Speed up or slow down parts of clip?

Is this possible?

All of you might have seen video clips running in a specified frame rate and suddenly when something cool happens (a good face punch if a fight for example) suddenly it slows down or speeds up for a certain amount of time and then it's back to normal.

Can I achieve this with kdenlive?

An example video using this technique a lot:
https://www.youtube.com/watch?v=kh29_SERH0Y [2]

Look at 2:50-2:55. The snowboarder comes at a certain speed and when he does the flip the clip slows down and after a couple of seconds is back to normal.