If NASA ever sends astronauts to Mars, Southwestern University kinesiology professor Scott McLean can say he had a small part in keeping them healthy.
That’s because McLean contributed to a research project NASA did to help determine how astronauts can best exercise in a zero gravity environment.
According to McLean, NASA estimates it will take somewhere between 9 to 12 months for a spacecraft to get to Mars. Both the cardiovascular and skeletal systems can undergo drastic changes over such a long period of time in a zero-gravity environment. While there are drugs that can be taken to counteract changes such as the loss of bone density, they all have side effects.
“If they could, they would prefer to use exercise to prevent the loss of bone mass,” McLean said.
Researchers at NASA’s Johnson Space Center in Houston have been using the international space station to investigate a variety of ways for astronauts to exercise in space, and one of the most promising of these is a small treadmill. But running on a treadmill in space is much different than running on Earth. Astronauts have to wear bungie cords to recreate the effect of gravity. However, bungie cords don’t provide a constant resistance like gravity. Researchers need to figure out how much resistance is enough to stimulate the desired physiological responses while allowing the astronauts to run normally – a factor that can only be determined by analyzing video of astronauts running with varying levels of resistance.
“Their goal is to have the astronauts run as close as possible to how they run on Earth,” McLean said. “If what they prescribe changes the way they run, then other problems may arise.”
McLean said the small area that is available for a treadmill in the space station made it difficult to film astronauts while they were running on it, and therefore to conduct research.
“Their challenge was to figure out how they could use their existing camera to do a full-blown motion analysis of someone running on the space station,” McLean said.
As it turned out, a method that McLean had used to film swimmers underwater for his research could be applied to the situation on the space station. “When you film in a pool you are also restricted by the dimensions of the pool. So, you often have to either angle the camera or use a wide angle lens (which creates distortion) to capture the full movement,” McLean said. To compensate for this, McLean uses a calibration method known as the two-dimensional direct linear transformation, or 2-D DLT.
John DeWitt, a former graduate school classmate of McLean’s who now works as the biomechanist in the exercise physiology lab at Johnson Space Center, asked him if he could help them develop a 2-D DLT system to conduct research on the space station.
McLean worked with DeWitt to come up with a protocol for implementing a 2-D DLT calibration using existing hardware on the space station. NASA began testing the system in 2004-2005 and recently completed a full-scale study on the space station using this methodology.
“They have learned quite a bit from this research,” McLean said. “I am proud to have played a small, but important part in it.”
In the kinesiology classes he teaches at Southwestern, McLean said he talks about this research project a lot because it is a great example of how students can put what they are learning in the classroom to use.
“Students often wonder how they are going to use what they are learning,” McLean said. “There is no better example than this. We took a problem that had unbelievable constraints and were able to get usable data out of it. I think that’s a huge success.”
McLean also takes his students to Houston so they can see the lab where NASA researchers study how astronauts can perform exercise in a zero gravity environment.
2013 graduate Sarah Nonaka, who is now in the doctor of physical therapy program at Texas State University, said she is applying what she learned on her visit to NASA to her planned career.
“I need to get patients out of bed and moving as soon as possible after injury to prevent the same type of bone loss seen in astronauts,” she said.