Simplify the following text for a Grade 9 native English-speaking person.
Original: Another disabled athlete to appear in the Olympics prior to the Paralympic Games was Liz Hartel , a Danish equestrian athlete who had contracted polio in 1943 and won a silver medal in the dressage event .
Simplified: Another disabled athlete to appear in the Olympics prior to the Paralympic Games was Liz Hartel . She was a Danish equestrian athlete who had contracted polio in 1943 .