According to a new
study by Tufts University physicist Roger Tobin, steroids is the most plausible explanation for the home runs surge in recent years. Below are his calculations:
1) from 1962 to 1997, nobody hit more than 52 homers a season.
2) since 1998, players have topped 60 homers six times, peaking at 73 (Barry Bonds).
3) since 2003, the annual maximum has fallen back to normal levels.
4)this rise and fall coincides with (a) the emergence of steroids and (b) the subsequent imposition of steroid testing.
5) steroids can increase muscle force and bat kinetic energy by 10%, thereby increasing bat speed by 5%, thereby increasing fly-ball speed by 4%, thereby increasing home-run output by 50%.
6) alternative explanations for the home-run surge -smaller ballparks, weaker pitching, more black players - don't coincide.