Universal Medical Systems has revealed that they discovered some anomalies while studying baseballs used in 1998. Computerised imaging found that the balls had a larger than normal rubberised core.
The year was made famous in baseball by the home run race between McGwire and Sosa and infamous because of a drug scandal which is yet to be resolved. At the end of the season McGwire had 70 home runs and Sosa had 66.
According to university experts the larger core could well have increased the number of home runs hit. Physics suggest that that ball speed and distance off the bat may have been increased. The league and the manufacturer dismiss the claims.