scholarly journals Relación entre la potencia y velocidad en press de banca y la velocidad de lanzamiento de balón en jugadores profesionales de balonmano (Relationship between barbell power and velocity in bench press exercise and ball throwing velocity in professional ha

Retos ◽  
2020 ◽  
pp. 53-59
Author(s):  
Iker Javier Bautista ◽  
Juan Vicente-Mampel ◽  
Luis Baraja-Vegas ◽  
Isidoro Martínez
Keyword(s):  
Bench Press ◽  
Average Power ◽  
Mean Velocity ◽  
Specific Performance ◽  
Relevant Variables ◽  
The Mean ◽  
Incremental Protocol ◽  
The One ◽  
The Relationship ◽  
Correlation Range

 Los objetivos de este estudio fueron (a) analizar la relación existente entre la una repetición máxima (1-RM) en press de banca y la velocidad de lanzamiento en jugadores de balonmano U18 de nivel internacional y, (b) analizar qué variables del ejercicio del press de banca son más relevantes en el rendimiento específico (velocidad de lanzamiento del balón) durante el test de velocidad de lanzamiento (T3-Step). Dieciséis jugadores de la Selección Española de Balonmano Juvenil participaron en la presente investigación. Todos los sujetos realizaron un protocolo incremental en el ejercicio del press de banca, además del T3-Step de velocidad de lanzamiento del balón. Por un lado, se analizó la relación existente entre la velocidad media (Velmedia), velocidad media de la fase propulsiva (VelMFP), velocidad pico (Velpico), potencia media (Potmedia), potencia media de la fase propulsiva (PotMFP), y potencia pico (Potpico) en todo el espectro de cargas en relación con la velocidad de lanzamiento. También se realizaron los mismos análisis con la carga en donde se obtuvo la máxima potencia media (CargaMP). Los resultados mostraron, por un lado que el rango de correlación de la CargaMP, PotmediaMP, PotMFPMP y PotpicoMP y la velocidad de lanzamiento fueron de .61 (p= .012), .702 (p< .01), .734 (p< .01) y .63 (p< .01), respectivamente. El coeficiente de correlación de Pearson entre la 1-RM y la velocidad de lanzamiento fue de r = .61 (p < .01). En conclusión, las variables relevantes a nivel de rendimiento específico con la velocidad de lanzamiento fueron la 1RM, la CargaMP, la PotMFPMP y la VelMFPMP. Todas estas analizadas en función del 60% de la 1-RM.  Abstract. The objectives of this study were (a) to analyze the relationship between one repetition maximum (1-RM) in free bench press exercise and ball throwing velocity in handball players U18 of international level and, (b) to analyze which variables of bench press exercise are more relevant in the specific performance during the ball throwing velocity test (T3-Step). Sixteen (n = 16) players of the Spanish Youth Handball Team participated in the present investigation. All subjects included performed an incremental protocol bench press exercise, in addition to the T3-Step. On the one hand, it analyzed the relationship between the mean velocity (Velmean), the mean velocity of propulsive phase (VelmeanPP), peak velocity (Velpeak), the average power (Powermean), the average power of the propulsive phase (PowermeanPP), and peak power (Powerpeak) over the entire spectrum of charges in relation to the launch speed. The same analyzes were also obtained with the load where the maximum average power (LoadMP). The results obtained, on the one hand that the correlation range of the LoadMP, PowermeanPP, PowerMPPMP and PowerpeakPP and ball throwing velocity were .61 (p = .012), .70 (p < .01), .73 (p < .01) and 0.63 (p < .01), respectively. The correlation coefficient between the 1-RM and ball throwing velocity was r = 0.61 (p< .01). In conclusion, the relevant variables at the specific performance level with the ball throwing velocity were 1-RM, LoadMP, PowerMFPMP and VelMFPMP. All these analyzed according to 60% of the 1-RM.

scholarly journals Validity and Reliability of a Smartphone Accelerometer for Measuring Lift Velocity in Bench-Press Exercises

2020 ◽  
Vol 12 (6) ◽  
pp. 2312
Author(s):  
Javier Peláez Barrajón ◽  
Alejandro F. San Juan
Keyword(s):  
Bench Press ◽  
Basic Program ◽  
Validity And Reliability ◽  
Training Experience ◽  
Mean Velocity ◽  
Repetition Maximum ◽  
Linear Transducer ◽  
The Mean ◽  
One Year ◽  
The One

The aim of this study was to determine the validity and reliability that a smartphone accelerometer (ACC) used by a mobile basic program (MBP) can provide to measure the mean velocity of a bench-press (BP) lift. Ten volunteers participated in the study (age 23.1 ± 2.5 years; mean ± SD). They had more than one year of resistance training experience in BP exercise. All performed three attempts with different loads: 70%, 90%, and 100% of the estimated value of the one-repetition maximum (1RM). In each repetition, the mean velocity was measured by a validated linear transducer and the ACC. The smartphone accelerometer used by the mobile basic program showed no significant differences between the mean velocities at 70% 1RM lifts (ACC = 0.52 ± 0.11 m/s; transducer = 0.54 ± 0.09 m/s, p > 0.05). However, significant differences were found in the mean velocities for 90% 1RM (ACC = 0.46 ± 0.09 m/s; transducer = 0.31 ± 0.03 m/s, p < 0.001), and 100% 1RM (ACC = 0.33 ± 0.21 m/s; transducer = 0.16 ± 0.04 m/s, p < 0.05). The accelerometer is sensitive enough to measure different lift velocities, but the algorithm must be correctly calibrated.

Toroidal plasma configuration with anisotropic pressure

1987 ◽  
Vol 38 (2) ◽  
pp. 209-222 ◽  
Author(s):  
Hussain M. Rizk
Keyword(s):  
General Expression ◽  
Magnetic Surface ◽  
Anisotropic Pressure ◽  
Mean Velocity ◽  
Magnetohydrodynamic Equation ◽  
Toroidal Plasma ◽  
Hydrodynamic Calculations ◽  
The Mean ◽  
The One ◽  
Plasma Configuration

The relation between various surface quantities required in hydrodynamic calculations, and the relation between the parallel and perpendicular currents in an arbitrary magnetic toroidal plasma configuration with scalar pressure, are generalized to the case of anisotropic pressure. Magnetic co-ordinates for hydrodynamic equilibria in this configuration are defined. A general expression for the mean velocity of diffusion through a magnetic surface, on the basis of the one-fluid magnetohydrodynamic equation with anisotropic pressure, is derived.

The Effect of Waking Suggestion on Post-Hypnotic Amnesia

1981 ◽  
Vol 11 (1) ◽  
pp. 44-46 ◽  
Author(s):  
D.P. Fourie
Keyword(s):  
Point Of View ◽  
The Other ◽  
Hypnotic Susceptibility ◽  
The Subject ◽  
The Mean ◽  
The Difference ◽  
The One ◽  
The Relationship ◽  
Female Subjects

It is increasingly realized that hypnosis may be seen from an interpersonal point of view, meaning that it forms part of the relationship between the hypnotist and the subject. From this premise it follows that what goes on in the relationship prior to hypnosis probably has an influence on the hypnosis. Certain of these prior occurences can then be seen as waking suggestionns (however implicitly given) that the subject should behave in a certain way with regard to the subsequent hypnosis. A study was conducted to test the hypothesis that waking suggestions regarding post-hypnotic amnesia are effective. Eighteen female subjects were randomly divided into two groups. The groups listened to a tape-recorded talk on hypnosis in which for the one group amnesia for the subsequent hypnotic experience and for the other group no such amnesia was suggested. Thereafter the Stanford Hypnotic Susceptibility Scale was administered to all subjects. Only the interrogation part of the amnesia item of the scale was administered. The subjects to whom post-hypnotic amnesia was suggested tended to score lower on the amnesia item than the other subjects, as was expected, but the difference between the mean amnesia scores of the two groups was not significant.

Prediction of the Maximum Number of Repetitions and Repetitions in Reserve From Barbell Velocity

2018 ◽  
Vol 13 (3) ◽  
pp. 353-359 ◽  
Author(s):  
Amador García-Ramos ◽  
Alejandro Torrejón ◽  
Belén Feriche ◽  
Antonio J. Morales-Artacho ◽  
Alejandro Pérez-Castilla ◽  
...  
Keyword(s):  
Body Mass ◽  
General Equation ◽  
Bench Press ◽  
Body Height ◽  
Strong Relationship ◽  
Training Set ◽  
Mean Velocity ◽  
The Mean ◽  
Acceptable Reliability

Purpose: To provide 2 general equations to estimate the maximum possible number of repetitions (XRM) from the mean velocity (MV) of the barbell and the MV associated with a given number of repetitions in reserve, as well as to determine the between-sessions reliability of the MV associated with each XRM. Methods: After determination of the bench-press 1-repetition maximum (1RM; 1.15 ± 0.21 kg/kg body mass), 21 men (age 23.0 ± 2.7 y, body mass 72.7 ± 8.3 kg, body height 1.77 ± 0.07 m) completed 4 sets of as many repetitions as possible against relative loads of 60%1RM, 70%1RM, 80%1RM, and 90%1RM over 2 separate sessions. The different loads were tested in a randomized order with 10 min of rest between them. All repetitions were performed at the maximum intended velocity. Results: Both the general equation to predict the XRM from the fastest MV of the set (CV = 15.8–18.5%) and the general equation to predict MV associated with a given number of repetitions in reserve (CV = 14.6–28.8%) failed to provide data with acceptable between-subjects variability. However, a strong relationship (median r2 = .984) and acceptable reliability (CV < 10% and ICC > .85) were observed between the fastest MV of the set and the XRM when considering individual data. Conclusions: These results indicate that generalized group equations are not acceptable methods for estimating the XRM–MV relationship or the number of repetitions in reserve. When attempting to estimate the XRM–MV relationship, one must use individualized relationships to objectively estimate the exact number of repetitions that can be performed in a training set.

Monitoring Training Volume Through Maximal Number of Repetitions or Velocity-Based Approach

2020 ◽  
pp. 1-8
Author(s):  
Miguel Sánchez-Moreno ◽  
Gonçalo Rendeiro-Pinho ◽  
Pedro V. Mil-Homens ◽  
Fernando Pareja-Blanco
Keyword(s):  
Coefficient Of Variation ◽  
Bench Press ◽  
Interindividual Variability ◽  
Load Condition ◽  
Velocity Relationship ◽  
The Mean ◽  
Monitoring Training ◽  
The Individual ◽  
The Relationship ◽  
Level Of Effort

Purpose: This study aimed (1) to analyze the interindividual variability in the maximal number of repetitions (MNR) performed against a given relative load (percentage of 1-repetition maximum [%1RM]) and (2) to examine the relationship between the velocity loss (VL) magnitude and the percentage of completed repetitions with regard to the MNR (%Rep), when the %1RM is based on individual load–velocity relationships. Methods: Following an assessment of 1RM strength and individual load–velocity relationships, 14 resistance-trained men completed 5 MNR tests against loads of 50%, 60%, 70%, 80%, and 90% 1RM in the Smith machine bench-press exercise. The relative loads were determined from the individual load–velocity relationship. Results: Individual relationships between load and velocity displayed coefficients of determination (R2) ranging from .986 to .998. The MNR showed an interindividual coefficient of variation ranging from 8.6% to 33.1%, increasing as the %1RM increased. The relationship between %Rep and the magnitude of VL showed a general R2 of .92 to .94 between 50% and 80% 1RM, which decreased to .80 for 90% 1RM. The mean individual R2 values were between .97 and .99 for all loading conditions. The %Rep when a given percentage of VL was reached showed interindividual coefficient of variation values ranging from 5% to 20%, decreasing as the %Rep increased in each load condition. Conclusions: Setting a number of repetitions had acceptable interindividual variability, with moderate relative loads being adjusted based on the individual load–velocity relationship. However, to provide a more homogeneous level of effort between athletes, the VL approach should be considered, mainly when using individual VL–%Rep relationships.

scholarly journals Measurements and numerical simulations of snow-particle saltation

1998 ◽  
Vol 26 ◽  
pp. 184-190 ◽  
Author(s):  
K. Nishimura ◽  
K. Sugiura ◽  
M. Nemoto ◽  
N. Maeno
Keyword(s):  
Friction Velocity ◽  
Laser Sheet ◽  
Impact Angle ◽  
Wind Tunnel Experiments ◽  
Mean Velocity ◽  
Measured Probability ◽  
The Mean ◽  
Snow Particle ◽  
The Relationship ◽  
Particle Saltation

First, wind-tunnel experiments were carried out to measure the trajectories of saltating snow particles with varying friction velocity. Trajectories of saltating particles were recorded by a video system with a laser sheet and trajectory statistics, such as ejection and impact velocities and angles, were obtained for each particle. Parabolic trajectories are considerably elongated with an increase in the friction velocity; impact angle was approximately the same but ejection angle decreased with increasing friction velocity. Furthermore, it should be noted that the gradient of flux decay with height decreased with friction velocity. In the experiments, a snow-particle counter, which can sense not only the number of particles but also their diameters, was introduced. The flux distribution and the transport rate obtained as a function of the particle size gave a new insight into the relationship with the friction velocity.Trajectories of saltating grains were computed, using the measurements of the initial ejection velocities, angles and the mean velocity profile of the air. The results agreed reasonably with our measurements. Using the measured probability distribution of the ejection velocities, an ensemble of trajectories was computed and thence the vertical profiles of stream-wise fluxes. The exponential decay of the flux on height was obtained in all cases and it supports the basic validity of the model, although agreement is less than expected.

An effective, low-cost method to improve the movement velocity measurement of a smartphone app during the bench press exercise

2021 ◽  
pp. 175433712110580
Author(s):  
Wladymir Külkamp ◽  
Jairo L Rosa-Junior ◽  
Jonathan Ache-Dias ◽  
Lorival J Carminatti
Keyword(s):  
Older Adults ◽  
Velocity Measurement ◽  
Bench Press ◽  
Low Cost ◽  
Reference Method ◽  
Velocity Measurements ◽  
Range Of Movement ◽  
Mean Velocity ◽  
Movement Velocity ◽  
The Mean

Some studies have reported considerable errors in the movement velocity measurement when using the My Lift app. This study aimed to investigate whether these errors may be related to the use of a range of movement (ROM) statically measured prior to the movement (ROMMYLIFT) instead of ROM dynamically monitored. Ten young adults performed two repetitions of the bench press exercise on a Smith machine with loads that allowed two velocity conditions (above and below 0.6 m s−1). The exercises were monitored by the My Lift app, a magnet and a rotary encoder. After, 15 older adults performed the same exercise at different percentages of 1RM, monitored by the My Lift app and a magnet. The results revealed that ROM dynamically obtained by encoder (reference method) with the mean velocity above (0.497 ± 0.069 m) and below (0.450 ± 0.056 m) 0.6 m s−1 were quite different ( p < 0.05; large effect) from the ROMMYLIFT (0.385 ± 0.040 m). These errors provided highly biased and heteroscedastic mean velocity measurements (mean errors approximately 22%). The errors observed in adults were also observed in the older participants, except for loads equal to 85% of 1RM. The magnet method proved to be valid, presenting measurements very close to the encoder (mean errors approximately 1.7%; r > 0.99). In conclusion, the use of ROMMYLIFT is inadequate, as the higher the movement velocity, the higher the errors, both for young and older adults. Thus, to improve the measurement of the My Lift app, it is recommended that the magnet method be used in conjunction with the app to more accurately determine the ROM.

scholarly journals Nonlinear waves with a threefold rotational symmetry in pipe flow: influence of a strongly shear-thinning rheology

2017 ◽  
Vol 818 ◽  
pp. 595-622
Author(s):  
Emmanuel Plaut ◽  
Nicolas Roland ◽  
Chérif Nouar
Keyword(s):  
Reynolds Number ◽  
Laminar Flow ◽  
Nonlinear Waves ◽  
Pipe Flow ◽  
Rotational Symmetry ◽  
Shear Thinning ◽  
Transition To Turbulence ◽  
Mean Velocity ◽  
The Mean ◽  
The One

In order to model the transition to turbulence in pipe flow of non-Newtonian fluids, the influence of a strongly shear-thinning rheology on the travelling waves with a threefold rotational symmetry of Faisst & Eckhardt (Phys. Rev. Lett., vol. 91, 2003, 224502) and Wedin & Kerswell (J. Fluid Mech., vol. 508, 2004, pp. 333–371) is analysed. The rheological model is Carreau’s law. Besides the shear-thinning index $n_{C}$, the dimensionless characteristic time $\unicode[STIX]{x1D706}$ of the fluid is considered as the main non-Newtonian control parameter. If $\unicode[STIX]{x1D706}=0$, the fluid is Newtonian. In the relevant limit $\unicode[STIX]{x1D706}\rightarrow +\infty$, the fluid approaches a power-law behaviour. The laminar base flows are first characterized. To compute the nonlinear waves, a Petrov–Galerkin code is used, with continuation methods, starting from the Newtonian case. The axial wavenumber is optimized and the critical waves appearing at minimal values of the Reynolds number $\mathit{Re}_{w}$ based on the mean velocity and wall viscosity are characterized. As $\unicode[STIX]{x1D706}$ increases, these correspond to a constant value of the Reynolds number based on the mean velocity and viscosity. This viscosity, close to the one of the laminar flow, can be estimated analytically. Therefore the experimentally relevant critical Reynolds number $\mathit{Re}_{wc}$ can also be estimated analytically. This Reynolds number may be viewed as a lower estimate of the Reynolds number for the transition to developed turbulence. This demonstrates a quantified stabilizing effect of the shear-thinning rheology. Finally, the increase of the pressure gradient in waves, as compared to the one in the laminar flow with the same mass flux, is calculated, and a kind of ‘drag reduction effect’ is found.

scholarly journals Relationship between files that bind at the apical foramen and foramen openings in maxillary central incisors - a SEM study

2011 ◽  
Vol 22 (6) ◽  
pp. 455-459 ◽  
Author(s):  
Ronaldo Araújo Souza ◽  
Yara T. Corrêa Silva Sousa ◽  
José Antônio Poli de Figueiredo ◽  
João Da Costa Pinto Dantas ◽  
Suely Colombo ◽  
...  
Keyword(s):  
Microscopic Analysis ◽  
Electron Microscopic ◽  
Significant Difference ◽  
Sem Study ◽  
Scanning Electron Microscopic ◽  
Scanning Electron Microscopic Analysis ◽  
The Mean ◽  
The One ◽  
Foraminal Area ◽  
The Relationship

Considering that instrumentation of the apical foramen has been suggested for root canal infection control, this study analyzed the relationship between the files that bind at the apical foramen and the foraminal openings in 50 maxillary central incisors. After preparation of the pulp chamber, access to the canal was obtained with #1 and 2 LA Axxess and K-files with tip cut were inserted up to the apical foramen until binding was felt. The files were fixed with methyl cyanoacrylate and the tooth-file sets were cross-sectioned 10 mm short of the apex. Scanning electron microscopic analysis was carried out and files and foraminal areas were measured using Image Tool software. Statistically significant difference (p<0.0001) was found between files and the apical foraminal areas. The mean foraminal area was 3.8 times larger than the mean file area. The results of this study suggest that it would require 4 files of greater size beyond the one that bound to the foramen in order to allow a better relationship between files and apical openings of maxillary central incisors.

Forward and Backward Running Waves in the Arteries: Analysis Using the Method of Characteristics

1990 ◽  
Vol 112 (3) ◽  
pp. 322-326 ◽  
Author(s):  
K. H. Parker ◽  
C. J. H. Jones
Keyword(s):  
Transient Flow ◽  
Impedance Analysis ◽  
Time Domain Analysis ◽  
Mean Velocity ◽  
One Dimensional ◽  
Acceleration And Deceleration ◽  
The Mean ◽  
The One ◽  
Made In

The one-dimensional equations of flow in the elastic arteries are hyperbolic and admit nonlinear, wavelike solutions for the mean velocity, U, and the pressure, P. Neglecting dissipation, the solutions can be written in terms of wavelets defined as differences of the Riemann invariants across characteristics. This analysis shows that the product, dUdP, is positive definite for forward running wavelets and negative definite for backward running wavelets allowing the determination of the net magnitude and direction of propagating wavelets from pressure and velocity measured at a point in the artery. With the linearizing assumption that intersecting wavelets are additive, the forward and backward running wavelets can be separately calculated. This analysis, applied to measurements made in the ascending aorta of man, shows that forward running wavelets dominate during both the acceleration and deceleration phases of blood flow in the aorta. The forward and backward running waves calculated using the linearized analysis are similar to the results of an impedance analysis of the data. Unlike the impedance analysis, however, this is a time domain analysis which can be applied to nonperiodic or transient flow.

Sign in / Sign up

Export Citation Format

Share Document