Speed, pace (5)
I believe the answer is:
tempo
This clue is a double definition.
'speed' is the first definition.
(I've seen this before)
'pace' is the second definition.
(I know that pace can be written as tempo)
(Other definitions for tempo that I've seen before include "Speed of 3A" , "Cadence" , "Musical beat or rhythm" , "Rhythm, metre" , "Speed at which piece of music is played" .)