An analysis of arm movements involving forward projection of the hand in order to reach for and grasp a target at different orientations is presented. The reaching movements required shoulder flexion, elbow extension, and wrist pronation or supination. The relation between elbow and shoulder instantaneous angular position proved to be consistent from trial to trial of each task, independent of movement speed. Further, this relation was not influenced by the presence or absence of a concomitant wrist rotation. During the deceleratory phase of the movement, the slope of elbow angular velocity to shoulder angular velocity was constant and independent of target orientation. Wrist motion was instead highly variable in timing, course, and duration. Supinatory movements tended to be fractionated. On average, the duration of wrist movements was shorter than that of shoulder and elbow motions. The pattern of biceps EMG activity during supinatory and pronatory movements was different. Since motion at the shoulder and elbow was virtually identical in the two cases, net flexor torque at the elbow was also little different. It is concluded that other elbow flexors and extensors also exhibit a task-dependent patterning of activity so as to produce the same net torque. The results are discussed in the context of the internal constraints present during the movements that we examined. These constraints are the inertial coupling between shoulder and elbow motion and those which derive from the bifunctional nature of many of the muscles participating in the movement.

Lacquaniti, F., Soechting, J. (1982). Coordination of arm and wrist motion during a reaching task. THE JOURNAL OF NEUROSCIENCE, 2(4), 399-408.

Coordination of arm and wrist motion during a reaching task

LACQUANITI, FRANCESCO;
1982

Abstract

An analysis of arm movements involving forward projection of the hand in order to reach for and grasp a target at different orientations is presented. The reaching movements required shoulder flexion, elbow extension, and wrist pronation or supination. The relation between elbow and shoulder instantaneous angular position proved to be consistent from trial to trial of each task, independent of movement speed. Further, this relation was not influenced by the presence or absence of a concomitant wrist rotation. During the deceleratory phase of the movement, the slope of elbow angular velocity to shoulder angular velocity was constant and independent of target orientation. Wrist motion was instead highly variable in timing, course, and duration. Supinatory movements tended to be fractionated. On average, the duration of wrist movements was shorter than that of shoulder and elbow motions. The pattern of biceps EMG activity during supinatory and pronatory movements was different. Since motion at the shoulder and elbow was virtually identical in the two cases, net flexor torque at the elbow was also little different. It is concluded that other elbow flexors and extensors also exhibit a task-dependent patterning of activity so as to produce the same net torque. The results are discussed in the context of the internal constraints present during the movements that we examined. These constraints are the inertial coupling between shoulder and elbow motion and those which derive from the bifunctional nature of many of the muscles participating in the movement.
Pubblicato
Rilevanza internazionale
Articolo
Sì, ma tipo non specificato
Settore BIO/09
English
Con Impact Factor ISI
Elbow joint; arm; movement; forearm; electromyography; wrist; muscles; shoulder joint; humans
Lacquaniti, F., Soechting, J. (1982). Coordination of arm and wrist motion during a reaching task. THE JOURNAL OF NEUROSCIENCE, 2(4), 399-408.
Lacquaniti, F; Soechting, J
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2108/19684
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