How to Maintain Bone Density in Space

Astronauts lose an average of about one to two percent of their bone mineral density for every month that they're in space. Weight bearing exercise on earth, so running, jogging, doing weights, all those sorts of things is really important because it's working on your muscles and bones. But in space, you can't really do weight bearing exercise because there is no gravity to pull down on your whole body. So how are we going to resolve this? I think a lot of scientists at NASA and the European Space Agency are probably going to be looking at this.