He will be competing at the Junior Olympic Nationals in Portland , Ore. , on Friday .
Jack Riker , 12 , of Rapid City practices for the Junior Olympic Nationals at the Rapid City Gymnastics Academy .
Jack Riker will be competing at the Junior Olympic Nationals in Portland , Ore. , on Friday .
Jack Riker , 12 , of Rapid City practices for the Junior Olympic Nationals at the Rapid City Gymnastics Academy .