Momentum is a combat mode that can be toggled from the Combat Settings interface, or by right-clicking the gear icon in the action bar. When activated, the minimum hit from auto-attacks changes to 24% damage, and the maximum changes to 120% damage. In addition, basic abilities of the relevant combat style are triggered automatically, about once every 20 seconds. Manually triggering any basic or threshold abilities turns off Momentum, but ultimate abilities can be activated without that consequence. Adrenaline is generated fairly slowly (about 80 seconds for 100%). The abilities bar may be minimised to discourage ending the effect by accident, unless the player has no abilities hot-keyed, or if the player wants to deliberately have a way to end the effect through using an ability. However, activating Momentum with adrenaline remaining drains it completely. Momentum effectively increases the damage of auto-attacks by 60%, in addition to the basic abilities and access to ultimates, but it has a considerably worse damage output than either Revolution or manually using abilities.
The basic abilities triggered while under the effects of Momentum are limited. For melee, only Slice, Dismember, Punish and Sever apparently have a chance of being randomly performed. For ranged, Piercing Shot, Binding Shot, Dazing Shot and Fragmentation Shot are randomly performed. For mage, it appears that only Impact, Wrack, Sonic Wave and Combust are randomly used. The damage of random abilities are not boosted. In addition, any basic abilities in melee or ranged that you meet the requirements for can also be randomly performed. For example, dual wielding two swords enables you to use the ability Havoc. It is worth noting that Momentum does not trigger any basic defence abilities such as Resonance or Anticipate even if a shield is equipped, regardless of combat style.
Momentum was added to the game during the beta stage of the Evolution of Combat in a response to players' need for "a less input-intensive way to grind through long Slayer tasks". It was aimed to give the 'old-style' combat a place after the EoC, yet it must be noted that momentum attacks are notably weaker than ability attacks and are strongly not recommended for PVP.