The artificial gravity lab

EMS = electro muscular stimulation? No, not 100%. Astronauts have very good resistance training onboard the ISS at this point. Some of them come back to earth stronger than they left. However, it turns out that your body also needs skeletal loading in order to produce strong bones. That kind of loading comes from having large forces distributed through the entire body. NASA tried a variety of shortcuts around resistance training, but none of them were satisfactory. A spinning drum is probably the best method short of artificial gravity, but it has a couple problems. A rotating reference frame creates some pretty non-intuitive effects ( [this video] ). Research is ongoing about just how fast a human can be spun for a long duration, although data is hard to come by. We also don't know how low of a gravity a human can stay healthy in without intervention like serious exercise. If it turns out that you need 1G, that involves a much larger spinning drum than a G/3 (Mars) or G/6 (Moon) environment. The problem is that we really have no way to simulate those environments for a human.