Boxing is a combat sport in which two people throw punches at each other with gloved hands. Boxing requires strength, speed, endurance and fast reflexes. Also included here under the heading Boxing are mixed martial arts punching and martial art punching such as in karate. Karate punches are straight thrusts and arguably less powerful than a boxer’s follow-through punches. Types of movements in boxing include jabs (punches which retract) and hooks and uppercuts (follow-through punches).
Boxing involves head flexion and extension, cervical flexion, sidebending and rotation, thoracic flexion and extension, lumbar flexion and extension, sidebending and rotation, scapula retraction, protraction, ……
Arm wrestling is a combat sport with two participants. Each participant places the elbow of one bent arm (usually the right) on a table surface and grasps the other participant’s hand. The goal is to pin the opponents forearm and hand onto the table surface with the arm.
Arm wrestling involves thoracic and lumbar sidebending and rotation, shoulder extension, adduction and internal rotation, elbow flexion and pronation, wrist and hand flexion.
In addition to stretching the prime movers you will need to stretch their antagonists and joint stabiliser such as the muscles of scapula retraction and protraction, hip extension and abduction and knee extension.