a visually reinforced headturning procedure. For clicks, preschoolers' and adults' thresholds were around 12 msec, while 6-month-olds stopped responding to the delayed sound around 25 msec. A similar developmental difference in threshold was expressed between preschoolers and adults for a more complex sound, with younger subjects hearing the precedence effect over a longer time delay.     

Kinematic and kinetic analyses of the toes in dance movements

Due to the significant amount of time dancers spend on the forefoot, loads on the metatarsophalangeal joints are likely high, yet vary between dance movements. The purpose of this study was to compare joint motion and net joint moments at the metatarsophalangeal joints during three different dance movements ranging in demands at the foot and ankle joints. Ten healthy, female dancers (27.6 ± 3.2 years; 56.3 ± 6.9 kg; 1.6 ± 0.1 m) with an average 21.7 ± 4.9 years of dance training performed relevés (rising up onto the toes), sautés (vertical bipedal jumps), and saut de chat leaps (split jumps involving both vertical and horizontal components). Metatarsophalangeal joint kinematics and kinetics in the sagittal plane were calculated. Total excursion and peak net joint moments during rising or push-off were compared between the three dance movements. Greater extension of the metatarsophalangeal joints was seen during relevés compared to sautés or saut de chat leaps, and the largest metatarsophalangeal net joint moments were seen during saut de chat leaps. The metatarsophalangeal joints frequently and repetitively manage external loads and substantial metatarsophalangeal extension during these three dance movements, which may contribute to the high rate of foot and ankle injuries in dancers.     

Selected aspects of conditions in the use of new media as an important part of the training of teachers in the Czech Republic and Poland - differences,risks and threats

The paper presents the complex problems of preparation of pedagogy students to work as teachers in the context of their readiness to use ICT in the didactic process. The complexity of this subject matter has been proved by the current, ongoing, discussion about the direction of the expected transformations of contemporary schools and the prospective teachers education system in the age of prevalent digitization. Considering the complexity of conditions, the main research problem has been formulated as follows: Conditions of what type affect the preparation of prospective teachers to use new media in learning and teaching process?. Thus, the empirical analysis conducted in the paper focuses on the following issues: the style of using new media by students, identification of students’ attitudes towards media, subjective (from the students’ point of view) assessment of how university level schools are prepared to shape modern media competences among their students and self-evaluation of media and IT competences in the group of prospective teachers. Czech and Polish students, despite being the so called digital natives, do not present homogeneous styles of using new media. They also reveal different attitudes toward applying digital solutions to the didactic process. Factors such as: low evaluation of one’s own competences or lack of evaluation in this area, lack of creative approach to the use of new media, lack of education in the area of new applications, lack of skills necessary to handle basic digital tools (e.g. interactive board, e-learning platforms) negatively affect, in most cases, the attitude toward the active use of ICT tools in future didactic work. On the basis of the gathered empirical data and inductive qualitative analysis a typology of students attitudes toward new media was developed. It consists of four categories: techno-optimist, techno-realist, techno-pessimist and techno-ignorant. The whole of analyses has the character of comparative research and involves two neighboring countries of the Visegrad Group: Poland (N?=?466) and Czech Republic (N?=?168).     

Relevance matters. Eighteen-month-olds’ use of relevant informative pointing as a predictor of two-year-olds’ language abilities / La relevancia es importante. El uso de gestos deícticos relevantes e informativos por parte de niños de año y medio como factor predictor de las capacidades lingüísticas a los dos años

Abstract

The significance of pointing gestures in the development of linguistic communication is linked to their referential character and formation of common ground in use of gestures and speech. Our longitudinal study aimed to define the nature of this relationship more precisely and to explore whether the relevance vs lack of relevance of a child’s pointing gestures is related to development of language abilities. We developed a special protocol to measure relevant and irrelevant pointing gestures in 18-month-olds, sampled production of spontaneous speech and measured their language comprehension at two years of age. A group of 343 children was tested, and using structural equation modelling we showed that relevant gestures predict the level of development of language production and comprehension. As predicted, this association was not applied to irrelevant gestures. It is likely that a child’s more frequent use of relevant pointing gestures helps the caregiver to recognize the child’s communicative intentions and to comment on his/her behaviour appropriately. The identified developmental/predictive relationship is valid in both mentalistic and teleological interpretation of early communicative development.     

The strategic role of public relations in creating the competitive advantages of private higher education in Poland: The example of the school of banking in Poznan´

The aim of this article is to demonstrate the key role of public relations in increasing the competitive advantages of higher education institutions. It identifies and describes the mechanism of the shift in interest from advertising to public relations that results from the increasing complexity of the environment of a private higher education institution. Moreover, the authors conduct an analysis of the main target groups of public relations activities, referring to the conceptual model of the “two markets” according to which a private higher education institution “sells” access to education to potential candidates and then “sells” its graduates on the labour market. The practical example of the marketing and public relations activities undertaken by the authors at the School of Banking in Poznan´ since 1994 are presented and elucidated.     

Ground reaction forces and knee mechanics in the weight acceptance phase of a dance leap take-off and landing

Aesthetic constraints allow dancers fewer technique modifications than other athletes to negotiate the demands of leaping. We examined vertical ground reaction force and knee mechanics during a saut de chat performed by healthy dancers. It was hypothesized that vertical ground reaction force during landing would exceed that of take-off, resulting in greater knee extensor moments and greater knee angular stiffness. Twelve dancers (six males, six females; age 18.9 ± 1.2 years, mass 59.2 ± 9.5 kg, height 1.68 ± 0.08 m, dance training 8.9 ± 5.1 years) with no history of low back pain or lower extremity pathology participated in the study. Saut de chat data were captured using an eight-camera Vicon system and AMTI force platforms. Peak ground reaction force was 26% greater during the landing phase, but did not result in increased peak knee extensor moments. Taking into account the 67% greater knee angular displacement during landing, this resulted in less knee angular stiffness during landing. In conclusion, landing was accomplished with less knee angular stiffness despite the greater peak ground reaction force. A link between decreased joint angular stiffness and increased soft tissue injury risk has been proposed elsewhere; therefore, landing from a saut de chat may be more injurious to the knee soft tissue than take-off.     

Age and gender interactions in short distance triathlon performance

Abstract

This study investigated the participation and performance trends as well as the age and gender interaction at the Olympic distance ‘Zürich Triathlon’ (1.5?km swim, 40?km cycle and 10?km run) from 2000 to 2010 in 7,939 total finishers (1,666 females and 6,273 males). Female triathletes aged from 40 to 54 years significantly (P?<?0.05) increased their participation while the participation of younger females and males remained stable. Males of 50–54 years of age and females of 45–49 years of age improved their total race time. For elite top five overall triathletes, mean gender differences in swimming, cycling, running and overall race time were 15.2?±?4.6%, 13.4?±?2.3%, 17.1?±?2.5%, and 14.8?±?1.8%, respectively. For both elite and age group athletes, the gender difference in cycling time was significantly (P?<0.001) lower than for swimming and running. The gender difference in overall Olympic distance triathlon performance increased after the age of 35 years, which appeared earlier compared to long distance triathlon as suggested by previous studies. Future investigations should compare gender difference in performance for different endurance events across age to confirm a possible effect of exercise duration on gender difference with advancing age.