Robert Martin (born January 6, 1973), better known by his nickname "50", is a streetball player whose fame rose during his years on the AND1 Mixtape Tour. He is 6'8" tall and weighs 210 lbs. He was given the name "50" because people said he has a 50-inch vertical jump.

Martin, born and raised in Atlanta, Georgia, graduated from Tri-Cities High School in 1991. He attended Middle Georgia College from 1991 to 1993 before transferring to High Point College (now High Point University). Martin is also the cousin of NBA star Kenyon Martin of the Denver Nuggets.

In 1995 he joined the Atlanta Trojans of the USBL. From 1995 to 1998 he played in Europe, then in 1998 he played for the Rochester Skeeters of the IBA. In 2001, Martin was offered on a spot on the AND1 Tour.