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Physical Demand but Not Dexterity Is Associated with Motor Flexibility during Rapid Reaching in Healthy Young Adults.

Greve C, Hortobàgyi T, Bongers RM - PLoS ONE (2015)

Bottom Line: Here we examine how dexterity demand and physical demand affect flexibility in joint coordination and end-effector kinematics when healthy young adults perform an upper extremity reaching task.Our results demonstrate a proportional increase in stabilizing and de-stabilizing variability without a change in the ratio of the two variability components as physical demands increase.Our findings have practical implications for improving the effectiveness of movement therapy in a wide range of patient groups, maintaining upper extremity function in old adults, and for maximizing athletic performance.

View Article: PubMed Central - PubMed

Affiliation: Center for Human Movement Science, University of Groningen, University Medical Center Groningen, Groningen, The Netherland.

ABSTRACT
Healthy humans are able to place light and heavy objects in small and large target locations with remarkable accuracy. Here we examine how dexterity demand and physical demand affect flexibility in joint coordination and end-effector kinematics when healthy young adults perform an upper extremity reaching task. We manipulated dexterity demand by changing target size and physical demand by increasing external resistance to reaching. Uncontrolled manifold analysis was used to decompose variability in joint coordination patterns into variability stabilizing the end-effector and variability de-stabilizing the end-effector during reaching. Our results demonstrate a proportional increase in stabilizing and de-stabilizing variability without a change in the ratio of the two variability components as physical demands increase. We interpret this finding in the context of previous studies showing that sensorimotor noise increases with increasing physical demands. We propose that the larger de-stabilizing variability as a function of physical demand originated from larger sensorimotor noise in the neuromuscular system. The larger stabilizing variability with larger physical demands is a strategy employed by the neuromuscular system to counter the de-stabilizing variability so that performance stability is maintained. Our findings have practical implications for improving the effectiveness of movement therapy in a wide range of patient groups, maintaining upper extremity function in old adults, and for maximizing athletic performance.

No MeSH data available.


Related in: MedlinePlus

Effects of physical demand on end-effector accuracy expressed as standard deviation error in mm.* p =. 05. Vertical bars denote standard error of the mean.
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pone.0127017.g009: Effects of physical demand on end-effector accuracy expressed as standard deviation error in mm.* p =. 05. Vertical bars denote standard error of the mean.

Mentions: Fig 9 illustrates the significant main effect of the physical demand on end-effector accuracy. Pairwise comparisons showed that after Bonferroni correction the standard deviation of the tangential end-effector position was only significantly higher during the 2 kg condition compared to the 0 kg physical demand condition (p =. 019). Comparing the 0 kg condition with the 0.5, 1 kg and 1.5 kg condition did not show any significant difference.


Physical Demand but Not Dexterity Is Associated with Motor Flexibility during Rapid Reaching in Healthy Young Adults.

Greve C, Hortobàgyi T, Bongers RM - PLoS ONE (2015)

Effects of physical demand on end-effector accuracy expressed as standard deviation error in mm.* p =. 05. Vertical bars denote standard error of the mean.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4430491&req=5

pone.0127017.g009: Effects of physical demand on end-effector accuracy expressed as standard deviation error in mm.* p =. 05. Vertical bars denote standard error of the mean.
Mentions: Fig 9 illustrates the significant main effect of the physical demand on end-effector accuracy. Pairwise comparisons showed that after Bonferroni correction the standard deviation of the tangential end-effector position was only significantly higher during the 2 kg condition compared to the 0 kg physical demand condition (p =. 019). Comparing the 0 kg condition with the 0.5, 1 kg and 1.5 kg condition did not show any significant difference.

Bottom Line: Here we examine how dexterity demand and physical demand affect flexibility in joint coordination and end-effector kinematics when healthy young adults perform an upper extremity reaching task.Our results demonstrate a proportional increase in stabilizing and de-stabilizing variability without a change in the ratio of the two variability components as physical demands increase.Our findings have practical implications for improving the effectiveness of movement therapy in a wide range of patient groups, maintaining upper extremity function in old adults, and for maximizing athletic performance.

View Article: PubMed Central - PubMed

Affiliation: Center for Human Movement Science, University of Groningen, University Medical Center Groningen, Groningen, The Netherland.

ABSTRACT
Healthy humans are able to place light and heavy objects in small and large target locations with remarkable accuracy. Here we examine how dexterity demand and physical demand affect flexibility in joint coordination and end-effector kinematics when healthy young adults perform an upper extremity reaching task. We manipulated dexterity demand by changing target size and physical demand by increasing external resistance to reaching. Uncontrolled manifold analysis was used to decompose variability in joint coordination patterns into variability stabilizing the end-effector and variability de-stabilizing the end-effector during reaching. Our results demonstrate a proportional increase in stabilizing and de-stabilizing variability without a change in the ratio of the two variability components as physical demands increase. We interpret this finding in the context of previous studies showing that sensorimotor noise increases with increasing physical demands. We propose that the larger de-stabilizing variability as a function of physical demand originated from larger sensorimotor noise in the neuromuscular system. The larger stabilizing variability with larger physical demands is a strategy employed by the neuromuscular system to counter the de-stabilizing variability so that performance stability is maintained. Our findings have practical implications for improving the effectiveness of movement therapy in a wide range of patient groups, maintaining upper extremity function in old adults, and for maximizing athletic performance.

No MeSH data available.


Related in: MedlinePlus