"Silva states that because of the custom nature of the work, he's been asked to make casts of Bonds each year. In the first couple of years, he went through the entire process, but due to his workload, he started checking Bonds with precision calipers each subsequent year. "If I made the same brace every year for 12 or more years," Silva said, "it was because there was no size change in Barry's arms."
You read that correctly--the man who not only builds Bonds' brace, but who has taken precision measurements of his arm since 1992, has not seen any increase in the size of Bonds' arm. Point blank, Silva said "there's been no significant change in the size of his arms."
The article is premium content, paid subscription required, but I'll post the link anyway.
Edit: It helps when you, you know, paste the link. Barry Bonds' Brace