Green’s Dictionary of Slang

1. (Aus.) married.

1895

Crowe Aus. Sl. Dict. 98: Yoked, married.

2. (US campus, also yoked up) muscular, well-built [? one’s shoulders resemble a SE yoke].

1985		T.R. Houser Central Sl. 60: yoked-up [...] To be muscularly pumped-up.
1989		P. Munro Sl. U. 210: He was so yoked I could see every one of his abdominal muscles.
2000		P. Beatty Tuff 195: These niggers ain’t just fat. Look at the leg muscles. The goddam pecs. These boys is yoked.