The University Network

San Francisco State University Graduate Student Studies Female Musculature for Space Travel

A San Francisco State University student analyzed muscle biopsies from a previous study initiated at California State University, Long Beach and discovered unexpected results regarding female musculature. Marsh found that female astronaut musculature can manage a prolonged spaceflight better than male astronauts’ because their muscles might not be as affected during spaceflight.

Kaylie Marsh is a graduate student studying kinesiology at San Francisco State University, and her research may encourage the demand for women in space. “If we’re doing these spaceflights to Mars that last six months, maybe we should be targeting females and encouraging them more to go into space because it might not affect their musculature as much as men,” Marsh said in a statement.

The journey to Mars is a six-month journey. With major advancements in technology, NASA is getting closer and closer to being able to send astronauts to Mars. While journeying to Mars may be a great accomplishment for the U.S., the health and safety of astronauts during this journey are critical concerns.

Marsh’s research was initially aimed at efforts to prevent muscle atrophy in low gravity by developing exercise countermeasures. “Because there is very little gravity in space, astronauts face a significant loss of muscle and bone mass during prolonged spaceflights,” Marsh told The University Network (TUN). “In fact, astronauts can lose about 10 to 15 percent of their muscle mass during six months on board the International Space Station with current exercise countermeasures.”

Even with exercise, a significant amount of muscle mass is still being lost during space travel. The current challenge researchers face is finding new ways to use in-flight exercises to maintain enough muscle to make the trip to Mars. The International Space Station is equipped with various fitness equipment, including a treadmill, stationary bicycle, and a weightlifting simulator to reduce deterioration in muscular and cardiovascular functions, but these exercises have not eliminated muscle loss.

In her research, Marsh used biopsies from a previous study at California State University, Long Beach by a colleague of Professor Jimmy Bagley, assistant professor of kinesiology at SF State. Bagley’s colleague performed the experiment on eight healthy men and eight healthy women. The participants used crutches to get around and wore a shoe with a one-and-a-half inch sole on one foot and left the other leg dangling for ten days. One group performed regular exercises each day with a dangled leg, and the other group dangled their leg without a countermeasure. Muscle biopsies were taken before and after the 10-day period, and Marsh’s analysis revealed that female muscles might be affected less than male muscles.

“I was seeing all these differences with women responding differently than men,” Marsh said in a statement. “At least in my study, some of the women’s muscle fibers were bigger in general than the men’s fibers, suggesting that gender made little difference at the cellular level in our participants. And you would think the opposite, because men are typically stronger than women.”

Marsh’s study was motivated by her interest in molecular changes in muscles. “I was interested generally in molecular changes in muscles,” she told TUN. “That could be from any kind of intervention — if someone is a strength athlete, if they’re inactive or if they’re aging. And for spaceflight, the mechanism that happens when atrophy takes place is probably one of the most perfect mechanisms to study.”

While the loss of muscle mass is a major concern for spaceflight, there are also concerns of bone loss and radiation exposure during spaceflight, which NASA is researching.


To date, 537 astronauts have traveled to space, but only 60 of them have been women. Marsh’s discovery of the difference in molecular changes in muscles between men and women serves as a foundation for future developments in muscle exercises for female astronauts, and hopefully pave the way for more space missions for female astronauts.



Vanessa Sewell is studying Economics and Communications at Boston College. She is from Bronx, NY. Vanessa has worked on topics related to lifestyle, fashion, culture, and education during her time at Boston College. During her free time, she can be found playing piano and guitar or jamming to Spotify.