26-30 Pullups

Pull-Ups in Space

Here's a problem you never think about on Earth: how do you do a pull-up when nothing weighs anything? In orbit, an astronaut and a wrench and a laptop all drift with the same effortless ease. Grab a bar and pull, and you simply float toward it. Gravity, the very thing a pull-up works against, is essentially missing, which makes the classic version of the exercise impossible. Yet staying strong in space matters more than almost anywhere, and that tension has produced some clever engineering.

The reason astronauts train so seriously is that microgravity removes the constant, gentle load our bodies are built around. On the ground, just standing and moving keeps muscles and bones under a low background of stress. Take that away for weeks or months and the body has far less reason to hold onto its conditioning, so astronauts follow a structured daily exercise routine to keep their strength, cardiovascular fitness, and general capability up. There's a mental payoff too: a hard workout is one of the more reliable ways to break up the routine and stress of living in a sealed can far from home.

Since a normal pull-up won't work, the International Space Station relies on a machine built for the job, the Advanced Resistive Exercise Device, or ARED. Instead of using bodyweight against gravity, the ARED generates resistance with vacuum cylinders that can be dialed up or down, so an astronaut can load a movement to whatever difficulty they need. Foot restraints hold them in place, since without them any hard pull would just send them tumbling backward across the module.

With that setup, astronauts can perform pulling movements that stand in for pull-ups, gripping handles and drawing the body upward through a full range of motion. The device engages the same back, shoulder, and arm muscles the exercise targets on Earth, and it doubles as grip training, which matters enormously for handling tools during a spacewalk. Sensors log force and repetitions so the crew and the teams on the ground can track how each astronaut is holding up.

It isn't frictionless. Astronauts need time to adapt to how movement feels without gravity, the equipment demands regular maintenance, and finding workout time in a schedule packed with experiments is its own challenge. Still, the fact that resistance exercise made the cut on one of the most cramped, expensive outposts humans have ever built says something about how much it's valued. Even in orbit, it seems, you can't skip the workout.