Mma jabs,cross,hooks make them stronger?

Alright so today I started kickboxing and I'm working on jabs,cross,hooks and such. So I want to know what muscle should I work out to make them stronger

Push ups, pull ups, bench press, etc. Focus on building strength, not mass, as muscle mass is useless in that context.

Also...if the only thing you're practicing is kickboxing, you're not doing MMA, you're practicing kickboxing. Have you seen any MMA fight where it didn't end up in an aikido / jujitsu style standoff? Make sure your grappling skills are top notch, as otherwise, you're out of luck no matter how hard you can throw a right hook.