Official Rules of NFHS-Level Baseball

NFHS 8-4-1g

NFHS 8-4-1g/OBR 5.09a11 If the batter-runner is running outside of the 3-foot running lane on his way to first base and hinders either the fielder throwing to first or the fielder receiving the throw at first, it is interference. [OBR: does not consider whether the runner hindered the thrower, only the fielder receiving the throw. […]