The impact of rhythm is huge. The fingertrace activity can teach rhythm when a grammar of action, what we call Action Words , provides a rhythmic template for the movements. Considerable evidence points to the need for gross-motor activity at any level. Research shows that gross patterns are not muscle group specific. They share information readily.
Fine patterns are specific.
We need to provide input and practice at both levels no matter what the age of the student. The study indicates that time spent to develop fluent dynamics will have a positive effect on reading fluency also. Because gross-motor patterns share information readily, it makes sense that the gross dynamics are involved. If you are hard pressed to find enough time to teach everything, the research indicates that time invested to improve handwriting patterns could pay big dividends all across the curriculum. Provide models which allow students to develop understanding.