According to multiple biographies of Burt Lancaster, Barbara Loden's scene with Lancaster was reshot with Janice Rule as Loden's performance had overpowered him in the scene. Using Rule, whose performance was less powerful than that of Loden, restored balance to the scene.
Burt Lancaster did numerous push-ups and sit-ups every morning before each shoot to stay lean and solid. He gained 20 lb. of muscle by doing weights, running, karate and aerobics.
Although the critical response at the time was mixed, critics were unanimous in their praise of Burt Lancaster's physique, especially considering he was 52 at the time of filming.