Marching instruments are played, as the name suggests, in marching bands, which are known for their special show elements like stick twirling or dance steps. This particular type of brass band has its roots in the USA and is often practised in schools and colleges. The repertoire often consists of popular pop, blues or old jazz titles that are played with classical orchestra instruments. This music style is especially defined by the rhythm section.
Marching has to be played while walking, so it is necessary to have specific mounting systems for the instruments. The drums for example have to be attached to the body in order to wear and play them at the same time.