Zero-Gravity Workouts
Mobile in Space
Researchers at the Institute of Sports Science and Physical Education of the University of Freiburg are testing gym equipment designed to help astronauts stay in shape while in space.
Countdown. Full throttle. The pilots steer the airplane up into the sky, at a 45 degree angle. The gravity inside the plane is twice as strong as on the Earth’s surface. Even just lifting one’s foot off the floor is a chore. Then the rush of acceleration begins to subside. The gravitation diminishes, and the passengers begin to lose contact with the floor. “There is no up or down; it’s similar to being in water, only there isn’t any resistance at all,” says Ramona Ritzmann, doctoral candidate at the Institute of Sports Science and Physical Education of the University of Freiburg. The airplane continues to ascend for a moment and then starts to fall. After two and a half kilometers the turbines spring into life and pull the machine back up. In the blink of an eye, the gravity is as strong as it was during the ascent. The weightlessness lasted a total of 22 seconds. The pilots bring the airplane back into a horizontal position, thus completing the parabola, and then they immediately initiate a new one. They repeat the maneuver up to 30 times, giving scientists the chance to conduct experiments in a zero-gravity environment: to grow crystals, investigate the properties of materials—or, like Ramona Ritzmann, test prototypes of gym equipment designed to keep astronauts in shape during a journey in outer space.
Astronauts Lose Muscle Mass and Bone
The crew of the International Space Station (ISS) is required to exercise three hours a day, for instance with steppers or exercise bicycles. Even so, the astronauts cannot walk without aid after returning to Earth. They lose an average of ten percent of their muscle mass and one percent of their bone substance each month, because the muscles no longer exert enough pressure on the bones.
However, the international space agencies are planning missions to Mars on which astronauts will be in space for three years at a time, says Prof. Dr. Albert Gollhofer, Director of the Institute of Sports Science and Physical Education: “The exercise methods currently in use are not sufficient for such a long journey.”
Interplay between Nerves and Muscles
Gollhofer is head of a Freiburg research team that is developing new approaches for exercise in weightless environments. The scientists are investigating the interplay between nerves and muscles. Every movement starts with a signal from the nervous system. These signals may be sent by the brain in the case of conscious movement, or they may be sent involuntarily by the sensors in the locomotor system. “We want to reach a more precise understanding of the source of movements and use this knowledge to improve exercise methods,” says Ritzmann. The sports scientist measures neuromuscular adjustment mechanisms in test subjects trying out new exercise machines. “This allows us to determine how effectively the exercises activate the nerves and muscles.”
However, the machines are only suitable for use in space if the body reacts to them in a weightless state in the same way as it would under the influence of gravity. The researchers intend use the parabolic flights to provide evidence of this. “The 22 seconds of weightlessness are sufficient to determine whether the muscles are controlled by the nervous system in the same way,” says Ritzmann. She has taken parabolic flights to try out the exercise machines herself: “So far it seems as if the muscles exhibit comparable activities in a state of weightlessness.” The machines simulate gravity. The research team is testing three training methods: whole body vibration, jumping, and balance control. All three are based on the principle of simulating the gravity that is missing in space with the help of the exercise machines. The exercisers lie on their backs, their feet on a rectangular board. The machines are equipped with straps or a vacuum system that places pressure on the shoulders in the direction of the feet corresponding to the strength of gravity. In the case of whole body vibration, the board under the feet is on springs. When it vibrates, it triggers reflexes that activate the muscles. “We want to provide as many stimuli as possible so that the muscles contract and relax again in rapid succession,” explains Gollhofer. This improves the exerciser’s condition and strength, especially in the legs and the upper body.
The complete version of this article is available in the current issue of uni'wissen.
Ramona Ritzmann und Prof. Dr. Albert Gollhofer
Ramona Ritzmann is working toward a doctorate at the Section for Human Movement Studies of the University of Freiburg and at the Institute of Exercise and Movement Science of the University of Potsdam. She studied at the University of Freiburg from 2001 to 2008 and completed the first State Examination in the fields of sports science and mathematics in 2007. One year later she completed her magister degree in the same two fields. She conducts research in the area of biomechanical movement analysis and on the functioning of the nervous system during exercise in a zero-gravity atmosphere.
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Prof. Dr. Albert Gollhofer has served as professor at and director of the Institute of Sports Science and Physical Education since 2000. He studied physical education, performance psychology, and physics at the University of Freiburg, earned his doctorate in 1986, and completed his habilitation in 1993 with a study on exercise variation and motor coordination. He then accepted a post as professor for sports science with an emphasis on applied biomechanics at the University of Stuttgart. From 2005 to 2009 he also served as president of the sports science organization European College of Sport Science. His research interests include neuromuscular adaptation mechanisms, motor control, and biomechanics.
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Ramona Ritzmann explains the Zero-Gravity Workouts
