Massive calfs can help the athlete to have a good balance or the center of gravity as you have mentioned. Plus it is the main source of his speed and agility. He's mental alertness perfectly synchronized the way he moves. So, regardless of Manny's size, height, and reach he'll be able to compete in a high level of fight with any boxers close to his weight division, because he has the heart and the talent. That's what Thurman missed when he said the word "T-rex arm" to Manny, he under estimated the pure talent in boxing.
since this is my first time on hearing it out or i just simply missed out on when Thurman do said such statement.He might be old but cant be easily beaten down even the opponent is way too younger than him.Cant wait to see for his next opponent and lets see if he would decide to retire after he would able to win that match.