Yo Penitentiary, calm down.
Jamaa Fanaka's jailhouse grind is the wackiest, sweatiest, sex-in-the-bathroomiest, boxingsploitation film I've ever seen. Everything is excessive, characters performances are wrapped in slapstick, a prisoner bull-charges his opponent during a boxing fight, the prison's oldest inmate spouts proverbs and drops lines like, "I ain't workin' myself up for no pussy of the week contest" while peddling goodbar on the side, another inmate, acts like a dog. There's also a Rocky-esque character arc, but you only see it happen in the last few minutes.
Mostly, Penitentiary is about slippery, sweaty, claustrophobic brawls, and fornicating in slippery, sweaty, claustrophobic bathrooms.
It's sounds like an acquired taste, but I'd recommend this nonsense to everyone.