away from when I played in the 80's and early 90's. My boys today play line and what was holding or not aggressive enough line drive in my day is now the preferred method. Re-directional blocking or shield blocking/zone type blocking allowing the RB to pick his hole instead of traditional drive blocking that required a much more physical and head to head type blocking style is not what we are seeing on the HS level. I notice a lot of this in the NFL as well as you see very few O linemen leaving the game due to concussion while RB's, WR's, and defensive backs leave by far more often with head injuries than the interior line. D Line still takes hits and RB's lower their pads into them, but for me the safest position on the field for head injuries outside of kickers and punters is the O line. I don't recall ever getting my bell run while playing O-Line but when in HS playing TE and DE there were multiple times I was concussed or had my bell rung.