Okay kiddo, so do you know what a bike is? Good! So, some people like to ride their bikes on normal roads, but some people like to ride their bikes on really crazy and difficult courses. That's what mountain bike trials is all about!
Instead of just riding a bike from point A to point B, in mountain bike trials, riders have to do special tricks and moves to get through really tricky courses. Like jumping over big rocks or logs, riding on narrow paths without falling off, and balancing on their bike in really hard positions.
It's kind of like a game or a puzzle - the riders have to figure out the best way to get through the course without falling off their bike or messing up. And they get points for doing really cool or difficult tricks or moves.
It takes a lot of practice, skill, and bravery to do mountain bike trials, but it's also a lot of fun and really cool to watch!