Juan has competed in four paralympics starting with his home games in Spain in 1992. He competed in the pentathlon and 100m before winning a silver in the long jump and gold in the triple jump. The following games in 1996 he defended his triple jump gold medal but could only manage bronze in the long jump. 2000 saw him fail to medal in either of the jumps but he was part of the bronze medal winning 4 × 100 m relay team for Spain. He returned for a fourth games in 1996 where he competed in the long and triple jump but was unable to add any further medals.