Corrected entry: Juggernaut's power is the ability to gain great strength but only by building momentum. This was proved when the loss of momentum, by locking his arms and legs down in the mobile prison, is how they were able to contain him. However, when Kitty Pryde sinks him in the floor, he bursts out effortlessly, despite having his arms and legs fully pinned down in concrete and unable to gain momentum.
Spaceboy_007
16th Jun 2006
Correction: Even though Juggernaut is not a mutant in the comic that is not how his power works. Juggernaut has uncharted superhuman strength like the Hulk and could have easily broken through the floor like he did. When he was in the back of the truck the point they were trying to get across was that he is so strong that nothing can stop him short of fully restraining him as so he can not move or even wriggle.
Spaceboy_007