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Force-velocity

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https://www.readbyqxmd.com/read/29339982/relationships-between-mechanical-variables-in-the-traditional-and-close-grip-bench-press
#1
Robert G Lockie, Samuel J Callaghan, Matthew R Moreno, Fabrice G Risso, Tricia M Liu, Alyssa A Stage, Samantha A Birmingham-Babauta, John J Stokes, Dominic V Giuliano, Adrina Lazar, DeShaun L Davis, Ashley J Orjalo
The study aim was to determine relationships between mechanical variables in the one-repetition maximum (1RM) traditional bench press (TBP) and close-grip bench press (CGBP). Twenty resistance-trained men completed a TBP and CGBP 1RM. The TBP was performed with the preferred grip; the CGBP with a grip width of 95% biacromial distance. A linear position transducer measured: lift distance and duration; work; and peak and mean power, velocity, and force. Paired samples t-tests (p < 0.05) compared the 1RM and mechanical variables for the TBP and CGBP; effect sizes (d) were also calculated...
December 2017: Journal of Human Kinetics
https://www.readbyqxmd.com/read/29302753/a-comparison-between-the-force-velocity-relationships-of-unloaded-and-sled-resisted-sprinting-single-vs-multiple-trial-methods
#2
Matt R Cross, Pierre Samozino, Scott R Brown, Jean-Benoît Morin
PURPOSE: We sought to compare force-velocity relationships developed from unloaded sprinting acceleration to that compiled from multiple sled-resisted sprints. METHODS: Twenty-seven mixed-code athletes performed six to seven maximal sprints, unloaded and towing a sled (20-120% of body-mass), while measured using a sports radar. Two methods were used to draw force-velocity relationships for each athlete: A multiple trial method compiling kinetic data using pre-determined friction coefficients and aerodynamic drag at maximum velocity from each sprint; and a validated single trial method plotting external force due to acceleration and aerodynamic drag and velocity throughout an acceleration phase of an unloaded sprint (only)...
January 4, 2018: European Journal of Applied Physiology
https://www.readbyqxmd.com/read/29289151/construction-of-non-markovian-coarse-grained-models-employing-the-mori-zwanzig-formalism-and-iterative-boltzmann-inversion
#3
Yuta Yoshimoto, Zhen Li, Ikuya Kinefuchi, George Em Karniadakis
We propose a new coarse-grained (CG) molecular simulation technique based on the Mori-Zwanzig (MZ) formalism along with the iterative Boltzmann inversion (IBI). Non-Markovian dissipative particle dynamics (NMDPD) taking into account memory effects is derived in a pairwise interaction form from the MZ-guided generalized Langevin equation. It is based on the introduction of auxiliary variables that allow for the replacement of a non-Markovian equation with a Markovian one in a higher dimensional space. We demonstrate that the NMDPD model exploiting MZ-guided memory kernels can successfully reproduce the dynamic properties such as the mean square displacement and velocity autocorrelation function of a Lennard-Jones system, as long as the memory kernels are appropriately evaluated based on the Volterra integral equation using the force-velocity and velocity-velocity correlations...
December 28, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/29284062/effects-of-cross-bridge-compliance-on-the-force-velocity-relationship-and-muscle-power-output
#4
Axel J Fenwick, Alexander M Wood, Bertrand C W Tanner
Muscles produce force and power by utilizing chemical energy through ATP hydrolysis. During concentric contractions (shortening), muscles generate less force compared to isometric contractions, but consume greater amounts of energy as shortening velocity increases. Conversely, more force is generated and less energy is consumed during eccentric muscle contractions (lengthening). This relationship between force, energy use, and the velocity of contraction has important implications for understanding muscle efficiency, but the molecular mechanisms underlying this behavior remain poorly understood...
2017: PloS One
https://www.readbyqxmd.com/read/29281133/the-impact-of-strength-level-on-adaptations-to-combined-weightlifting-plyometric-and-ballistic-training
#5
Lachlan P James, G Gregory Haff, Vincent G Kelly, Mark Connick, Ben Hoffman, Emma M Beckman
The purpose of this investigation was to determine if the magnitude of adaptation to integrated ballistic training is influenced by initial strength level. Such information is needed to inform resistance training guidelines for both higher- and lower-level athlete populations. To this end, two groups of distinctly different strength levels (stronger: one-repetition-maximum (1RM) squat = 2.01 ± 0.15 kg. BM-1 ; weaker: 1.20 ± 0.20 kg. BM-1 ) completed 10 weeks of resistance training incorporating weightlifting derivatives, plyometric actions and ballistic exercises...
December 27, 2017: Scandinavian Journal of Medicine & Science in Sports
https://www.readbyqxmd.com/read/29262355/regulation-of-contraction-by-the-thick-filaments-in%C3%A2-skeletal-muscle
#6
REVIEW
Malcolm Irving
Contraction of skeletal muscle cells is initiated by a well-known signaling pathway. An action potential in a motor nerve triggers an action potential in a muscle cell membrane, a transient increase of intracellular calcium concentration, binding of calcium to troponin in the actin-containing thin filaments, and a structural change in the thin filaments that allows myosin motors from the thick filaments to bind to actin and generate force. This calcium/thin filament mediated pathway provides the "START" signal for contraction, but it is argued that the functional response of the muscle cell, including the speed of its contraction and relaxation, adaptation to the external load, and the metabolic cost of contraction is largely determined by additional mechanisms...
December 19, 2017: Biophysical Journal
https://www.readbyqxmd.com/read/29242994/selective-effects-of-different-fatigue-protocols-on-the-function-of-upper-body-muscles-assessed-through-the-force-velocity-relationship
#7
Amador García-Ramos, Alejandro Torrejón, Belén Feriche, Antonio J Morales-Artacho, Alejandro Pérez-Castilla, Paulino Padial, Slobodan Jaric
PURPOSE: This study explored the feasibility of the force-velocity relationship (F-V) to detect the acute effects of different fatigue protocols on the selective changes of the maximal capacities of upper body muscles to produce force, velocity, and power. METHODS: After determining the bench press one-repetition maximum (1RM), participants' F-V relationships were assessed during the bench press throw exercise on five separate sessions after performing one of the following fatiguing protocols: 60%1RM failure, 60%1RM non-failure, 80%1RM failure, 80%1RM non-failure, and no-fatigue...
December 14, 2017: European Journal of Applied Physiology
https://www.readbyqxmd.com/read/29199778/influence-of-ethnicity-on-vertical-jump-performances-in-male-physical-education-students-a-pilot-study
#8
Elvis Attiogbe, Henry Vandewalle, Tarak Driss
BACKGROUND: The present study aimed to: i) test the possibility of ethnic differences in squat jump (SJ), countermovement jump (CMJ) and countermovement jump with arms swing (CMJA); ii) test the possibility of ethnic differences in the effects of countermovement and arms swing; iii) verify whether the relationships between the different vertical jumps VJ (SJ, CMJ, CMJA) and maximal power (Pmax), determined from a force-velocity test (F-V), were dependent on the ethnicity as previously found for CMJA...
December 1, 2017: Journal of Sports Medicine and Physical Fitness
https://www.readbyqxmd.com/read/29129132/reliability-of-force-velocity-relationships-during-deadlift-high-pull
#9
Wei Lu, Sébastien Boyas, Marc Jubeau, Abderrahmane Rahmani
This study aimed to evaluate the within- and between-session reliability of force, velocity and power performances and to assess the force-velocity relationship during the deadlift high pull (DHP). Nine participants performed two identical sessions of DHP with loads ranging from 30 to 70% of body mass. The force was measured by a force plate under the participants' feet. The velocity of the 'body + lifted mass' system was calculated by integrating the acceleration and the power was calculated as the product of force and velocity...
November 13, 2017: Sports Biomechanics
https://www.readbyqxmd.com/read/29126339/the-force-velocity-relationship-in-older-people-reliability-and-validity-of-a-systematic-procedure
#10
Julian Alcazar, Carlos Rodriguez-Lopez, Ignacio Ara, Ana Alfaro-Acha, Asier Mañas-Bote, Amelia Guadalupe-Grau, Francisco Jose García-García, Luis M Alegre
This study compared the reliability and validity of different protocols evaluating the force-velocity (F-V) relationship and muscle power in older adults. Thirty-one older men and women (75.8±4.7 years) underwent two F-V tests by collecting the mean and peak force and velocity data exerted against increasing loads until one repetition maximum (1RM) was achieved in the leg press exercise. Two attempts per load were performed, with a third attempt when F-V points deviated from the linear F-V regression equation...
November 10, 2017: International Journal of Sports Medicine
https://www.readbyqxmd.com/read/29125040/reliability-of-horizontal-force-velocity-power-profiling-during-short-sprint-running-accelerations-using-radar-technology
#11
Kim David Simperingham, John B Cronin, Simon N Pearson, Angus Ross
Radar technology can be used to perform horizontal force-velocity-power profiling during sprint-running. The aim of this study was to determine the reliability of radar-derived profiling results from short sprint accelerations. Twenty-seven participants completed three 30 m sprints (intra-day analysis), and nine participants completed the testing session on four separate days (inter-day analysis). The majority of radar-derived kinematic and kinetic descriptors of short sprint performance had acceptable intra-day and inter-day reliability [intraclass correlation coefficient (ICC) ≥ 0...
November 10, 2017: Sports Biomechanics
https://www.readbyqxmd.com/read/29101912/effect-of-hip-joint-angle-on-concentric-knee-extension-torque
#12
Ryoichi Ema, Taku Wakahara, Yasuo Kawakami
This study tested the hypothesis that the effect of hip joint angle on concentric knee extension torque depends on knee joint angle during a single knee extension task. Twelve men performed concentric knee extensions in fully extended and 80° flexed hip positions with maximal effort. The angular velocities were set at 30° s(-1) and 180° s(-1). The peak torque and torques attained at 30°, 50°, 70° and 90° (anatomical position = 0°) of the knee joint were compared between the two hip positions...
October 26, 2017: Journal of Electromyography and Kinesiology
https://www.readbyqxmd.com/read/29093684/porcine-stomach-smooth-muscle-force-depends-on-history-effects
#13
André Tomalka, Mischa Borsdorf, Markus Böl, Tobias Siebert
The stomach serves as food reservoir, mixing organ and absorption area for certain substances, while continually varying its position and size. Large dimensional changes during ingestion and gastric emptying of the stomach are associated with large changes in smooth muscle length. These length changes might induce history-effects, namely force depression (FD) following active muscle shortening and force enhancement (FE) following active muscle stretch. Both effects have impact on the force generating capacity of the stomach, and thus functional relevance...
2017: Frontiers in Physiology
https://www.readbyqxmd.com/read/29089109/explosive-lower-limb-extension-mechanics-an-on-land-vs-in-water-exploratory-comparison
#14
Brice Guignard, Jessy Lauer, Pierre Samozino, Luis Mourão, João Paulo Vilas-Boas, Annie Hélène Rouard
During a horizontal underwater push-off, performance is strongly limited by the presence of water, inducing resistances due to its dense and viscous nature. At the same time, aquatic environments offer a support to the swimmer with the hydrostatic buoyancy counteracting the effects of gravity. Squat jump is a vertical terrestrial push-off with a maximal lower limb extension limited by the gravity force, which attracts the body to the ground. Following this observation, we characterized the effects of environment (water vs...
October 25, 2017: Journal of Biomechanics
https://www.readbyqxmd.com/read/29076192/regional-variation-in-the-mechanical-properties-and-fibre-type-composition-of-the-rat-extensor-digitorum-longus-muscle
#15
Roger W P Kissane, Stuart Egginton, Graham N Askew
Fibre type composition is heterogeneous and distribution varies spatially in many muscles, indicating there may be regional variation in recruitment and mechanical output. The rat extensor digitorum longus muscle is composed of predominantly fast-twitch fibres, and exhibits a gradient in phenotype, resulting in oxidative medial (areal composition 24.3% Type I/IIa) and glycolytic lateral (92.4% Type IIx/IIb) compartments. Here, we investigated the variation in mechanical performance between the medial and lateral compartments during isometric, isotonic and cyclical contractions...
October 26, 2017: Experimental Physiology
https://www.readbyqxmd.com/read/29050041/lower-limb-force-velocity-power-capabilities-during-leg-press-and-squat-movements
#16
Johnny Padulo, Gian Mario Migliaccio, Luca Paolo Ardigò, Bruno Leban, Marco Cosso, Pierre Samozino
The aim was to compare lower-limb power, force, and velocity capabilities between squat and leg press movements. Ten healthy sportsmen performed ballistic lower-limb push-offs against 5-to-12 different loads during both the squat and leg press. Individual linear force-velocity and polynomial power-velocity relationships were determined for both movements from push-off mean force and velocity measured continuously with a pressure sensor and linear encoder. Maximal power output, theoretical maximal force and velocity, force-velocity profile and optimal velocity were computed...
October 19, 2017: International Journal of Sports Medicine
https://www.readbyqxmd.com/read/28976526/cooperative-behavior-of-biased-probes-in-crowded-interacting-systems
#17
Oleg A Vasilyev, Olivier Bénichou, Carlos Mejía-Monasterio, Eric R Weeks, Gleb Oshanin
We study, via extensive numerical simulations, dynamics of a crowded mixture of mutually interacting (with a short-range repulsive potential) colloidal particles immersed in a suspending solvent, acting as a heat bath. The mixture consists of a majority component - neutrally buoyant colloids subject to internal stimuli only, and a minority component - biased probes (BPs) also subject to a constant force. In such a system each of the BPs alters the distribution of the colloidal particles in its vicinity, driving their spatial distribution out of equilibrium...
October 25, 2017: Soft Matter
https://www.readbyqxmd.com/read/28972685/effects-of-manipulating-tetanic-calcium-on-the-curvature-of-the-force-velocity-relationship-in-isolated-rat-soleus-muscles
#18
A M Kristensen, O B Nielsen, K Overgaard
AIM: In dynamically contracting muscles, increased curvature of the force-velocity relationship contributes to the loss of power during fatigue. It has been proposed that fatigue-induced reduction in [Ca(++) ]i causes this increased curvature. However, earlier studies on single fibers have been conducted at low temperatures. Here, we investigated the hypothesis that curvature is increased by reductions in tetanic [Ca(++) ]i in isolated skeletal muscle at near-physiological temperatures...
October 3, 2017: Acta Physiologica
https://www.readbyqxmd.com/read/28965345/relationship-between-force-velocity-profiles-and-1-500-m-ergometer-performance-in-young-rowers
#19
Caroline Giroux, Hugo Maciejewski, Amal Ben-Abdessamie, Frédéric Chorin, Julien Lardy, Sebastien Ratel, Abderrahmane Rahmani
Rowing races require developing high level of force and power output at high contraction velocity. This study determined the force-velocity and power-velocity (F-P-V) profiles of lower and upper limbs of adolescent rowers and their relationships with a 1,500-m rowing ergometer performance. The power developed during the 1,500-m (P1500) was evaluated in fourteen national-level male rowers (age: 15.3±0.6 yrs). F-P-V profiles were assessed during bench pull (BP) and squat jump (SJ) exercises. The theoretical maximal values of force (F0), velocity (V0), power output (Pmax) and the F-V relationship slope (S FV ) were determined...
October 1, 2017: International Journal of Sports Medicine
https://www.readbyqxmd.com/read/28965339/where-does-the-one-repetition-maximum-exist-on-the-force-velocity-relationship-in-squat
#20
Jean Romain Rivière, Jérémy Rossi, Pedro Jimenez-Reyes, Jean-Benoit Morin, Pierre Samozino
The aim was to determine the position of the one-repetition maximum (1RM) squat point on the force-velocity (F-V) relationship obtained during squat jump (SJ). Ten healthy athletes performed a 1RM squat during which ground reaction force and lower-limb extension velocity were measured, and six loaded SJs to determine individual F-V relationship. The goodness of fit of the linear F-V relationship with or without the 1RM point was tested. The vertical and horizontal coordinates were determined relative to the theoretical maximal force (F0) and the highest loaded SJ (load of 44...
October 1, 2017: International Journal of Sports Medicine
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