Trim it, box the athlete, and their movement becomes an animation you can line up next to others.
Videos never leave your device.
If you have FFmpeg installed, this command makes a version that works here. Then close this and drop the new file. (Add -ss 1:00 -t 10 before -i to keep just 10 seconds from 1:00.)
Add its animations to this board, or replace what's here?