speed
She was ten metres behind at the start of the final lap, but a burst of speed down the home stretch saw her take gold.
Sharks move at a steady pace but are capable of a burst of speed when making an attack.
Then she put her foot down and a burst of speed threw me back in my seat.

SMART Vocabulary: related words and phrases

Speed of motion
at full/half throttleidiom
briskness
celerity
clip
clock
cruising speed
ground speed
hypersonic
hypervelocity
instantaneous velocity
light speed
linear velocity
momentum
pace
speed of sound
speediness
supersonically
swiftness
throttle
velocity