Birchenough's first international competition was the 1921 Women's Olympiad in Monte Carlo, where she formed part of a team representing the Polytechnic, and won the javelin competition. The following year, she was a founder of the Women's Amateur Athletic Association (WAAA) and in 1923 participated at the first WAAA Championships becoming british champion in shot-put. She also held its discus title from 1924 until 1928. In 1924 the participated in the 1924 Women's Olympiad taking the bronze medal in the discus throw. By 1927, she had at some point held the British record in all three of her events. She captained the British team at the 1926 Women's World Games.