What does it mean when you have a glowing health bar and how do you use it?

When you have a glowing health bar, it means you should stop blocking or you're going to get guard crushed, and may even be the victim of a critical finisher.

actually i think he meant the other glowing health bar, where its blue, i believe that means your special ability is ready? not sure

"actually i think he meant the other glowing health bar, where its blue, i believe that means your special ability is ready? not sure
"

Thanks anyway guys I figured it out. You just have to be close enough to grab the person and then hit L1 with the default controls.