I didn't know they changed this rule. But they did. If this is pertaining to the 6th grade game between BA and Jenks that was definitely tripping. But here's the exact rule and the penalty enforcement.
TRIPPING
RULES 2-45, 9-4-3o (NEW),
9-4-3o PENALTY (NEW)
www.nfhs.orgThe foul for tripping has been
expanded to include the runner.
It is now illegal to trip any
opponent. Tripping is the
intentional use of the lower leg
or foot to obstruct an opponent
below the knee. The penalty is
15 yards.