While studying at Delft, Rody Rijnders started competing for the student rowing club Laga. Due to his small stature, he was active as a coxswain, primarily in the coxed pairs and fours. Internationally, Rijnders won two medals, both in the coxed pairs. In 1965 he steered the Dutch boat, manned by Hadriaan van Nes and Lex Winter, to a bronze medal at the European Championships. He gained a second international medal in 1968 by placing second in the Olympic coxed pairs, along with Herman Suselbeek and Van Nes. In national competition, Rijnders’ most important victory was in the coxed fours at the 1968 Varsity, the most important event in student rowing. During the 1967 European Championships, Rijnders caused a commotion when Miss France visited the competition. Along with his team, he thought she was distracting from the sports, and decided to push her into the water. The incident did lead to an eventual athletes-only area at rowing competitions.