USMC training emphasized that most hand to hand combat ends in grappling and body weight definitely plays a factor. Distinguish from close combat (typically just out arms reach), which typically involves bayonets, buttstocks, and knives, etc and armed CQB with short barreled rifles and submachineguns... Skill and training can offset, but nothing beats a good pistol or shotgun at close quarters.That is pure myth...and a dangerous one to cling to, especially, for example, in time of war, old sport.