Many writings talk about how Elvis exercised constantly. He practiced Racketball. He rode a stationary bike at Graceland. He practiced Karate.
Stomach Exercised
Elvis installed a stomach exercising rack so he could concentrate on exercising his stomach.
In the 70’s he started playing racquetball with the “Memphis Mob.” He started playing at the local Y and at Memphis State. His two favorite things to do was to ... go to the movies and play racquetball. In the summer of 1975, Elvis decided to bring his racquetball hobby closer to home. He began planning to build a racquetball court at Graceland, and construction of the building began in September 1975.
He played racquetball almost daily.

Graceland Racquetball Court
Frank Sinatra
Frank Sinatra played golf and tennis constantly for exercise.
Opera
A famous opera singer practiced yoga 2 hours every day. Other opera singers would say that he was the best singer they had ever heard.
Caruso was a deep diver and long distance swimmer.
All great singers exercised constantly.