ESA Launches EasyMotion-2 Experiment to Test Electrical Muscle Stimulation for Astronauts

For astronauts aboard the International Space Station, surviving microgravity is a part-time job. Without the constant resistance of Earth's gravity, crew members must spend up to two and a half hours every day running on treadmills and lifting weights just to prevent their bones and muscles from wasting away. But as space agencies look toward multi-year missions to Mars, that immense time cost is becoming a critical bottleneck.[1][3]

This week, the European Space Agency (ESA) and the German Space Agency (DLR) launched a potential solution: the EasyMotion-2 experiment. French astronaut Sophie Adenot has begun testing a specialized electro-myostimulation (EMS) suit during her daily workouts aboard the ISS. By delivering mild electrical impulses directly to her muscles while she exercises, the suit forces stronger contractions, theoretically amplifying the benefits of a shorter workout.[1][2][3][5]

The hardware itself, adapted from commercially available fitness technology, was qualified for spaceflight by the German aerospace company OHB System AG. The suit features dry electrodes integrated directly into the fabric, which are controlled via a tablet app to target specific muscle groups like the back, thighs, and shoulders. Adenot wears the suit while jogging on the station's COLBERT treadmill and using its resistance-training machine.[1][2][3][4][5][6]

To measure the suit's effectiveness, researchers from Charité – Universitätsmedizin Berlin are tracking Adenot's muscle tone and stiffness using a handheld digital device called the MyotonPRO. These in-orbit readings will be compared against baseline MRI scans taken before her launch, as well as data from previous astronauts who trained without the electrical assistance.[1][2][3]

The underlying science of neuromuscular electrical stimulation is not new. On Earth, physical therapists have long used targeted electrical pulses to help rehabilitate patients recovering from spinal cord injuries, severe trauma, or prolonged bed rest. However, translating that clinical success into a reliable, space-rated countermeasure requires proving that the artificial stimulus can genuinely replace the mechanical load of gravity.[1][2][3]

An earlier proof-of-concept test, conducted by German astronaut Matthias Maurer in 2022, showed promising initial results. EasyMotion-2 marks the transition from that early technology demonstration to rigorous scientific validation. The research team plans to expand the trial to include at least eight ISS crew members over the coming years to build a robust statistical case.[2][3][5][6]

If successful, the implications for space exploration are profound. A mission to Mars is expected to last roughly two years, with astronauts needing to operate independently upon arrival. Reducing the daily exercise requirement by even an hour would free up massive amounts of crew time, while also shrinking the footprint and weight of the exercise equipment required on future spacecraft.[1][2][3]

The findings will also translate directly back to Earth. The accelerated muscle atrophy astronauts experience in microgravity closely mirrors sarcopenia—the age-related muscle loss that affects millions of older adults. By learning how to efficiently preserve muscle mass in the extreme environment of space, researchers hope to refine EMS therapies for elderly patients and individuals with reduced mobility, offering a practical tool for maintaining functional independence.[1][3]