We investigated
finger strength and the ability to control digit force/torque production in children with
developmental coordination disorder (DCD) using manipulative tasks with different kinetic redundancies (KNR). Age-related changes in
finger strength and
finger force/torque control in typically developing (TD) children were also examined to provide a developmental landscape that allows a comparison with children with DCD. Forty-eight TD children (7-, 9-, and 11- year-olds) and sixteen 9-year-old children with DCD participated in the study. Three isometric tasks with different KNR were tested: constant
index finger pressing force production (KNR=0), constant thumb-index
finger pinching force production (KNR=1), and constant thumb-index
finger torque production (KNR=5). Each subject performed two conditions for each isometric task: maximum voluntary force/torque production and constant force/torque control (40% of maximum force/torque). The results showed that the maximum force/torque production increased and the variability of constant force/torque control decreased with age in all tasks in TD children. Children with DCD showed larger variability than TD children in the constant thumb-index
finger pinching torque production. These results suggest that children with DCD, as compared to TD children, are capable of producing the same level of maximum
finger force, but have poor control in manipulation tasks with a large number of kinetic redundancies.
