Although some animals run faster than us, all humans want to run fast! Even if this is not your "specialty," you can train your running speed. It might come in handy! Moreover, there are many games that involve running (e.g. hit and run, cops and robbers, etc.).

Ask your partner (dad, mom, or friend) to run fast, and try to
follow behind them. Then swap positions: now you are running
in front. Who runs faster?

Set up a race: on a flat space, set a distance between 50 and
80 meters (more or less 50/80 wide strides). Mark a starting
and finishing line. Who can run faster?

If you are with more friends you can make a "relay" game. Two teams compete to see who runs faster, over the same distance as in situation 2.
Which team is faster? You can also change the distances, the type of of space, and the number of competitors in the teams.