Associations Among Strength, Steadiness, and Hand Function
Associations Among Strength, Steadiness, and Hand Function
Introduction: Age-related differences in force steadiness have been extensively examined and used as an index of motor function. However, the functional relevance of steadiness remains unclear.
Purpose: The aim here was to evaluate the relations among hand strength, steadiness, and function across the adult life span.
Methods: Seventy-five adults (45 women; 18–89 yr) performed three strength, two steadiness, and four functional tests with both hands. Strength was measured during index finger abduction, precision pinch, and handgrip, and steadiness was measured during index finger abduction and precision pinch. Functional tests included the Grooved Pegboard test, the game Operation™, a scissor task, and a tracing task.
Results: Moderate correlations were observed between both steadiness tasks and performance on the Grooved Pegboard test (R = 0.57 and R = 0.46, respectively) and Operation™ (R = −0.47 and R = −0.57, respectively).
Conclusions: The relation between measures of steadiness and hand function suggests that the physiological mechanisms responsible for differences in steadiness also contribute to differences in the performance of fine motor tasks with the hand.
The neuromuscular mechanisms responsible for the decline in motor function with advancing age have been difficult to identify because of the constraints that are necessary to obtain experimental indices of motor performance. As an index of fine motor function, for example, tests of steadiness typically require an individual to exert a constant submaximal force during an isometric contraction of an isolated muscle or group of muscles, which may have limited functional relevance. Although the fluctuations in force during such steady contractions vary with contraction type, contraction intensity, and age, few studies have examined the functional significance of these fluctuations in the force.
Furthermore, steadiness is often measured during tasks that involve few agonist and antagonist muscles, such as abduction/adduction of the index finger, so that there is a more direct association between the activation signal sent from the nervous system and the resulting mechanical output. Even the simplest everyday task, however, rarely involves such isolated actions, which begs the question of whether or not differences in the steadiness of experimental tasks are associated with differences in functional capabilities. The aim of this study was to investigate the associations among measures of strength, steadiness, and fine motor function of hand muscles across the adult life span.
Abstract and Introduction
Abstract
Introduction: Age-related differences in force steadiness have been extensively examined and used as an index of motor function. However, the functional relevance of steadiness remains unclear.
Purpose: The aim here was to evaluate the relations among hand strength, steadiness, and function across the adult life span.
Methods: Seventy-five adults (45 women; 18–89 yr) performed three strength, two steadiness, and four functional tests with both hands. Strength was measured during index finger abduction, precision pinch, and handgrip, and steadiness was measured during index finger abduction and precision pinch. Functional tests included the Grooved Pegboard test, the game Operation™, a scissor task, and a tracing task.
Results: Moderate correlations were observed between both steadiness tasks and performance on the Grooved Pegboard test (R = 0.57 and R = 0.46, respectively) and Operation™ (R = −0.47 and R = −0.57, respectively).
Conclusions: The relation between measures of steadiness and hand function suggests that the physiological mechanisms responsible for differences in steadiness also contribute to differences in the performance of fine motor tasks with the hand.
Introduction
The neuromuscular mechanisms responsible for the decline in motor function with advancing age have been difficult to identify because of the constraints that are necessary to obtain experimental indices of motor performance. As an index of fine motor function, for example, tests of steadiness typically require an individual to exert a constant submaximal force during an isometric contraction of an isolated muscle or group of muscles, which may have limited functional relevance. Although the fluctuations in force during such steady contractions vary with contraction type, contraction intensity, and age, few studies have examined the functional significance of these fluctuations in the force.
Furthermore, steadiness is often measured during tasks that involve few agonist and antagonist muscles, such as abduction/adduction of the index finger, so that there is a more direct association between the activation signal sent from the nervous system and the resulting mechanical output. Even the simplest everyday task, however, rarely involves such isolated actions, which begs the question of whether or not differences in the steadiness of experimental tasks are associated with differences in functional capabilities. The aim of this study was to investigate the associations among measures of strength, steadiness, and fine motor function of hand muscles across the adult life span.
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