Track size and turns
An indoor track is most commonly 200 meters around, exactly half of an outdoor 400, which means a single lap covers two turns instead of one gentle bend per straightaway. Those turns are frequently banked to help sprinters and distance runners alike hold speed without losing their footing. Outdoor's 400-meter oval has a much gentler curve, so runners lose less speed through it and can carry more of their top-end pace onto the straight. The tighter, more frequent turns indoors reward agility and turn technique in a way outdoor racing simply does not test as often.

