This answer by @NReilingh inspired me to trawl the web looking at Sousa music. Feeling that the clarity of orchestration contributes a significant amount to this music, I was pleased to find this ...
Wikipedia states: French Horns tend to always carry the rhythmic backup of a march. For example, in cut-time marches, they are typically assigned upbeats (the + of 1 and 2) to provide the "pah" ...
In many marches, such as the following, the last note of the melody is repeated emphatically (or repeated an octave above). Often using sforzando, marcato, or fortissimo possibile. Here are a few ...