It is said that in Martial Arts you learn how to use your attackers weight and leverage against him…
Size and strength may not be the difference maker but when you have equally trained athletes with comparable skills size will have a greater influence. Therefore all combat sports Boxing, Judo, Jiu Jitsu, Wrestling and MMA all have evolved into Weight Classes in order to allow for safe competition.
Follow link to read Professor Ricardo Almeida’s article on Size vs Technique in Martial Arts.
He uses an example of an epic Judo match during the 2012 Olympics in London