Why do people say ROY JONES has a glass chin?

"Rjj put on all that muscles to be able to fight Ruiz and then after that dropped down to light heavy was his biggest mistake. Cutting all the weight took his reflexes, chin and soul away. He was never the same after that. It’s sad"

but that was it. jones almost NEVER took a REAL hard clean shot DUE to his amazing speed and reflexes. his chin never really was tested. as you said, once he began to slow down just a little and got tagged, that was it. almost like morrison's chin was never the same after running into ray mercer.

 

Being KOed back to back tends to diminish your punch resistance.

 

Holy ****!! Are you serious??

While it might be questioned whether Jones had a china chin in his prime - although it's probable that his exceptional athleticism compensated for the fragile mandible he was likely always sporting - it CANNOT be argued that after his shaky chin was shattered by Tarver that his chin was pure, unadulterated CHINA!!!

 

I said "Where was Roy Jones back when Bill Gates was makin all them computers?"

 

When Roy was younger he was such a physical freak he avoided a lot of shots, rolled with them and used his athleticism to just deflect, block or avoid them altogether. After he moved up to heavy and came down and lost so much muscle weight in a dramatic fashion it made his legs start to go, made him less elusive and more of a stationary target. His greatest gifts were his speed, athleticism and awkwardness. He did not use text book techniques. Roy might never have had the greatest chin but we wouldn’t knows because he was so elusive. After he came back down he really got old over night and people were able to start to catch him. It’s like the young fast rabbit who can avoid the Fox, but the day they get a little older the Fox can start to catch him

 

This.
Same in MMA. Once you get chocked out, you will go out sooner the next time.