An elite gymnast for eight years, she represented the United States at the 1988 Summer Olympics in Seoul, South Korea.

At the 1983 World Artistic Gymnastics Championships in Budapest, she contributed to the U.S. team's seventh-place finish but did not qualify to any individual event finals.

She competed at the 1986 Olympic Festival in Houston and placed fourth in the all-around and on the vault, fifth on floor exercise, and sixth on the uneven bars.

At the Pan American Games, she won gold medals in the team and balance beam competitions and placed third in the all-around.

At the 1988 National Championships, Garrison placed second in the all-around, behind Phoebe Mills, and won the gold medal on beam and 3rd on floor.

At the 1988 Summer Olympic Games in Seoul, Garrison competed on all four events in the team compulsories and optionals, scoring 38.975 in the former and 38.85 in the latter.

(The U.S. women won several medals at the 1984 Summer Olympics in Los Angeles, but those Games were boycotted by the Soviet Union and East Germany.)

The president of the International Gymnastics Federation (FIG) at the time, Yuri Titov, apologized to the Americans after the compulsories.