Efficient control of arm movements in advanced age
- 30 August 2006
- journal article
- clinical trial
- Published by Springer Science and Business Media LLC in Experimental Brain Research
- Vol. 177 (1), 78-94
- https://doi.org/10.1007/s00221-006-0648-7
Abstract
The present study addresses the influence of aging on the ability to regulate mechanical effects arising during arm movements due to the multi-joint structure of the arm. Two mechanical factors were considered, interaction torque (IT) and inertial resistance (IR). Regulation of these two factors can be demanding in terms of the timing and magnitude of the required muscle torque (MT), specifically during fast movements. We hypothesized that aging exacerbates the challenge regarding the regulation of these effects with muscular control due to declines in the motor system. This hypothesis was tested by comparing performance of a cyclic line-drawing task in two age groups, young and older adults. Only two joints, the shoulder and elbow, participated in motion. Four orientations of the lines were used to provide variations in the requirements for regulation of IT and IR. Cyclic frequency was manipulated to emphasize the dependence of the mechanical factors on movement speed. Various characteristics of fingertip motion showed that there were no age-related deteriorations in accuracy of line drawing. However, older adults were systematically slower, particularly in the directions of high IR. A detailed analysis of the magnitude of MT and the contribution of this torque to production of net torque at each joint demonstrated that older adults modified joint control and decreased the demands for MT by skillful exploitation of IT in a way specific for each particular line orientation. The results point to a tendency in older adults to decrease the production of muscle force. Nevertheless, older adults also demonstrated an ability to partially compensate for declines in the force production by developing sophisticated strategies of joint control that exploit the multi-joint mechanical structure of the arm. This ability suggests that the internal representation of inter-segmental dynamics and the capability to use it for movement control does not decay with age. The study emphasizes the importance of analysis of joint motion and control characteristics for the investigation of arm movements and for comparison of these movements between different subject populations.Keywords
This publication has 72 references indexed in Scilit:
- Circle-Drawing Movements at Different Speeds: Role of Inertial AnisotropyJournal of Neurophysiology, 2002
- Prism adaptation in normal aging: slower adaptation rate and larger aftereffectCognitive Brain Research, 2000
- Feedforward postural adjustments in a simple two-joint synergy in patients with Parkinson's diseaseElectroencephalography and Clinical Neurophysiology/Electromyography and Motor Control, 1995
- Age-Related Differences in the Control of Spatial Aiming MovementsResearch Quarterly for Exercise and Sport, 1992
- Mobility impairment in the elderly: Challenges for biomechanics researchJournal of Biomechanics, 1992
- Dynamical Aspects of Learning an Interlimb Rhythmic Movement PatternJournal of Motor Behavior, 1992
- Age differences in the maintenance and restructuring of movement preparation.Psychology and Aging, 1991
- Kinematics of arm movements in elderly humansNeurobiology of Aging, 1989
- Movement specification time with ageExperimental Aging Research, 1987
- Adult age differences in the speed and capacity of information processing: II. An electrophysiological approach.Psychology and Aging, 1987