EnduranceMeter

From The EQMac Wiki

Endurance is represented by the yellow bar in the player window. It is considered to be the least important meter and is ignored by most players.

Endurance is depleted by jumping (it takes 10% each jump). Unlike in other MMORPGs, jumping actually makes your character move faster for the duration of the jump, so this is useful for escaping enemies.

Endurance is also depleted every time you swing a weapon in melee combat, and every time you get hit.

[edit] Penalty

If you endurance is completely depleted, you will be unable to jump and less likely to hit your target.