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EN
Study aim: the purpose of the study was to compare foot shapes in early school-age boys and girls. Material and methods: the study included 90 boys and 98 girls aged seven to nine years old. The shape of the foot arch was examined using a podoscope. The longitudinal arch was assessed according to the Clarke angle value on the basis of Kasperczyk’s classification. The transverse arch was assessed according to the Wejsflog index. An analysis of variance, a post-hoc LSD test and a chi-square test were performed. Results: normal transverse arches in both feet appeared in 84% of the examined children. An analysis of the average value of the Wejsflog index showed that it is similar and within limits in all of the test groups indiscriminately when it comes to gender and age. Normally, longitudinal arches in both feet occurr in 44% of children. The average value of Clarke’s index in a test group of school-age girls was within normal range while a functionally flattened foot appeared in the case of seven and eight-year-old boys. Conclusions: the outcomes of the present study conducted on a randomly chosen group of developing boys and girls show that changes in foot structure are mostly symmetrical in nature (almost 90%), meaning that if the left foot is normal, the right one is normal, too. Gender had no effect on the foot build or arch type in either foot. The right and left feet showed symmetrical structure in the majority of the children.
EN
Introduction. Distance running performance is a simple function of developing high speeds and maintaining this speed as long as possible. Thus a correct running technique becomes an important component of performance. Technique is effective if the competitor can reach a better performance result with the same or lower energy consumption. The purpose of this investigation was to examine a six weeks application explosive type strength training on lower extremities power and maximum speed performance improvement in order to facilitate running technique in sub-elite male middle-distance runner. Material and methods. A sub-elite runner performed twice a week special exercises and running drills. He completed a pre and post-training jumping (SJ, CMJ, standing long jump, standing five jump) and speed (20 m from standing and flying start) field tests. For kinematical analysis, a video (SIMI Motion System) of a 10 m sprint from a 20 m flying start was collected. Results. Improvement occurred in all measurements but strong changes were evident in the 10 m from 20 flying start and in stride frequency from 3.90 to 4.01 Hz, due to decreasing of ground contact time from 160 to 156 ms. No strong evidence in the participant's running technique changes. Conclusion. This proved that six weeks of dynamic type strength program seems to improve neuromuscular characteristics of running speed and explosive power and no changes in running technique.
EN
The purpose of the study was to analyze the parameters of the autocorrelation function when assessing time series ground reaction force (GRF) signals during quiet standing. GRF in the three directions were recorded on two Kistler force plates during three 15-s trials in a sample of 82 (31 females and 51 males) participants. Autocorrelation was performed on the GRF data and four parameters characterizing the function were computed. Comparisons of the right- and left-foot parameter means showed significant differences in mediolateral GRF for the time of the function's decay to 0, magnitude of the derivative output, and mean decay velocity to the extremum. Significant correlations were observed among all parameters – weak correlations between the time of the function's decay to 0 and the time to the first extremum and strong correlations between the derivative output and mean decay velocity to the extremum. The analyzed autocorrelation function parameters can serve as a precise measure of the motor control process during quiet standing. The strong correlations observed between the four parameters indicate that they evaluate similar properties of the central nervous system as a regulator of balance maintenance.
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