Back in 2008, they became guests in Super Junior and Shin Donghyup's Explorers of the Human Body.

During the reflex test, Yoochun was the person with the fastest reflex after getting 1.75 seconds in the sliding part where they learn their reflex speed, while Yunho got a 1.83, but it was revealed that that show was the only thing that showed Yoochun had a faster reflex than Yunho, when truth be told, Yunho is told to have the fastest reflex in the group, not Yoochun. 

credit: random

Oh really?? O_O