I’m just going to “spit-ball” with laundry list of ideas and potential connections to science.
1) Bobsleigh design/mechanics as it relates to aerodynamics, friction, and weight distribution.
2) Evolutionary advantages/disadvantages when it comes to swimming. With swimming, you could also talk about the “super suits” and why they were so effective a decreasing times.
3) Energy return in shoes. Hot topic in athletics at moment. You could also look into energy return in different surfaces (grass, sand, mud, asphalt, concrete, cobblestone)
4) The breathing techniques behind free diving.
5) There’s quite a bit you could go with head injuries in various sports (football, American football, rugby, cycling, bobsleigh, skateboarding, etc.)
6) I believe there’s data that states female athletes are suffering joint injuries at a higher rate than men (at least in football), maybe you could look into the scientific theories about that. It’s a bit of a research hot spot in the U.S. at the moment.
7) Wheel hardness in skateboarding and in-line skating. You could look into the chemicals used and how it affects performance in various environments/disciplines.
8) There was that guy who went skydiving without a parachute a few years back (landed in a large net), surely there’s something about physics there.
9) tidal forces and how they impact surfing. Tidal bore surfing might be an interesting case study.
10) The science behind a lot of the para sports is probably interesting (sit-skis, racing wheelchairs, tandem bikes).
11) You could do a case study on athletics with unique biological advantages like Eero Mäntyranta. Link: https://www.scientificamerican.com/article/magic-blood-and-carbon-fiber-legs-at-the-brave-new-olympics/
ESPN had/has a nice series of short videos on sport science. I’m not sure if this playlist is available outside the US (I’m also pretty sure it’s not complete), but I’m sure you could clips on YouTube. Link:
Hopefully you find some of that helpful @ManuCHIL