Virginia Tech's football helmets are outfitted with six sensors (the brown objects) that record data. There is also a small antenna that transmits information from the sensors to the sideline controller unit. The sensors are small accelerometers -- similar to devices that trigger an automobile air bag. Courtesy of Dr. Gunnar Brolinson of Virginia Tech hide caption

itoggle caption Courtesy of Dr. Gunnar Brolinson of Virginia Tech

Reggie Bush was all smiles when he was awarded the 2005 Heisman Trophy on Dec. 10, 2005. He called the decision to give the trophy back "heartbreaking." Stephen Chernin/Getty Images hide caption

itoggle caption Stephen Chernin/Getty Images

Katherine Hamilton during a 1981 hurdles race when she was a sophomore at Berkeley. Later that year, Hamilton quit the team and walked away from her sport, largely because of the prevalence of performance-enhancing drugs at the top levels of track and field. Courtesy of Martha Edwards hide caption

itoggle caption Courtesy of Martha Edwards

LeBron James announces his decision during a primetime special hosted by ESPN's Jim Gray on Thursday night at the Boys & Girls Club of America in Greenwich, Conn. Larry Busacca/Getty Images hide caption

itoggle caption Larry Busacca/Getty Images