It has been reported that children with coordination difficulties produce excessive levels of EMG activity compared to their typically-developing peers . Prolonged muscular co-contraction around the ankle and knee ,
and prolonged erector spinae activity have also been described. However, when
trunk muscle timing is considered with respect to the limb muscle responsible for shoulder movement,
children with DCD demonstrate deficient anticipatory trunk muscle activity in the form of longer
onset latencies . Interestingly, Johnston and colleagues (2002) also found that
the delayed trunk muscle activity was accompanied by earlier activation of certain shoulder girdle
muscles, which have been reported elsewhere to produce excessive EMG activity (Wilson & Trombly,
1984). Thus, it appears that neuromuscular timing (i.e., its association with APAs or RPAs) is pertinent
to the interpretation of amplitude data as well as to the descriptions of neuromuscular activation.