Space crew conducts shocking test

Alpha crew: Carl Walz (left) Daniel Bursch (center) and Yuri Onufrienko

By Richard Stenger
CNN Sci-Tech

(CNN) -- Resuming their scientific work after the holidays, the international space station residents took part in an experiment that delivered quite an electric shock.

The test, one of many planned this week, will help measure the effects of space flight on the spinal cord, according to NASA scientists.

The electrical pulse was delivered to the back of the knee on test crewmembers. Instruments recorded the resulting contraction of the calf muscle.

The response, known as the Hoffmann reflex, resembles the leg twitch that takes place when a doctor taps a patient's knee with a rubber hammer. The greater the jerk, the greater the spinal cord excitability.

The human body undergoes numerous physiological changes in the weightlessness of space, affecting the bones, the muscles and the internal equilibrium mechanism, for example.

By studying the Hoffman reflex on Alpha residents, Canadian Space Agency researchers hope to find out more information about changes to the human neurological system during long-duration space flights.

Understanding how the human body changes in space, and figuring ways to counteract those that post health risks, will play a crucial role in planning human expeditions to Mars, NASA researchers said. The shock test could help scientists determine methods to make exercise more effective on long space flights.

The Alpha guinea pigs, astronauts Daniel Bursch and Carl Walz, have little to worry about in the short run. The electrical shock was comparable to what one receives from a jolt of static electricity.

Along with cosmonaut skipper Yuri Onufrienko, they took up residence in the orbiting outpost in December. Other experiments in the works involve everything from culturing cancers cells to growing protein crystals.