The Peltzman Effect is named in recognition of Sam Peltzman (econ professor at University of Chicago). The theory states that the safety effect resulting from regulations or safety measures (e.g. wearing helmets) is partially offset by people acting more recklessly due to increased sense of ‘invincibility’.
Hockey and football players often tackle each other at incredible forces. Do you think they would hit just as hard if they were not wearing their safety gear armour? Likely not.
That said, the reduced risk of injury due to better equipment and regulation is likely not fully offset by the Peltzman Effect.