What are some good ideas for a Gymnastics related Science Fair Project?

[CamSeawind]

I have to do another project this year (I did one last year, GURRR...) because I'm in an honors class and I was going to do a project measuring hte amount of height and distance a gymnast of a certain size gets from certain kind of floor (trampoline, rod, ski, spring, ext...) but hen my dad (scientist) said that I couldn't do it because it involved people (weird right?).

I'm in 9th grade so I needed a harder project I guess...this project would be fun and I guess someone of a younger age could do it, have fun with it

I've ended up trying out different household items as snail repellent/killer for my project if your wondering