Adrenaline Skills Question

Some skills (like Rush, Battle Rage, and Defy Pain) last over a certain time but require adrenaline. Is it possible to re-use them before their time is up?

For example, if I activate Battle Rage and get the required 4Adrenaline again, can I use it again to reset the timer? Or am I not allowed to use the skill while it is currently in effect?

In all cases, the timer will simply be reset.

The catch with Battle Rage though, is when you re-cast it and reset it's timer; it technically "ends"; so you still gain double adrenaline but you lose all adrenaline at that point.