For those unfamiliar, muscle atrophy is when we do not regularly use or exercise our muscles, leading to them weakening and deterioating. This is especially prevalent in astronauts as maintaining muscle mass while in space has proven to be an issue, where astronauts typically require physiotherapy when they get back to Earth after their missions in space.
Clearly this is a problem, especially if there are plans for extended space missions, but this is something that NASA is working on. The agency is testing out implants that can deliver medication to the wearer that is designed to help slow down muscle deterioation while up in space. This is currently being tested on mice on the International Space Station, which unfortunately means that the medication is years away from being ready and/or approved for human use.
There are also benefits to this medication and its application, where it can also be used not just on astronauts, but patients back on Earth who might be experiencing similar problems as well, either due to disabilities, being in a coma, and so on. The fact that it is worn and can deliver the medication remotely means that those who are in remote parts of the world can benefit from it as well, as doctors can adjust the dosage without having to be there.