Objects are resistant to changes in velocity.
Inertia is a concept from the science of physics, and it has significant implications to Jiu-Jitsu. In particular:
- It’s hard to get something moving if it’s not already in motion.
- It’s hard to slow something down if it’s already in motion.
If you’ve ever struggled to create kuzushi against a larger opponent, it’s because of inertia.
Similarly, if you’ve ever felt like you have no control over your own movement because your opponent is achieving non-stop kuzushi against you, it’s because of inertia.
If your opponent stops moving, they can develop base. And if they develop base, it’s hard to get them moving again. Against a larger opponent, giving them the opportunity to settle their base can be fight-ending.
So the lesson here is: once you get your opponent off-base, keep them moving so they don’t get it back again.
Inertia is not just applicable to offense, but to defense as well. For example, when on the bottom inside control, being a shifting platform makes it much harder for your opponent to settle their weight on top of you.
If you can, it’s in your best interest to keep your opponent in motion – and off-balance – with constant attacks on their base. Because as inertia teaches us, once they stop moving, it’s hard to get them started again.
Although it’s not based on physics, there’s arguably a social element to inertia as well. Taking the first step in any new journey is terrifying, but once you get moving, it’s a lot easier to maintain the momentum.