An orbiting spacecraft or space station continues in orbit because its forward momentum carries it around the planet even as gravity tries to pull it down. So astronauts are literally "falling" toward the Earth when they are in orbit. This "freefall" means that they do not experience the actual acceleration force. Nothing in an orbiting spacecraft experiences effective gravity, so moving around is much easier, and objects have to be secured to prevent them from floating away.

However, objects still have the same mass, so will have the same inertia if moving: an iron weight thrown across the cabin will impact with the same force if it hits something, and a huge satellite in a shuttle launch bay will still require a lot of energy to push from the bay. But the absence of gravity would make exercises such as a one-hand push-up ridiculously easy to do.