A bike-like centrifuge that creates artificial gravity mayhelp astronauts combat muscle atrophy in space. Through a study at theUniversity of California, Irvine, the National Space BiomedicalResearch Institute (NSBRI) is exploring the concept of a Space Cyclefor inflight resistance-training exercise.
“Even with onboardexercise, astronauts face the risk of losing muscle mass and functionbecause their muscles are not bearing enough weight, or load,” said Dr.Vincent J. Caiozzo, investigator on NSBRI’s Muscle Alterations andAtrophy Team. “For exploration, it is important to find ways toincrease load-bearing activity so astronauts can maintain strength.”
Caiozzo’steam is researching whether squats executed under artificial gravityconditions greater than or equal to Earth gravity (1g) produce the samekind of muscle responses that occur when a person performs weighttraining on Earth.
With long-term initiatives like theInternational Space Station and the proposed lunar and Mars missions,the rate of muscle loss in some areas might rise to 25 percent unlessmeasures are taken to confront atrophy. The loss of muscle strengthduring an extended mission could pose dramatic problems in the event ofan emergency situation upon landing.
The Space Cycle, ahuman-powered centrifuge under testing in Caiozzo’s lab, generatesvarious levels of artificial gravity ranging from Earth gravity to fivetimes Earth’s gravity. The speed of rotation determines the level ofgravitational force.
Participants ride opposite one another – oneon a bike and one on a platform. As one person pedals, the cycle movesin a circular motion around a centralized pole. The motion generatespressure on the rider, forcing him against the seat in a manner similarto the effect of gravity on Earth. On the platform, the other personperforms squat exercises. Instruments on the device report the separatework rates of the participants.
Caiozzo’s team is determining theSpace Cycle’s effectiveness by comparing the participants’ pre- andpost-study muscle mass and strength, muscle fiber cross-sections frombiopsies, and various cellular and molecular markers of growth.
“Thenovelty of artificial gravity resistance training is that each elementof the body is loaded proportionally. Leg muscles can be made to workagainst high loads without the need for external weights, which isimportant in light of the limited mass and space available onmissions,” said Caiozzo, professor in the Departments of OrthopaedicSurgery, Physiology and Biophysics at UC Irvine.
In collaborationwith Caiozzo, UC Irvine researchers Dr. Joyce Keyak and Dr. Jim Hicksare gathering data from the participants to determine whether the SpaceCycle is also effective in maintaining bone mass and cardiovascularfitness.
“Space Cycle is an artificial gravity exercise gym,”Caiozzo said. “The platform can be fitted with a treadmill, bike or anykind of exercise equipment and provides an environment for exerciseunder normal, Earth-like loading conditions.”
NSBRI,funded by NASA, is a consortium of institutions studying the healthrisks related to long-duration space flight. The Institute’s researchand education projects take place at more than 70 institutions acrossthe United States.
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