Search results for " jump"
showing 10 items of 171 documents
Plantar pressure and EMG activity of simulated and actual ski jumping take-off
2001
Plantar pressures and activation of the four muscles (VL - vastus lateralis, GL - gluteus, TA - tibialis anterior and GA - lat. gastrocnemius) were measured from ten ski jumpers under simulated laboratory conditions with training shoes (Lab TS) and with jumping boots (Lab JB) as well as in actual hill jumping conditions (Hill). The most significant differences between measured conditions were found in muscle activation patterns and plantar pressures prior to take-off. The centrifugal force due to the curvature of the inrun under actual hill jumping conditions caused extra pressure under the fore and rear parts of the feet (P<0.001) and therefore higher activation in all muscles (P<0.001 for…
A 47-Year Comparison of Lower Body Muscular Power in Spanish Boys: A Short Report
2020
Much of the evidence examining temporal trends in fitness among youth has found a decrease in measures of muscular strength and muscular power over recent decades. The aim of this study was to examine trends in lower body muscular power in Spanish boys over 47 years. In 1969 140 boys (10–11 years; body mass index = 19.24, SD = 2.91 kg/m2) and in 2016, 113 boys (10–11 years; body mass index = 19.20, SD = 3.15 kg/m2) were recruited. Lower body power was assessed using the vertical jump (VJ) and standing long jump (SLJ) tests. Significant differences and a large effect size were shown between groups in the SLJ (p = 0.001; d = 0.94) and the VJ (p = 0.001; d = 0.66). SLJ data in 1969 were higher…
Robust H∞ filtering for networked control systems with markovian jumps and packet dropouts
2014
Published version of an article in the journal: Modeling, Identification and Control. Also available from the publisher at: http://dx.doi.org/10.4173/mic.2014.3.3 Open Access This paper deals with the H∞ filtering problem for uncertain networked control systems. In the study, network-induced delays, limited communication capacity due to signal quantization and packet dropout are all taken into consideration. The finite distributed delays with probability of occurrence in a random way is introduced in the network.The packet dropout is described by a Bernoulli process. The system is modeled as Markovian jumps system with partially known transition probabilities. A full-order filter is designe…
Cytogenetic characterization of HB2 epithelial cells from the human breast.
2014
HB2 is a cell line originated by subcloning of MTSV1-7 mammary luminal epithelial cells isolated from human milk and immortalization via introduction of the gene encoding simian virus 40 (SV40) large T antigen. Despite its wide utilization as non-neoplastic counterpart in assays aimed to elucidating various biochemical and genetical aspects of normal and tumoral breast cells, to our knowledge no literature data have so far appeared concerning the chromosomal characterization of the HB2 cells. Here, we report the cytogenetic characterization of the karyotype of HB2 cells, which puts in evidence the occurrence of changes in chromosomal number and structure and the presence of unidentified chr…
Two-Leg Squat Jumps in Water: An Effective Alternative to Dry Land Jumps
2009
The current study was designed to quantify and compare the kinetic parameters of two-leg squat jumps carried out on dry land, in water and in water using area devices that increase drag force. Twelve junior female handball players who had been competing at national level for the previous two years volunteered to participate in the study. Intensity of the two-leg squat jump was examined using a force plate (9 253-B11, Kistler Instrument AG, Winterthur, Switzerland) in three different conditions: on dry land, in water and in water using devices. An ANOVA with repeated measurements (condition) was applied to establish differences between the three jumps. The results show that peak impact force…
Validity and Reliability of a Single Question for Leisure-Time Physical Activity Assessment in Middle-Aged Women.
2020
Purpose: To investigate the validity and test–retest reliability of a single seven-level scale physical activity assessment question (SR-PA L7) and its three-level categorization (SR-PA C3). Methods: The associations of SR-PA L7 and C3 with accelerometer-measured leisure-time physical activity (ACC-LTPA) and with the results of four different physical performance tests (6-min walk [n = 733], knee extension [n = 695], vertical jump [n = 731], and grip force [n = 780]) were investigated among women aged 47–55 years participating in the Estrogenic Regulation of Muscle Apoptosis study (n = 795). The reliability was studied using Spearman correlations with 4-month test–retest period (n = 152). R…
Aerodynamics of an isolated ski jumping ski
2019
A single isolated ski was suspended from a six-component wind tunnel balance and three angles, the angle of attack, the yaw angle and the edge angle were adjustable during the test. Increasing yaw angle from 0 to 15° increased the lift coefficient CL from 0.42 to 0.90 at edge angle 0° and from 0.70 to 0.87 at edge angle 10°, respectively. Increasing yaw angle also increased the sensitivity of the ski to changes in edge angle, i.e., increasing the edge angle (20°–45°) decreased the CL and the ratio $$C_{L}^{2}/{C_D}$$ with large yaw angles. However, to maximize the lift-to-drag ratio with a typical angle of attack of 30° in ski jumping, it may be reasonable to have an edge angle of 5°–10° on…
Finite-time boundedness for uncertain discrete neural networks with time-delays and Markovian jumps
2014
This paper is concerned with stochastic finite-time boundedness analysis for a class of uncertain discrete-time neural networks with Markovian jump parameters and time-delays. The concepts of stochastic finite-time stability and stochastic finite-time boundedness are first given for neural networks. Then, applying the Lyapunov approach and the linear matrix inequality technique, sufficient criteria on stochastic finite-time boundedness are provided for the class of nominal or uncertain discrete-time neural networks with Markovian jump parameters and time-delays. It is shown that the derived conditions are characterized in terms of the solution to these linear matrix inequalities. Finally, n…
Validity of Hip-worn Inertial Measurement Unit Compared to Jump Mat for Jump Height Measurement in Adolescents
2018
Jump tests assess lower body power production capacity, and can be used to evaluate athletic ability and development during growth. Wearable inertial measurement units (IMU) seem to offer a feasible alternative to laboratory-based equipment for jump height assessments. Concurrent validity of these devices for jump height assessments has only been established in adults. Therefore, the purpose of this study was to evaluate the concurrent validity of IMU-based jump height estimate compared to contact mat-based jump height estimate in adolescents. Ninety-five adolescents (10-13 years-of-age; girls N = 41, height = 154 (SD 9) cm, weight = 44 (11) kg; boys N = 54, height = 156 (10) cm, weight = 4…
On-Ice and Off-Ice Fitness Profiles of Elite and U20 Male Ice Hockey Players of Two Different National Standards
2020
Vigh-Larsen, JF, Haverinen, MT, Panduro, J, Ermidis, G, Andersen, TB, Overgaard, K, Krustrup, P, Parkkari, J, Avela, J, Kyröläinen, H, and Mohr, M. On-ice and off-ice fitness profiles of elite and U20 male ice hockey players of two different national standards. J Strength Cond Res 34(12): 3369-3376, 2020-Differences in body composition and performance were investigated between elite and U20 male ice hockey players of 2 different national standards. One hundred seventy-nine players were recruited from the highest Finnish (n = 82) and Danish (n = 61) national level, as well as from 1 U20 team from Finland (n = 19) and Denmark (n = 17). Body composition and countermovement jump performance (CM…