Quantitative analysis of neutral body posture in prolonged microgravity.

The experiment was performed during a 6-month space flight and focused on the quantitative three-dimensional description of the Neutral Body Posture (NBP) and of subjects' spine anthropometry in Erect Posture (EP). The NBP joint angles' configuration is described along the long-term microgravity exposure and compared with respect to previous in-flight collected data. Observed spinal length modification during EP in-flight is related to on-ground investigations focused on circadian anthropometrical fluctuations. The flattening of the spinal lumbar lordosis and thoracic kyphosis is also described. Even though only two subjects were studied, this analysis points out the maturity of the opto-electronic technology for the quantitative analysis of posture in microgravity and confirms the need of enriching the anthropometrical database of human postures in weightlessness for the design optimization of permanently inhabited space modules.