A lot of hard work goes into preparing a 15-minute marching band set. Not only did we have to memorize the music, we had to memorize the movements that went along with the music and carry it out precisely. We did this by using charts to determine where each member needed to be by spray-painting the positions in different numbers and colors. (We tried golf tees one year, and it was an epic failure.) And just like a sports team, each band member had a number assigned to them to find their location on the charts. If you didn't move through the positions at just the right angle and pace, disaster could strike. And by disaster, I mean there was a chance you could get hit in the head by a passing member of the flag corp.
Practice wasn't canceled for weather, either. If it was raining, we headed to the gym and marched in place. There was also the year that we were selected to play for the state football championships. This meant our season lasted several weeks longer than the football team's did. Even though it was freezing outside, we headed out to the field to practice our routine, and we stayed out there until the keys on the trumpets and tubas and slides on the trombones got frozen into place. Even then, we mimed our way through the steps.
A 15-minute set requires more athleticism than "band geeks" are given credit for. As I mentioned above, it takes a lot of precision. Then there's the challenge of keeping a metal instrument (at least for me) parallel to the ground or even higher through the entire set while keeping your posture ram-rod straight while your torso twisted to constantly aim at the press box (judges). Stamina becomes a factor, too, as much of your breath is used to play your instrument while being on the move, sometimes at a high pace. My sophomore year, during our "Little Shop of Horrors" set, I had to hightail about 30 yards in about 16-20 (very fast) beats. I dreaded that part of the show every time.