RFD - Rate of Force Development
This metric along with contact time is most often used with the repeated style jumps (no pause) just continuous jumping.
Having said that, we find these metrics easily affected by protocol and athlete coordination. With the continuous jumps, coordination plays a big role and often the athletes end up jumping off the spot quite a bit. And they tend to gain momentum through each rep. Also, one poor landing then affects the next jump... So the numbers tend to be quite variable.
We have found that within the literature that there is so much variation on how it is calculated. The results of this seem to be quite variable, hence the suggestion of using Mean Power or Peak Velocity as the key performance indicator.