THE INFLUENCE OF THE ELEVATION OF THE LANDING PLACE ON THE EXECUTION OF THE BACKWARD SOMERSAULT

INTRODUCTION: To improve performance in gymnastics free exercise, various specific methods are employed. One method used with the backward somersault is to employ an elevated landing place. According to some sport practitioners, such a change of conditions should evoke a greater effort by athletes during takeoff, and the resulting general center of gravity (GCG) path during the flight phase should be higher. The aim of this paper was to identify kinematic parameters which changed under various conditions, and which remained unchanged, when using various heights of landing surface for the backward somersault. METHODS: The experiment was carried out with five experienced athletes who were leading European competitors. Each subject performed backward somersaults, landing on a landing place elevated at foru different heights: 0.08, 0.24, 0.40 and 0.48 meter. The experiments were recorded with a 50 Hz video camera. Two-dimensional kinematic analysis of all somersaults yielded the parameters which described how the motor task was accomplished. Average values of of the chosen parameters were calculated, along with standard deviations. Relative angles in the shoulder, knee and hip joints were measured at chosen moments, as well as the trajectory of the general center of gravity of the body and maximum height of the flight. Average values of the parameters under consideration were calculated from among 15 trials (3 trials made by each of the 5 subjects). The data obtained for each of the elevations of the landing place were compared. RESULTS: The employment of an elevated landing place as a measure for evoking greater effort on the part of the competitor during the trial did not result in a change of kinematic parameters during the main phase of the motion. The final part of the motion changed significantly, however. The higher landing place caused the competitor to land in a very inconvenient position, which made keeping of balance more difficult. This forced him to choose another way of landing. It can be concluded that the exercise might be accepted as a technique for the improvement of landing technique only, but it does not significantly influence the performance of the main part of the backward somersault. REFERENCES: Gwizdek, I. (1993). Zum Einsatz spezielle Trainingsmittel im motorischen Lernprozess des Gerätturnens unter besonderer Berücksichtigung der Entwicklung der Abdruckfähigkeit. In G.-P. Brüggemann, J.K. Rühl (Eds.), Biomechanik im Turmen [Biomechanics in Gymnastics], proceedings of First International Conference, September 8-10, Köln, Germany, pp. 379 - 385. Król, H. (1993). Wplyw pozycji startowej na przebieg ruchu w konkurencji podnoszenia ciezarow - rwanie [Influence of Starting Position of the Course of the Movement in a Weight Lifting Competition - a Snatch]. ANTROPOMOTORYKA , 10, 127 -136. Król, H. (1997). Kinematyka kroku plotkowego w zaleznosci od wysokosci plotka [The Kinematics of the Hurdle Stride at Different Heights of the Hurdle]. ANTROPOMOTORYKA, 16 16, 103-111

EVALUATION OF RELIABILITY AND CONCURRENT VALIDITY OF INEXPENSIVE AND EXPENSIVE SYSTEMS USED FOR RECORDING MAXIMUM VERTICAL JUMP PERFORMANCE

The reliability and validity of two alternative systems used for jumping performance measurement was evaluated. Two groups of subjects consisted of 15 male adults and the 16 female volleyball players. We used three different systems of data collection: Optojump Next (optoelectric) referred as the inexpensive system, BTS Smart-E (motion capture) as the expensive system. Concurrent validity of these systems was checked with the use of standard force platform. All systems were used to estimate the height of vertical jumps. Both systems showed highly reliability with the ICCs=0.98 for Optojump and 0.90 for BTS Smart. Their concurrent validity with the force platform data was also very high r=0.99 and r=0.97 respectively. Comparison of these two systems demonstrated distinct differences between the two systems: Optojump system is more suitable for quick and reliable sports testing

THE BIOELECTRIC ACTIVITY OF MUSCLE PECTORALIS MAJOR IN PRESSING FROM A LYING POSITION

The bioelectric activity of muscle pectoralis major was recorded with the help of surface EMG. The aim of this work was to determine participation of three parts of this muscle in motor task realization i.e. the pressing of a barbell in a lying position. Despite a suitable competitors’ selection (the first class) and a similar way of task realization (the 'bridge' technique) some competitors indicated a large activity in central part of the muscle whereas the others in lower or upper part. Average bioelectric activity of three parts of muscle together, in all subjects, was larger in pressing phase than in lowering phase during the press in a lying position. It may mean, that the way of trial realization is also affected by other factors, i.e. the radius of “bridge” curvature or trajectory motion of barbell

Quality determinants of organizational safety

PURPOSE: The article shows the quality conditions of organisation security in various areas, including the development, implementation, maintenance, improvement and auditing of the quality management system based on the ISO 9001 standard, taking into account soft and hard quality improvement factors in the organisation.DESIGN/METHODOLOGY/APPROACH: The purpose of this research was to identify the areas of qualitative activity that affect the stability of the organisation's development and thus its security. The theoretical and cognitive goal was a substantive review of the literature on the subject and scientific studies in the field of quality management in the sense of stable development. The research goal was to identify barriers and limitations in the area of development and achievement of quality goals. The authors analysed and assessed the quality management system in the organisation in three aspects, development and implementation, maintenance and improvement, and audit.FINDINGS: The process of developing, implementing, maintaining, improving and auditing the quality management system affects the security level of the organisation. Owing to that, it is a modern tool focusing on introducing organisational order in the company, both in terms of structure and creativity of all employees.PRACTICAL IMPLICATIONS: The article identifies the qualitative security of the organisation activities and processes supporting business activities. The authors addressed this topic in the context of the culture of quality, security and excellence.ORIGINALITY/VALUE: The authors present the quality management system as a modern and effective quality improvement tool that requires many activities and far-reaching changes, which brings undeniable benefits in the organisational and economic sphere. The culture of quality, security and excellence as well as the employees are the foundation for the effective and efficient implementation of quality management concepts, models of excellence and specific pro-quality approaches, for the development of the organisation and managing the multidimensional risk of its functioning.peer-reviewe

The influence of some xanthone derivatives on the activity of J-774A.1 cells

The chemiluminescence of stimulated cells with phorbol myristate acetate and the production of nitric oxide after stimulation with lipopolisaccharide in the presence of the parent compounds FAA (flavone-8-acetic acid = (4-oxo-2- phenyl-4H-chromen-8-yl)acetic acid), XAA (xanthone-4-acetic acid = (9-oxo-9Hxanthen-4-yl)acetic acid), and appropriate xanthone derivatives (1-7) was determined. Also the toxicity of the FAA, MFAA ((6-methyl-4-oxo-2-aryl-4Hchromen-8-yl)acetic acid), XAA and 1–7 against J-774A.1 cultured cells was evaluated. Compound 5 (2-methyl-2-{[(9-oxo-9H-xanthen-2-yl)methyl]sulfanyl}- propanoic acid) was effective in inhibiting chemiluminescence of J-774A.1 cells but most of the other tested compounds stimulated the reaction. FAA and two xanthones with a methoxycarbonyl moeity slightly decreased the generation of nitric oxide at 50 μM. Most of the tested compounds (1-7) showed weak toxicity at concentration of 100 μM

The gene expression profiles of canine mammary cancer cells grown with carcinoma-associated fibroblasts (CAFs) as a co-culture in vitro

<p>Abstract</p> <p>Background</p> <p>It is supposed that fibroblasts present in tumour microenvironment increase cancer invasiveness and its ability to metastasize but the mechanisms have not been clearly defined yet. Thus, the current study was designed to assess changes in gene expression in five various cancer cell lines grown as a co-culture with the carcinoma-associated fibroblasts (CAFs) <it>in vitro</it>.</p> <p>Results</p> <p>A carcinoma-associated fibroblast cell line was isolated from a canine mammary cancer. Then, a co-culture of cancer cells with the CAFs was established and maintained for 72 hrs. Having sorted the cells, a global gene expression in cancer cells using DNA microarrays was examined. The analysis revealed an up-regulation of 100 genes and a down-regulation of 106 genes in the cancer cells grown as a co-culture with the CAFs in comparison to control conditions. The PANTHER binomial statistics tool was applied to determine statistically over-manifested pathways (<it>p </it>< 0.05). Bulk of the up-regulated genes are involved in the adhesion, the angiogenesis, the epithelial-mesenchymal transition (EMT) and generally take part in the developmental processes. These results were further confirmed using real-time qPCR. Moreover, a wound-healing assay and growth characteristics on Matrigel matrix showed that CAFs increase cancer cell migration and matrix invasion.</p> <p>Conclusion</p> <p>The results of the current study showed that the co-culturing of cancer cells and the CAFs caused significant changes to the cancer gene expression. The presence of the CAFs in a microenvironment of cancer cells promotes adhesion, angiogenesis and EMT.</p