The neutral body posture (NBP) is the posture the human body naturally assumes in

microgravity The term micro-g environment (also μg, often referred to by the term microgravity) is more or less synonymous with the terms '' weightlessness'' and ''zero-g'', but emphasising that g-forces are never exactly zero—just very small (on the ...

. Adopting any other posture while floating requires muscular effort. In the 1980s, NASA developed the Man-System Integration Standards (MSIS), a set of guidelines based on

anthropometry Anthropometry () refers to the measurement of the human individual. An early tool of physical anthropology, it has been used for identification, for the purposes of understanding human physical variation, in paleoanthropology and in various atte ...

and

biomechanics Biomechanics is the study of the structure, function and motion of the mechanical aspects of biological systems, at any level from whole organisms to organs, cells and cell organelles, using the methods of mechanics. Biomechanics is a branch ...

, which included a definition of an average typical NBP created from measurements of crew members in the microgravity environment onboard

Skylab Skylab was the first United States space station, launched by NASA, occupied for about 24 weeks between May 1973 and February 1974. It was operated by three separate three-astronaut crews: Skylab 2, Skylab 3, and Skylab 4. Major operation ...

. Still photographs taken on Skylab of crew members showed that in microgravity, the body assumed a distinguishable posture with the arms raised, the shoulder abducted, the knees flexed with noticeable hip flexion, and the foot plantar flexed. STS-57 crew member neutral body postures

STS-57 crew member neutral body postures

Later work by NASA based on research aboard Space Shuttle mission

STS-57 STS-57 was a NASA Space Shuttle-Spacehab mission of that launched 21 June 1993 from Kennedy Space Center, Florida. Crew Spacewalk * '' Low and Wisoff '' – EVA 1 * EVA 1 Start: 25 June 1993 * EVA 1 End: 25 June 1993 * Duration: 5 hours ...

found greater individual variations between crew members' neutral body positions than originally suggested by the earlier Skylab study. In general, three main postures were exhibited by the crew as a whole. These constituted (1) an almost standing posture, (2) a slightly pitched forward posture with an extreme bend at the knees, and (3) an elongated posture with a straight neck. Differences in posture exhibited in this study could be a result of the athletic bearing of the participants or the type of exercise, or both, and the amount of exercise regularly performed. Other differences may also stem from past physical injuries such as bone breaks and knee or shoulder injuries, and from gender differences such as center of gravity. No single crew member exhibited the typical NBP called out in the MSIS standard. The neutral body posture occurs during a state of weightlessness and minimizes the body’s need to support itself against the pull of gravity. This offloads musculoskeletal stress and reduces pressure on the diaphragm and spine. Neutral body posture supports the natural curvature of the spine. A

neutral spine Spinal posture is the position of the spine in the human body. It is debated what the optimal spinal posture is, and whether poor spinal posture causes lower back pain. Neutral spine Looking directly at the front or back of the body, the 33 verteb ...

that is not experiencing mechanical stress will curve inward at the neck (cervical region), outward at the upper back (thoracic region), and inward at the lower back (lumbar region).“Understanding Neutral Spine Position and the Core Muscles”
Team USA. Retrieved 18 December 2020. NASA standards for the neutral body position have informed seat design for commercial vehicle manufacturers. In 2005, engineers and scientists at

Nissan Motor Company , trading as Nissan Motor Corporation and often shortened to Nissan, is a Japanese multinational automobile manufacturer headquartered in Nishi-ku, Yokohama, Japan. The company sells its vehicles under the Nissan, Infiniti, and Datsun bran ...

used NBP research in the development of driver’s seats in their new vehicles.

References

Anthropometry Biomechanics Human positions Posture {{anatomy-stub

See also

References