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Slobodan Jaric - One of the best experts on this subject based on the ideXlab platform.
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is test standardization important when arm and leg muscle mechanical properties are assessed through the force velocity relationship
Journal of Human Kinetics, 2019Co-Authors: Marko Cosic, Slobodan Jaric, Aleksandar Nedeljkovic, Sasa Djuric, Milena Z Zivkovic, Bojan LeontijevicAbstract:The force-velocity (F-V) relationship observed in multi-Joint Tasks proved to be strong and approximately linear. Recent studies showed that mechanical properties of muscles: force (F), velocity (V) and power (P) could be assessed through the F-V relationship although the testing methods have not been standardized. The aim of the present study was to evaluate and compare F-V relationships assessed from two tests performed on a modified Smith machine that standardizes kinematics of the movement pattern. Fifteen participants were tested on the maximum performance bench press throws and squat jumps performed against a variety of different loads. In addition, their strength properties were assessed through maximum isometric force (Fiso) and one repetition maximum (1 RM). The observed individual F-V relationships were exceptionally strong and approximately linear (r = 0.98 for bench press throws; r = 0.99 for squat jumps). F-V relationship parameter depicting maximum force (F0) revealed high correlations with both Fiso and 1 RM indicating high concurrent validity (p < 0.01). However, the generalizability of F-V relationship parameters depicting maximum force (F0), velocity (V0) and power (P0) of the tested muscle groups was inconsistent and on average low (i.e. F0; r = -0.24) to moderate (i.e. V0 and P0; r = 0.54 and r = 0.64, respectively; both p < 0.05). We concluded that the F-V relationship could be used for the assessment of arm and leg muscle mechanical properties when standard tests are applied, since the typical outcome is an exceptionally strong and linear F-V relationship, as well as high concurrent validity of its parameters. However, muscle mechanical properties could be only partially generalized across different tests and muscles.
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selective effects of different fatigue protocols on the function of upper body muscles assessed through the force velocity relationship
European Journal of Applied Physiology, 2018Co-Authors: Amador Garciaramos, Paulino Padial, Belen Feriche, Alejandro Torrejon, Antonio J Moralesartacho, Alejandro Perezcastilla, Slobodan JaricAbstract: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. 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. In the non-failure protocols, participants performed half the maximum number of repetitions than in their respective failure protocols. The main findings revealed that (1) all F–V relationships were highly linear (median r = 0.997 and r = 0.982 for averaged across participants and individual data, respectively), (2) the fatiguing protocols were ranked based on the magnitude of power loss as follows: 60%1RM failure > 80%1RM failure > 60%1RM non-failure > 80%1RM non-failure, while (3) the assessed maximum force and velocity outputs showed a particularly prominent reduction in the protocols based on the lowest and highest levels of fatigue (i.e., 80%1RM non-failure and 60%1RM failure), respectively. The results support the use of F–V to assess the effects of fatigue on the distinctive capacities of the muscles to produce force, velocity, and power output while performing multi-Joint Tasks, while the assessed maximum force and velocity capacities showed a particularly prominent reduction in the protocols based on the lowest and highest levels of fatigue (i.e., 80%1RM non-failure and 60%1RM failure), respectively.
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evaluation of force velocity and power velocity relationship of arm muscles
European Journal of Applied Physiology, 2015Co-Authors: Sreten Sreckovic, Aleksandar Nedeljkovic, Sasa Djuric, Ivan Cuk, Dragan M Mirkov, Slobodan JaricAbstract:A number of recent studies have revealed an approximately linear force–velocity (F–V) and, consequently, a parabolic power–velocity (P–V) relationship of multi-Joint Tasks. However, the measurement characteristics of their parameters have been neglected, particularly those regarding arm muscles, which could be a problem for using the linear F–V model in both research and routine testing. Therefore, the aims of the present study were to evaluate the strength, shape, reliability, and concurrent validity of the F–V relationship of arm muscles. Twelve healthy participants performed maximum bench press throws against loads ranging from 20 to 70 % of their maximum strength, and linear regression model was applied on the obtained range of F and V data. One-repetition maximum bench press and medicine ball throw tests were also conducted. The observed individual F–V relationships were exceptionally strong (r = 0.96–0.99; all P 0.80), while their concurrent validity regarding directly measured F, P, and V ranged from high (for maximum F) to medium-to-low (for maximum P and V). The findings add to the evidence that the linear F–V and, consequently, parabolic P–V models could be used to study the mechanical properties of muscular systems, as well as to design a relatively simple, reliable, and ecologically valid routine test of the muscle ability of force, power, and velocity production.
C D Frith - One of the best experts on this subject based on the ideXlab platform.
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coming to terms quantifying the benefits of linguistic coordination
Psychological Science, 2012Co-Authors: Riccardo Fusaroli, Bahador Bahrami, Karsten Olsen, Andreas Roepstorff, Geraint Rees, C D FrithAbstract:Sharing a public language facilitates particularly efficient forms of Joint perception and action by giving interlocutors refined tools for directing attention and aligning conceptual models and action. We hypothesized that interlocutors who flexibly align their linguistic practices and converge on a shared language will improve their cooperative performance on Joint Tasks. To test this prediction, we employed a novel experimental design, in which pairs of participants cooperated linguistically to solve a perceptual task. We found that dyad members generally showed a high propensity to adapt to each other's linguistic practices. However, although general linguistic alignment did not have a positive effect on performance, the alignment of particular task-relevant vocabularies strongly correlated with collective performance. In other words, the more dyad members selectively aligned linguistic tools fit for the task, the better they performed. Our work thus uncovers the interplay between social dynamics and sensitivity to task affordances in successful cooperation.
Bahador Bahrami - One of the best experts on this subject based on the ideXlab platform.
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coming to terms quantifying the benefits of linguistic coordination
Psychological Science, 2012Co-Authors: Riccardo Fusaroli, Bahador Bahrami, Karsten Olsen, Andreas Roepstorff, Geraint Rees, C D FrithAbstract:Sharing a public language facilitates particularly efficient forms of Joint perception and action by giving interlocutors refined tools for directing attention and aligning conceptual models and action. We hypothesized that interlocutors who flexibly align their linguistic practices and converge on a shared language will improve their cooperative performance on Joint Tasks. To test this prediction, we employed a novel experimental design, in which pairs of participants cooperated linguistically to solve a perceptual task. We found that dyad members generally showed a high propensity to adapt to each other's linguistic practices. However, although general linguistic alignment did not have a positive effect on performance, the alignment of particular task-relevant vocabularies strongly correlated with collective performance. In other words, the more dyad members selectively aligned linguistic tools fit for the task, the better they performed. Our work thus uncovers the interplay between social dynamics and sensitivity to task affordances in successful cooperation.
Tim Miller - One of the best experts on this subject based on the ideXlab platform.
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communication in human agent teams for Tasks with Joint action
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 2016Co-Authors: Weixing Sun, Tim MillerAbstract:© Springer International Publishing Switzerland 2016. In many scenarios, humans must team with agents to achieve Joint aims. When working collectively in a team of human and artificial agents, communication is important to establish a shared situation of the task at hand. With no human in the loop and little cost for communication, information about the task can be easily exchanged. However, when communication becomes expensive, or when there are humans in the loop, the strategy for sharing information must be carefully designed: too little information leads to lack of shared situation awareness, while too much overloads the human team members, decreasing performance overall. This paper investigates the effects of sharing beliefs and goals in agent teams and in human-agent teams. We performed a set of experiments using the BlocksWorlds for Teams (BW4T) testbed to assess different strategies for information sharing. In previous experimental studies using BW4T, explanations about agent behaviour were shown to have no effect on team performance. One possible reason for this is because the existing scenarios in BW4T contained Joint Tasks, but not Joint actions. That is, atomic actions that required interdependent and simultaneous action between more than one agent. We implemented new scenarios in BW4T in which some actions required two agents to complete. Our results showed an improvement in artificial-agent team performance when communicating goals and sharing beliefs, but with goals contributing more to team performance, and that in human-agent teams, communicating only goals was more effective than communicating both goals and beliefs.
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communication in human agent teams for Tasks with Joint action
Coordination Organizations Institutions and Norms in Agent Systems, 2015Co-Authors: Weixing Sun, Tim MillerAbstract:In many scenarios, humans must team with agents to achieve Joint aims. When working collectively in a team of human and artificial agents, communication is important to establish a shared situation of the task at hand. With no human in the loop and little cost for communication, information about the task can be easily exchanged. However, when communication becomes expensive, or when there are humans in the loop, the strategy for sharing information must be carefully designed: too little information leads to lack of shared situation awareness, while too much overloads the human team members, decreasing performance overall. This paper investigates the effects of sharing beliefs and goals in agent teams and in human-agent teams. We performed a set of experiments using the BlocksWorlds for Teams (BW4T) testbed to assess different strategies for information sharing. In previous experimental studies using BW4T, explanations about agent behaviour were shown to have no effect on team performance. One possible reason for this is because the existing scenarios in BW4T contained Joint Tasks, but not Joint actions. That is, atomic actions that required interdependent and simultaneous action between more than one agent. We implemented new scenarios in BW4T in which some actions required two agents to complete. Our results showed an improvement in artificial-agent team performance when communicating goals and sharing beliefs, but with goals contributing more to team performance, and that in human-agent teams, communicating only goals was more effective than communicating both goals and beliefs.
Alan Kingstone - One of the best experts on this subject based on the ideXlab platform.
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Labor division in Joint Tasks: Humans maximize use of their individual attentional capacities
Attention Perception & Psychophysics, 2020Co-Authors: Basil Wahn, Alan KingstoneAbstract:In daily life, humans frequently perform visuospatial Tasks together (e.g., visual search) and distribute the labor in such Tasks. Previous research has shown that humans prefer a left and right labor division in a Joint multiple object tracking (MOT) task. Yet, findings from studies investigating individuals’ tracking ability suggest attentional capacities may be more maximally used with a top and bottom labor division. We investigated whether co-actors’ labor division preference is influenced by how they are seated (neighboring vs. opposite of each other) or how the MOT task is displayed (portrait vs. landscape). We find that pairs attain a higher performance using a top and bottom labor division and preferred this labor division compared to a left and right division. This preference was unaffected by the seating arrangement. For the landscape display, however, we find that participants no longer attain a higher performance for the top and bottom labor division and accordingly participants’ preference for this labor division was greatly reduced as well. Overall, we propose that co-actors are sensitive to changes within their environment, which allows them to choose a labor division that maximizes use of their individual attentional capacities.
