The Cheerleaders (1973)

Jeannie, a teenage girl attending Amorosa High, joins the school cheerleading squad as a means of finally attaining the success and social independence that was out of reach in the strict household her parents maintain.

The liberated attitude of her new friends becomes all the more evident when they come up with a plan to help the football team win the big game by kidnapping and raping everyone on the opposing team until they're too tired to even take the field.