Momentum was a combat mode that could 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 changed to 24% weapon damage, and the maximum changed to 120% weapon damage. In addition, random basic abilities of the relevant combat style were triggered automatically, about once every 20 seconds.
Manually triggering any basic or threshold abilities turned off Momentum, but ultimate abilities could be activated without that consequence. Adrenaline was generated fairly slowly (about 80 seconds for 100%). The abilities bar could be minimised to discourage ending the effect by accident, unless the player had no abilities hot-keyed, or if the player wanted to deliberately have a way to end the effect through using an ability. However, activating Momentum with adrenaline remaining drained it completely.
Momentum effectively increased the damage of auto-attacks by 60%, in addition to the random usage of basic abilities and access to ultimates, but it had a considerably worse damage output than either Revolution or manually using abilities. For comparison, Momentum was approximately 23% ability damage per game tick, Legacy Mode combat is around 26%, and many Revolution bars can reach greater than 28% (without threshold or ultimate abilities).
Momentum would randomly trigger the following basic abilities, as long as the level and handedness requirements were met:
The damage of random abilities was not boosted. Momentum did not trigger any basic Defence or Constitution abilities such as Resonance or Anticipate even if a shield was 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 were notably weaker than ability attacks and were strongly not recommended for PvP.
- Momentum used to be an ultimate ability that ran out after 20 minutes, but was changed to a basic ability that lasts indefinitely on 18 March 2013. On 24 February 2014, Momentum was changed into a combat mode, and the ultimate abilities functionality was added.
- Attempting to toggle momentum during a player-owned port random event gives the message "You can't do that while transmogrified into this form."