Prizefighting, in one form or another (usually melodrama), was the most prevalent theme of sports movies during the decade:

1930 — Hold Everything: Comedian turns prizefighter; features French heavyweight champion Georges Carpehtier

193.1 — The Champ: Washed-up boxer Wallace Beery and his adoring son

The Iron Man: From the W. R. Burnett novel; gold digger Jean Harlow eggs on prizefighter husband Lew Ayres

1932 — The Crowd Roars: Racetrack driver dissuades younger brother from taking up the sport

Horse Feathers: Crooked college football, with the Marx Brothers on the gridiron

1934 — Death on the Diamond

1935 — Alibi Ike: From the Ring Lardner story; travails of a middling pitcher

1936 — Cain and Mabel: Prizefighter, falls in love with showgirl

1937— The Kid Comes Back: Tenderfoot turns prizefighter with the help of a former champ; features light heavyweight champ Maxey Rosenbloom

Kid Galahad: Trainer does too...