HERE COMES THE SCIENCE
When you see someone pushing properly into a jump or corner it doesn’t look like they’re doing anything. This is because what’s actually happening here is that they are driving their body weight back into the trail with the same amount of force that is being pushed in towards them. They effectively balance the two opposing forces. Think about it, when you roll around any turn the downward force of gravity and the momentum being carried by you moving forwards is combined. As you change direction the ground is pushing back against you.
In turn you are pushing back into the ground in order to not collapse. The term to describe what’s happening here in its simplest form is Centripetal Force. In scientific terms, the force that you put into your bike is equal to your mass times your speed squared, divided by the radius of the turn. In other words if you weigh more and are going fast on a tighter corner it will feel like you have to push harder than if you’re going slower over a longer corner. In both of these situations though you’re only pushing equal to the amount of force that’s being applied against you.