The football field at John Carroll Catholic High School in Birmingham, Alabama looks like just about any other in the south-eastern United States.
A bright red athletics track rings around a long rectangle of scuffed green grass, trodden thin over the past ten days, with two American football goal-posts poking up like forks into the golden afternoon sky.
White marquee tents are dotted around the field's perimeter, beneath which rows of tables and chairs hold towels and medical kits and bottles of water.
