What Muscle is mainly used for the Muay Thai Clinch?

when performing the muay thai clinch what muscle should I workout to make it stronger and tougher to get out of.|||I think working your neck and back muscles to allow you to keep from getting pulled down will be the best muscle group to target.|||You use most of them, but if you want to focus on a group, do the core muscles (abs, lower back) you use those alot in Muay thai.|||For the actual clinch part: shoulders, traps, and upper back.