ESA astronaut Alexander Gerst using the International Space Station’s Advanced Resistive Exercise Device (ARED) to keep fit. Astronauts need to spend up to two hours each day working out to counteract the loss of bone and muscle fibre that comes from living in space.
ARED is similar to a multifunctional weightlifting machine on Earth but, of course, weights are not much use in weightlessness. Instead, pneumatic resistance achieves the same result: exercising the muscles.