scholarly journals The Relationship of Maximal Strength with the Force-Velocity Profile in Resistance Trained Women

2021 ◽  
Vol 18 (5) ◽  
pp. 173-185
Author(s):  
Gergely Pálinkás ◽  
Bettina Béres ◽  
Zsófia Tróznai ◽  
Katinka Utczás ◽  
Leonidas Petridis
Keyword(s):  
Velocity Profile ◽  
Maximal Strength ◽  
Force Velocity ◽  
Relationship Of ◽  
The Relationship

Analysis of the Force-Velocity Profile in Female Ballet Dancers

2020 ◽  
Vol 24 (2) ◽  
pp. 59-65
Author(s):  
Juan Antonio Escobar Álvarez ◽  
Pedro Jiménez Reyes ◽  
Miguel Ángel Pérez Sousa ◽  
Filipe Conceição ◽  
Juan Pedro Fuentes García
Keyword(s):  
Velocity Profile ◽  
Relevant Parameter ◽  
Strength And Conditioning ◽  
Dance Performance ◽  
Jump Performance ◽  
Ballet Dancers ◽  
Dance Training ◽  
Optimal Force ◽  
Force Velocity ◽  
The Relationship

Jumping ability has been identified as one of the best predictors of dance performance. The latest findings in strength and conditioning research suggest that the relationship between force and velocity mechanical capabilities, known as the force-velocity profile, is a relevant parameter for the assessment of jumping ability. In addition, previous investigations have suggested the existence of an optimal force-velocity profile for each individual that maximizes jump performance. Given the abundance of ballistic actions in ballet (e.g., jumps and changes of direction), quantification of the mechanical variables of the force-velocity profile could be beneficial for dancers as a guide to specific training regimens that can result in improvement of either maximal force or velocity capabilities. The aim of this study was to compare the mechanical variables of the force-velocity profile during jumping in different company ranks of ballet dancers. Eighty-seven female professional ballet dancers (age: 18.94 ± 1.32 years; height: 164.41 ± 8.20 cm; weight: 56.3 ± 5.86 kg) showed high force deficits (> 40%) or low force deficits (10% to 40%) regardless of their company rank. Our results suggest that dance training mainly develops velocity capabilities, and due to the high number of dramatic elevations that dance performance requires, supplemental individualized force training may be beneficial for dancers. The individualization of training programs addressed to the direction of each individual's imbalance (high force or low force) could help dancers and their teachers to improve jump height and therefore dance performance.

Effect of bed roughness on velocity profile and water entrainment in a sedimentary density current

2018 ◽  
Vol 45 (1) ◽  
pp. 9-17 ◽  
Author(s):  
Seyed Mahmood Kashefipour ◽  
Mehdi Daryaee ◽  
Mehdi Ghomeshi
Keyword(s):  
Velocity Profile ◽  
Richardson Number ◽  
Density Current ◽  
Wall Region ◽  
Density Currents ◽  
Relative Roughness ◽  
Bed Roughness ◽  
Water Entrainment ◽  
Relationship Of ◽  
The Relationship

In this study, the effect of bed roughness on velocity profile and water entrainment in a sedimentary density current for Richardson numbers of 1.2–7 (subcritical flow conditions) was investigated. Experiments were carried out in a tilting flume with four different bed slopes, four roughness heights, and two fluid densities of sedimentary density currents. The results showed that bed roughness significantly affects the general shapes of velocity profiles, especially in the wall region. Two empirical equations were developed as the functions of the relative roughness for the wall and jet regions of velocity profile using the measured velocities of density currents. Water entrainment was also affected by bed roughness and an empirical equation was developed describing the relationship of this phenomenon with the Richardson number and relative roughness. Sensitivity analysis of this equation by using elasticity coefficient method showed that the effectiveness of the Richardson number is 3.9 times more than the effect of relative roughness on water entrainment.

Three‐dimensional velocity profile inversion from finite‐offset scattering data

Geophysics ◽  
1981 ◽  
Vol 46 (6) ◽  
pp. 837-842 ◽  
Author(s):  
S. Raz
Keyword(s):  
Velocity Profile ◽  
Three Dimensional ◽  
Scattering Data ◽  
One Dimensional ◽  
Velocity Variations ◽  
Profile Inversion ◽  
Relationship Of ◽  
The Relationship

The reconstruction of three‐dimensional (3-D) velocity variations from finite‐offset scattering data is formulated. Reduction to the limiting cases of zero and small offset distances as well as the case of one‐dimensional (1-D) stratification is given. An inherent increase in complexity is cited and interpreted. The relationship of the proposed inversion to the F-K migration is discussed.

scholarly journals The Influence of Sprint Mechanical Properties on Change of Direction in Female Futsal Players

2021 ◽  
Vol 79 (1) ◽  
pp. 221-228
Author(s):  
Andrés Baena-Raya ◽  
Dolores García-Ortega ◽  
Sergio Sánchez-López ◽  
Alberto Soriano-Maldonado ◽  
Pedro Jiménez- Reyes ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Body Height ◽  
Force Production ◽  
Maximum Velocity ◽  
Test Results ◽  
Change Of Direction ◽  
Force Velocity ◽  
Relationship Of ◽  
The Relationship ◽  
Spearman’S Correlation

Abstract The aim of the present study was to analyze the association of the sprint force-velocity profile [Hzt FV profile] variables with change of direction [COD] performance in female futsal players. Twelve female futsal players (age: 19.83 ± 4.2 years; body height: 160.75 ± 8.37 cm; body mass: 57.64 ± 8.3 kg) volunteered to be evaluated in the following assessments: Hzt FV profile, 505 test, modified 505 test [M505test] and V-cut test. The Spearman’s correlation coefficient [rs] (p < 0.05) was used to determine the relationship of the mechanical variables of the sprint (maximum power output [Pmax], maximum horizontal force production [F0] and maximum velocity [V0]) with COD performance. V0 showed a very large significant association with the 505 test (rs = -0.767; 90% CI: (-0.92 to -0.43); p < 0.01) and a large association with the V-cut test (rs = -0.641; 90% CI: (-0.86 to -0.21); p < 0.05), whereas Pmax was strongly associated with results of the 505 test (rs = -0.821; 90% CI: (-0.94 to -0.55); p < 0.01) and largely associated with the V-cut test results (rs = -0.596; 90% CI: (-0.84 to -0.14); p < 0.05). In conclusion, maximal power and velocity output during sprinting are determinant factors to successful COD in 180º and 45º cuts, thus, the Hzt FV profile should be assessed in female futsal players to better understand the influence of sprint mechanical properties on COD performance and prescribe individualized training programs

Study on Power Generation Experiment Using the Ferriferous Oxide Magnetic Fluid

2012 ◽  
Vol 562-564 ◽  
pp. 273-276 ◽  
Author(s):  
Shuang Yan Xu ◽  
Ming Jun Li
Keyword(s):  
Power Generation ◽  
Magnetic Fluid ◽  
Electromotive Force ◽  
High Efficiency ◽  
Internal Resistance ◽  
Test Fluid ◽  
Force Velocity ◽  
Set Up ◽  
Relationship Of ◽  
The Relationship

Recently, MHD is a high-efficiency and non-pollution technology. In Xiangtan University a power generation experimental set-up using the ferriferous oxide magnetic fluid in which we use the electrometer instead of external load to directly measure the electromotive force of the test magnetic fluid in the tube is established to investigate the relationship of the variables of the test fluid and the performance of the power generation. Based on the setup proposed by Hiroshi Yamaguchi in Japan, we create an experimental set-up using a new idea. Furthermore, the electromotive force and internal resistance which the magnetic fluid in the tube generates decrease with the temperature, and the electromotive force increases with the velocity of the magnetic fluid, in other words, it increases with the Reynolds number, which is in good agree with the theoretical analysis. We have also showed the image of the electromotive force, velocity and the temperature, which has helped to develop the power generation.

The relationship of the scleractinian corals to the rugose corals

Paleobiology ◽  
1980 ◽  
Vol 6 (02) ◽  
pp. 146-160 ◽  
Author(s):  
William A. Oliver
Keyword(s):  
Critical Points ◽  
Scleractinian Corals ◽  
Convincing Evidence ◽  
Early Triassic ◽  
Rugose Corals ◽  
History Of ◽  
The Subject ◽  
Relationship Of ◽  
The Relationship ◽  
Biologic Factors

The Mesozoic-Cenozoic coral Order Scleractinia has been suggested to have originated or evolved (1) by direct descent from the Paleozoic Order Rugosa or (2) by the development of a skeleton in members of one of the anemone groups that probably have existed throughout Phanerozoic time. In spite of much work on the subject, advocates of the direct descent hypothesis have failed to find convincing evidence of this relationship. Critical points are:(1) Rugosan septal insertion is serial; Scleractinian insertion is cyclic; no intermediate stages have been demonstrated. Apparent intermediates are Scleractinia having bilateral cyclic insertion or teratological Rugosa.(2) There is convincing evidence that the skeletons of many Rugosa were calcitic and none are known to be or to have been aragonitic. In contrast, the skeletons of all living Scleractinia are aragonitic and there is evidence that fossil Scleractinia were aragonitic also. The mineralogic difference is almost certainly due to intrinsic biologic factors.(3) No early Triassic corals of either group are known. This fact is not compelling (by itself) but is important in connection with points 1 and 2, because, given direct descent, both changes took place during this only stage in the history of the two groups in which there are no known corals.

Skeletal elements of crinoid echinoderms: High-resolution structural and microanalytical results

1983 ◽  
Vol 41 ◽  
pp. 194-195
Author(s):  
D. F. Blake ◽  
L. F. Allard ◽  
D. R. Peacor
Keyword(s):  
High Resolution ◽  
Marine Invertebrates ◽  
Sea Urchins ◽  
Structural Features ◽  
Sea Stars ◽  
High Resolution Tem ◽  
Relationship Of ◽  
The Relationship ◽  
Insight Into

Echinodermata is a phylum of marine invertebrates which has been extant since Cambrian time (c.a. 500 m.y. before the present). Modern examples of echinoderms include sea urchins, sea stars, and sea lilies (crinoids). The endoskeletons of echinoderms are composed of plates or ossicles (Fig. 1) which are with few exceptions, porous, single crystals of high-magnesian calcite. Despite their single crystal nature, fracture surfaces do not exhibit the near-perfect {10.4} cleavage characteristic of inorganic calcite. This paradoxical mix of biogenic and inorganic features has prompted much recent work on echinoderm skeletal crystallography. Furthermore, fossil echinoderm hard parts comprise a volumetrically significant portion of some marine limestones sequences. The ultrastructural and microchemical characterization of modern skeletal material should lend insight into: 1). The nature of the biogenic processes involved, for example, the relationship of Mg heterogeneity to morphological and structural features in modern echinoderm material, and 2). The nature of the diagenetic changes undergone by their ancient, fossilized counterparts. In this study, high resolution TEM (HRTEM), high voltage TEM (HVTEM), and STEM microanalysis are used to characterize tha ultrastructural and microchemical composition of skeletal elements of the modern crinoid Neocrinus blakei.

Studies on Leukemogenic and Sarcomagenic Viruses

1970 ◽  
Vol 28 ◽  
pp. 156-157
Author(s):  
Leon Dmochowski
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Morphological Properties ◽  
Mode Of Development ◽  
Relationship Of ◽  
The Relationship

Electron microscopy has proved to be an invaluable discipline in studies on the relationship of viruses to the origin of leukemia, sarcoma, and other types of tumors in animals and man. The successful cell-free transmission of leukemia and sarcoma in mice, rats, hamsters, and cats, interpreted as due to a virus or viruses, was proved to be due to a virus on the basis of electron microscope studies. These studies demonstrated that all the types of neoplasia in animals of the species examined are produced by a virus of certain characteristic morphological properties similar, if not identical, in the mode of development in all types of neoplasia in animals, as shown in Fig. 1.

The relationship of IGE receptor topography to signaling activity in RBL-2H3 mast cells

1991 ◽  
Vol 49 ◽  
pp. 236-237
Author(s):  
J.R. Pfeiffer ◽  
J.C. Seagrave ◽  
C. Wofsy ◽  
J.M. Oliver
Keyword(s):  
Mast Cells ◽  
Protein A ◽  
Scattered Electron ◽  
Ige Receptor ◽  
Receptor Complexes ◽  
Ige Binding ◽  
Electron Imaging ◽  
Small Clusters ◽  
Relationship Of ◽  
The Relationship

In RBL-2H3 rat leukemic mast cells, crosslinking IgE-receptor complexes with anti-IgE antibody leads to degranulation. Receptor crosslinking also stimulates the redistribution of receptors on the cell surface, a process that can be observed by labeling the anti-IgE with 15 nm protein A-gold particles as described in Stump et al. (1989), followed by back-scattered electron imaging (BEI) in the scanning electron microscope. We report that anti-IgE binding stimulates the redistribution of IgE-receptor complexes at 37“C from a dispersed topography (singlets and doublets; S/D) to distributions dominated sequentially by short chains, small clusters and large aggregates of crosslinked receptors. These patterns can be observed (Figure 1), quantified (Figure 2) and analyzed statistically. Cells incubated with 1 μg/ml anti-IgE, a concentration that stimulates maximum net secretion, redistribute receptors as far as chains and small clusters during a 15 min incubation period. At 3 and 10 μg/ml anti-IgE, net secretion is reduced and the majority of receptors redistribute rapidly into clusters and large aggregates.

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