A well know negative a effect of weightlessness, such as an astronaut staying on the International Space Station (ISS), is Musculoskeletal Atrophy. Without the presence of gravity the body of an astronaut does not experience the daily load that it would on Earth. Henceforth, muscles do not receive an adequate amount of stimuli during space travel. Much research has been done to try to combat the process of muscular atrophy within these brave individuals, and while it is rather difficult to test with such a low population to test from, it seems that headway has and is still being made.
This article examines one astronaut that is staying on the ISS. The astronaut wears a Hybrid Test System (HTS) that has been approved by Nasa. The idea of the HTS is to increase the stimuli to one arm and slow the process of atrophy. The HTS is a device that stimulates both the protagonist and antagonist muscles in the astronauts non dominant arm. The dominant arm served as the control. The triceps are stimulated with 21 Volts while the biceps and stimulated with 15.5 Volts. While being stimulated the astronaut performed 10 sets of 10 double arm curls with a 2 second flexion. This was done 3 times a week for 4 weeks roughly seven weeks before the astronaut’s return trip. Several measurements were taken pre, in, and post flight.
Significant differences were observed in several areas: circumference of the upper arm was smaller in the control; total work required, in Joules, increased in the control faster than the trial; and torque, in nm, decreased at a more accelerated rate in the control.
Shiba N, Yoshimitsu K, Ohshima H, et al. Electrically stimulated antagonist muscle contraction increased muscle mass and bone mineral density of one astronaut – Initial verification on the International Space Station. Plos ONE [serial online]. August 21, 2015;10(8)Available from: Scopus®, Ipswich, MA. Accessed February 23, 2016.
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