An impulse burst was a brief but intense energy pulse from a vessel's impulse engines which could be used to achieve an extra yield of sublight velocity in emergency situations.

In 2371, B'Elanna Torres released power from the USS Voyager's impulse capacitance cells into its driver coils to create an impulse burst in the hopes of breaking free from a magnetic wake generated by a swarm of space-dwelling lifeforms. (VOY: "Elogium")

In 2373, Commander Chakotay ordered the initiation of a high-intensity impulse burst in an attempt to reach a wormhole which could have provided the crew with a means to return to the Alpha Quadrant. The impulse burst was not enough to allow Voyager to reach the wormhole before it destabilized. (VOY: "False Profits")

In the alternate reality, Hikaru Sulu ordered Pavel Chekov to fire a one-quarter impulse burst for five seconds, in order to maneuver the ship into place above Saturn's rings. (Star Trek)