Adrenaline

Certain Warrior skills are fueled by adrenaline rather than Energy. It is gradually built up each time the Warrior hits or is struck in combat, each such blow being added to the characters adrenaline level. Some skills increase the rate of adrenaline build up, while others expend it entirely.

Adrenaline Points
Adrenaline is not actually gained in strikes, but in points. See this table for approximate number of adrenaline points needed for skills.

1Sever Artery and Counter Blow are 4 strike skills, but they actually need about 100 adrenaline points. The "points needed" row increases linear, the "adrenaline strikes" numbers are an irritating simplification.

Gaining adrenaline
You gain 25 adrenaline points for every of your atacks that hits and you gain 1 point of adrenaline for every 1% health lost from your maximum. Note that this includes ranged attacks and excludes health degeneration. Commonly 4 strike skills are charged in about 3 hits time, because you take some damage at the same time.

Skills that boost adrenaline

 * With Berserker Stance you gain 31,25 points every time you hit in melee (instead of 25).
 * With "For Great Justice!" you gain 50 points every time you attack (including ranged attacks).
 * With Battle Rage you gain 50 points every time you attack and 2 points for every 1% health lost from your maximum.
 * With "To the Limit!" you gain 25 points for each foe in the area (max 25...125).
 * With Wary Stance you gain ? points every time you block an attack.
 * With Ferocious Strike you gain ? points if your pet hits.
 * With Balthazar's Spirit you gain +2...5 points every time you take damage.
 * With Dark Fury you gain +25 points if you hit.

Reference
Research done by Ensign and Silmor. Original GW Guru thread.