Changes in Multi-Joint Performance with Age

Abstract

The purpose of this study was to determine whether elderly adults exhibit deficits in the performance of multi-joint movements. Two groups of subjects (mean ages 68.9, 30.1 years respectively) participated in this experiment. Subjects performed planar arm pointing movements to various targets. One target could be achieved via elbow extension only, while the remaining three required both elbow extension and horizontal shoulder flexion, thus requiring coordination at the two joints. In contrast to the young adults, the elderly adults produced movements that became less smooth and less accurate with increasing shoulder joint contribution. The results imply a selective coordination deficit for the elderly adults. In addition, the elderly adults coactivated opposing muscles more than the young adults for the single-joint movement. The elderly adults reduced coactivation at both joints for the two-joint actions, however, while the young adults did not. These data suggest a relationship between high coactivation levels and good performance for elderly adults. It may be more difficult for the elderly to implement high coactivation levels for multi-joint movements because of the increased energy costs and complexity of planning required in comparison to the single joint actions. Thus, elderly persons appear to use coactivation in a manner that is fundamentally different than young adults to achieve motor performance.

Mentally represented motor actions in normal agingI. Age effects on the temporal features of overt and covert execution of actions

“…It is well known that aging affects human skeletal muscle structure, which, in turn, may influence muscle contraction properties in elderly people [32,46,47]. This sarcopenia, associated to neural factors, notably to the reduction in motor unit activation capacity [17,49] and to the coactivation of antagonist muscles [23,43], may account for the loss of muscle strength and power in elderly people. However, these structural and neural factors alone cannot fully explain the decline of movement speed which accompanies normal aging.…”

“…Is this ability function of the kind and difficulty of motor task being imagined? It is well known that normal aging influences cognitive functions [2,13,24,40,41] and sensorimotor control of actions [22,43,44]. The state of musculoskeletal system, in particular that of muscular mechanics and structure, is also modified [17,23,26,32,46,47,49].…”

Normal aging reduces motor synergies in manual pointing

“…Studies on rapid goal-directed arm movements found older adults to show slower and more variable arm movements than younger adults (Darling et al, 1989;Yan et al, 1998Yan et al, , 2000 and higher levels of muscle coactivation . Moreover, agerelated impairments in movement smoothness and end-point accuracy are generally more pronounced for movements requiring shoulder-elbow coordination than for single-joint actions (Seidler et al, 2002), suggesting a selective deficit in multijoint coordination among the elderly.…”

Vision for Motor Performance in Virtual Environments Across the Lifespan

“…This decrease has a physiologic basis in aging and is amplified by disuse and dysfunction. In general, aging adults demonstrate decreases in movement speed (Light, 1990;Mankovsky, Mints, & Lisenyuk, 1982;Poston et al, 2008;Yan et al, 1998), accuracy of movement (Chaput & Proteau, 1996), reaction time (Light, 1990;Sparrow et al, 2006;Yan et al, 1998), strength (Roos et al, 1997;Vandervoort, 2002), hand dexterity (Contreras-Vidal, Teulings, & Stelmach, 1998;Seidler, Alberts, & Stelmach, 2002), and postural control (Jonsson, Henriksson, & Hirschfeld, 2007;Koceja, Allway, & Earles, 1999;Mourey et al, 1998;. En masse, these changes have the potential to contribute to a spiral of disuse and loss of function that often characterizes the process of aging.…”