Rocket League has existed in its current state for more than three years now, and developer Psyonix has stayed mostly hands-off with the minutiae of how everything works. It’s nearly the exact same game that launched in July 2015. That’s why it’s so Capital A1 Wild that players keep finding new mechanics to implement on a semi-regular(ish) basis.
The newest one is being called a “ground reset” by the community, at least for now. Explaining it requires a bit of technical backstory. In Rocket League, you have two jumps every time you leave the ground. The first jump gets you airborne, and then you have approximately 1.5 seconds to use the second jump. If you don’t use it, it’s gone until you land on the ground again.
For the longest time, players have worked on intricate ways to exploit when and how they use their jumps. There are two widely-accepted methods. Falling off the ceiling means that the first jump is never used. That leads to players preserving their jump/dodge for as long as they want, so they can flick into the ball for a surprise shot on goal at any point. Ceiling shots have become a big part of the high-level Rocket League meta in the past year or so.
The other method is more in-line with how the ground reset works. Jumps are restored anytime all four of the car’s wheels touch a surface. Most times it’s used on the ground when landing. But, skilled players can earn flip resets by carefully positioning the vehicle to touch all its wheels on the ball while both are in the air. This gives back both jumps/dodges that, again, usually get used for an unpredictable shot on goal.
Source: Destructoid Rocket League players found a new mechanic three years after launch