I was watching a NASA documentary recently. They were showing some of their coolest astronauts and engineers, clearly trying to sex up their image, and presumably help retain their always-threatened funding. It was fun to watch.
One astronaut was talking about living on the space shuttle for long periods of time, and described how working in zero gravity for long periods of time causes muscles to atrophy. He said he would exercise for an hour a day to compensate, but that he still ended up quite weak. That’s when they showed him exercising, running on a treadmill, possibly the worst type of exercise to do in zero gravity, and I laughed. Think about it – when there’s no gravity, what’s the point of running? Maybe you’d get a very small cardio benefit, but when you’re barely pushing any weight, you’re barely working. You’re certainly not getting any significant muscle stimulation – it would be about like making a swimming motion in the air with your arms and thinking you’re getting a swimming workout.
Even on earth, treadmills are limited in their effectiveness. You can get a decent cardio workout on one if you work hard, but for example, people who solely train on treadmills and then try to run, say, a 5K find that the treadmill did not fully prepare them for actual running. For one thing, you barely push forward on a treadmill because the machine takes care of that. But people like treadmills because they’re easy to use, and you can watch TV while doing it. (And that’s certainly better than sitting on a couch, to be sure)
To preserve muscle and keep bones strong, you need to apply force, and with no gravity, that’s very difficult, but there are ways you can do it. Using rubber tubing effectively would achieve this, or isometrics – pressing against yourself or immovable objects. And those are just a couple examples. On the show, they were experimenting with huge centrifuges that would simulate gravity for running and so on. But wow, what a typical engineer’s solution – very cool and costing zillions when with a little creativity and advice from the right people, they could do this for next to nothing. No wonder they have cost overruns. But ask an engineer to solve an exercise problem, and I guess that’s what you get.
Maybe the astronauts actually are already doing other types of exercise than jogging on a treadmill, and they just didn’t show it. I hope so, for their sake. Either that, or they need to hire some exercise physiologists.