Grip force control is dependent on task constraints in children with and without developmental coordination disorder

Excessive grip force (GF) is often found in children with developmental coordination disorder (DCD). However, their GF control may vary when task constraints are imposed upon their motor performance. This study aimed to investigate how their GF control changes in response to task demands, and to examine their tactile sensitivity. Twenty-one children with DCD and 17 controls participated in the study. The instrument used to measure GF was a cylindrical cup equipped with a load cell. The children were asked to hold and transport three cups with varying physical properties as quickly as possible. For tactile function, static and moving two-point discrimination senses were recorded. Data were analyzed using repeated-measures analysis of covariance. Children with DCD displayed slower rate of GF generation, which might be related to their lower sensitivity of two-point dynamic discrimination. Given the slow rate of GF generation and time constraint, the peak GF for children with DCD was lower than that for the control children, but the peak GF of both the groups depended on the time allowed for the performance and the task demand. Both the groups of children cautiously modulated the grip when the cup was filled with water, and graded GF according to the physical property of the cup. We conclude that GF control in children with or without DCD was task dependent. Copyright © 2011 Lippincott Williams & Wilkins.