From Washington Post in 2008

Some statistics on cheerleading injuries:

• 93: Catastrophic incidents between 1982 and 2007 (high school, 67; college, 26)

• 22,900: Number of children who went to emergency rooms with cheerleading injuries in 2002 — more than twice as many as in 1990

• 2.68: Catastrophic injuries for every 100,000 female high school cheerleaders

Catastrophic = leading to death or serious or lasting injury.

Head, neck and back injuries from falls and the occasional internal organ injury from being kicked.

I can't watch it. It is a freaking circus act without nets or supporting cables.