Pre-programming in overhand throwing of children with Down syndrome: role of the generalized motor program

It is unclear whether slowness and higher reaction time of individuals with Down syndrome (DS) are because of inability to pre-program and using the generalized motor program (GMP) or not. So, the purpose of this study was to examine the consistency of relative timing as a fixed feature of a GMP in overhand throwing with changing the distance to target as a varied feature. Fifteen individuals with DS (age = 13 ± 2 y) and a control group of 12 individuals without intellectual disability (ID; age = 13 ± 2 y) were asked to throw a tennis ball to a fixed target from three distances of 2, 2.75, and 3.25 m, respectively. Instant of occurrence of the following discrete variables was recorded by motion analysis: initiation of elbow extension, maximum shoulder angular velocity, maximum elbow angular velocity, and maximum resultant hand velocity. Results of two-way analysis of variance test did not show any significant difference in any of the relative kinematic variables in distances and groups (p > 0.05). It seems that individuals with DS are able to motor preprogram and they use a GMP to overhand throwing from different distances as well as those without ID. Also, slowness and reaction time are unrelated to pre-programming and GMP as it relates to overhand throwing.