Maximum isometric arm forces in the horizontal plane

Nijhof, Evert-Jan; Gabriel, David A.

doi:10.1016/j.jbiomech.2005.01.004

Cited by 31 publications

(21 citation statements)

References 12 publications

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“…Results showed that all values are higher than 0.89 corresponding to an elongated shape. It suggests the existence of a preferential direction of force Computer Methods in Biomechanics and Biomedical Engineering 5 application in relation to the posture in agreement with previous studies (Oshima et al 2000;Jan Nijhof and Gabriel 2006;Sasaki et al 2010). As shown in Figure 3 depicting the FE and SFE for two different elbow flexion, the main orientation is globally aligned with the longitudinal axis of the forearm.…”

Section: Discussionsupporting

confidence: 87%

Human upper-limb force capacities evaluation with robotic models for ergonomic applications: effect of elbow flexion

Hernandez

Rezzoug

Jacquier-Bret

et al. 2015

Computer Methods in Biomechanics and Biomedical Engineering

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The aim of this study was to apply models derived from the robotics field to evaluate the human upper-limb force generation capacity. Four models were compared: the force ellipsoid (FE) and force polytope (FP) based on unit joint torques and the scaled FE (SFE) and scaled FP (SFP) based on maximum isometric joint torques. The four models were assessed from four upper-limb postures with varying elbow flexion (40°, 60°, 80° and 100°) measured by an optoelectronic system and their corresponding isometric joint torques. Ten subjects were recruited. Three specific ellipsoids and polytopes parameters were compared: isotropy, principal force orientation and volume. Isotropy showed that the ellipsoids and polytopes were elongated. The angle between the two ellipsoids main axis and the two polytopes remained low but increased with the elbow flexion. The FE and FP volumes increased and those of SFE and SFP decreased with the elbow flexion. The interest and limits of such models are discussed in the framework of ergonomics and rehabilitation.

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Section: Discussionsupporting

confidence: 87%

Human upper-limb force capacities evaluation with robotic models for ergonomic applications: effect of elbow flexion

Hernandez

Rezzoug

Jacquier-Bret

et al. 2015

Computer Methods in Biomechanics and Biomedical Engineering

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“…In this case, muscle groups demonstrate synergistic effects when realizing one movement or another or under conditions of force fixation of the position of the limb (i.e., in the regimes close to isometry) [8][9][10][11][12][13][14][15][16]. As recent studies showed, the presence of relatively wide presentation of some muscles in the cortex and overlapping of the cortical zones projecting to the corresponding muscles explain possible mechanism related to production of identical motor effects (isometric efforts of different directions) by contraction of either various muscles or the same muscles but with different intensities [17][18][19][20][21].…”

Section: Introductionmentioning

confidence: 99%

Activation of the Shoulder Belt and Shoulder Muscles in Humans Providing Generation of “Two-Joint” Isometric Efforts

Верещака

2014

Neurophysiology

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This review deals with the processes of coordination of central motor commands (CMCs) that arrive at human arm muscles in the course of realization of "two-joint" voluntary isometric efforts. The dependence of formation of such motor events on changes in the direction of the generated effort is described. Differences between patterns of co-activation of the studied arm muscles under conditions of isometric contractions are presented. Based on the obtained data, directions of the developed efforts are classified as coinciding and, correspondingly, easier for realization (flexion-flexion and extensionextension in both joints), and as discordant "inconvenient" (extension in the shoulder joint-flexion in the elbow joint and flexion in the shoulder joint-extension in the elbow joint). Programming of coactivation of flexors and extensors of the shoulder and elbow joints seems to be possible at the level of CMCs. Predominant sectors of the activity of separate functional muscle groups during realization of the studied efforts are estimated. We found that the orientation of such sectors depends, in most cases, on the orientation of the effort vector but not on the position of the limb within the horizontal plane.

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“…Under static conditions (creation of isometric efforts), the control of the limb stiffness depends, to a considerable extent, on the level of tonic coactivation of the antagonist muscles, and this differentiates the above situation from the mode of realization of the movements in space, where the limb stiffness is provided within one moment or another by phasic activity of definite muscles [3,5]. Studies of the elastic properties of the shoulder belt and shoulder muscles upon changes in the position of the upper limb within the horizontal-plane operational space led to the conclusion that the value of total mechanical stiffness of the limb can change due to coordinated changes in the level of coactivation of the muscles rotating the shoulder and forearm [6,7]. At the same time, there are rather numerous data [8,9] that the above index, when the activation of the muscles influencing the elbow and shoulder joints is taken into consideration, is controlled in an independent mode.…”

Section: Introductionmentioning

confidence: 99%

Central Activation of the Upper Limb Muscles in Humans Related to Creation of an Isometric Effort: Dependence on the Position of the Point of Force Application within the Operational Space

Vereschaka

Gorkovenko

2011

Neurophysiology

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We examined the peculiarities of central coordination of motor commands coming to the muscles of the shoulder belt and shoulder in the course of generation of targeted isometric efforts by the arm. The dependence of these commands on changes in the effort direction and position of the forearm within the working space were analyzed. The intensity of the central commands was estimated according to the amplitudes of rectified and averaged EMGs recorded from the corresponding muscles. Sector diagrams of EMG activity of the above muscles depending on the direction of the effort vector, EV, were plotted [1]. Preferential sectors of activity where the efforts were formed due to activation of definite functional muscle groups were identified. As was found, the direction of these sectors depends significantly on the EV orientation. Differences between the patterns of coactivation of the examined muscles were demonstrated. Organization of the motor commands under conditions of creation of extensor efforts is distinguished by a more complex pattern than that related to flexor efforts. In the former case, the activity of extensor muscles is accompanied by more significant activation of the flexors.

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Maximum isometric arm forces in the horizontal plane

Cited by 31 publications

References 12 publications

Human upper-limb force capacities evaluation with robotic models for ergonomic applications: effect of elbow flexion

Human upper-limb force capacities evaluation with robotic models for ergonomic applications: effect of elbow flexion

Activation of the Shoulder Belt and Shoulder Muscles in Humans Providing Generation of “Two-Joint” Isometric Efforts

Central Activation of the Upper Limb Muscles in Humans Related to Creation of an Isometric Effort: Dependence on the Position of the Point of Force Application within the Operational Space

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