THE INFLUENCE OF SELECTED BODY DIMENSIONAL PARAMETERS ON THE MECHANICAL PARAMETERS OF THE VERTICAL JUMP

INTRODUCTION: The purpose of the present study was to determine the influence of body fat, as well as selected limb lengths and proportions, on the maximal mechanical power and height of the countermovement jump. The effect of countermovement depth, body mass and jump height on maximal power, known from our previous study, was taken into consideration as well. METHODS: Untrained physical education students (56 female and 38 male) volunteered to take part in the CMJ jumping test, consisting of 3 jumps of different countermovement depths performed at one-minute intervals on a computerized Kistler force plate. Results of the highest jump were selected for each subject for further processing. The following variables were included in the statistical analysis: the maximal mechanical power (Pmax) developed during take-off, the height of the jump (h), the counter-movement depth (d), body mass (m) and height (H), lengths of the foot (F), shank (S), leg (L), trunk (T), shank to leg length ratio (s) and fat mass. The Shapiro-Wilk test was used to examine the distributions of the tested variables. Pearson’s correlation matrix and multiple regression analysis were employed to identify the relationships between the tested variables. RESULTS AND CONCLUSIONS: In both female and male groups the multiple regression procedure (the forward stepwise method) pointed the height of the jump, the countermovement depth and the body mass as variables having an effect on maximal power. Significant effects of the fat mass and the shank-to-leg length ratio on the height of jumps were found. REFERENCES: Aura, O., Viitasalo, J. T. (1989). Biomechanical Characteristics of Jumping. Intertional Journal of Sport Biomechanics 5, 89-98. Bobbert, M. F., Gerritsen, K. G. M., Litjens, M. C. A., Van Soest, A. J. (1995). Explanation of Differences in Jump Height Between Countermovement and Squat Jumps. Book of Abstracts. XV ISB Congress. Jyväskylä Dowling, J. J., Vamos, L. (1993). Identification of Kinetic and Temporal Factors Related to Vertical Jump Performance. J. Appl. Biomech. 9, 95-110. Harley, R. A., Doust, J. H. (1994). Effects of Different Degrees of Knee Flexion During Continuous Vertical Jumping on Power Output Using the Bosco Formula. Journal of Sports Sciences 12, 2, 139-140. Gajewski, J., Janiak, J., Eliasz, J., Wit, A. (1996). Determinants of the Maximal Mechanical Power Developed During the Countermovement Jump. In J. Abrantes (Ed.), XIV International Symposium on Biomechanics in Sports (pp.420-423). Lisbon

THE MAXIMAL MUSCLE TORQUES DISTRIBUTION AMONG MUSCLE GROUPS IN ELITE ATHLETES IN COMBAT SPORTS

INTRODUCTION: The purpose of the study was to point out typical asymmetries in strength distribution among main muscle groups in top athletes representing various kinds of combat sports. The differences in strength between tested groups were also considered and discussed. METHODS: Three groups of high-level sportsmen (11 fencers, 16 judokas and 16 boxers) took part in the experiment. Maximal muscle torques were measured in isometric conditions for flexion and extension in the elbow, shoulder, knee and hip joints for the left and right extremity. Special torquemeter devices (chair and bench) were utilized for measurement. The 2-way MACNOVA for repeated measures (8 variables) was employed to test differences in average strength between sports and sides. The logarithm of the body mass was included as a covariate. The Kolmogorov-Smirnov test was used to examine the distributions of the tested variables. RESULTS AND CONCLUSIONS: Statistical analysis revealed significant differences in average strength for both analyzed factors: sports (Rao's R=7.34,), sides (Rao's R=10.66, ) and their interaction (Rao's R=1.86, ). The asymmetrical strength distribution is thought to be the result of specific training methods applied in each tested sport discipline. The tested groups differed in strength in elbow, knee and hip for both flexion and extension. No matter how the body mass influence was controlled, the strength in the group of boxers was found lower, especially for knee and hip extensions. Fig.1. Mean values of maximal muscle torques for elbow (E), arm (A), knee (K), and hip (H) flexion (F) and extension (E) estimated for the athletes representing fencing, judo and boxing

A comparative analysis of electronic freight exchanges in the United States and Europe with the use of the multiple criteria decision-making method “promethee”

Purpose: The main purpose of this article is to conduct a comparative analysis of the electronic freight exchanges in the United States and in Europe by means of multiple criteria decision making (MCDM) method Promethee. Design/Methodology/Approach: MCDM Promethee method with the use of secondary data based on industry and branch reports from Europe and the United States as well as available statistical data and the analysis of relevant literature. The article is addressed, both to EFEs providers as well as their users. Findings: On the market of European and American open electronic freight exchanges there is a dispersed entity structure that promotes the occurrence of price competition. The differences, however, relate in particular to the number of users, geographic domination within the markets served, the period and nature of cooperation and the motives for its implementation, the integration of users' IT systems and the role of freight exchange operators in the construction and functioning of the supply chain. Practical Implications: The indication of the fundamental differences between European and American exchanges, which comprise the area for further improvements. Research limitations: The analysis is based on secondary data. No possibility of obtaining primary data from the largest players on the market of electronic freight exchanges in Europe and the USA, which constitute confidential business information Originality/value: tool development with the use of MCDM method for a comparative analysis of electronic freight exchanges. The tool can support electronic freight exchanges in the identification of strengths and weaknesses of their services as well as can be used in the process of formulation of their development strategies.peer-reviewe

Enzymatic Activity of CD73 Modulates Invasion of Gliomas via Epithelial–Mesenchymal Transition-Like Reprogramming

Glioblastoma (GBM) is the most aggressive malignant primary brain tumour in adulthood. Despite strong research efforts current treatment options have a limited impact on glioma stem-like cells (GSCs) which contribute to GBM formation, progression and chemoresistance. Invasive growth of GSCs is in part associated with epithelial–mesenchymal-like transition (EMT), a mechanism associated with CD73 in several cancers. Here, we show that CD73 regulates the EMT activator SNAIL1 and further investigate the role of enzymatic and non-enzymatic CD73 activity in GBM progression. Reduction of CD73 protein resulted in significant suppression of GSC viability, proliferation and clonogenicity, whereas CD73 enzymatic activity exhibited negative effects only on GSC invasion involving impaired downstream adenosine (ADO) signalling. Furthermore, application of phosphodiesterase inhibitor pentoxifylline, a potent immunomodulator, effectively inhibited ZEB1 and CD73 expression and significantly decreased viability, clonogenicity, and invasion of GSC in vitro cultures. Given the involvement of adenosine and A3 adenosine receptor in GSC invasion, we investigated the effect of the pharmacological inhibition of A3AR on GSC maintenance. Direct A3AR inhibition promoted apoptotic cell death and impaired the clonogenicity of GSC cultures. Taken together, our data indicate that CD73 is an exciting novel target in GBM therapy. Moreover, pharmacological interference, resulting in disturbed ADO signalling, provides new opportunities to innovate GBM therapy

The Polish Society of Gynecologists and Obstetricians Guideline for the diagnostic assessment and management of multiple-gestation pregnancy complicated by fetal growth restriction

The aim of the Guideline is to unify the diagnostic-therapeutic management of multiple-gestation pregnancies complicated by fetal growth restriction in at least one fetus.The aim of the Guideline is to unify the diagnostic-therapeuticmanagement of multiple-gestation pregnanciescomplicated by fetal growth restriction in at least one fetus