Sensory-motor integration and motor learning onboard the ISS

Present investigation aims at deepening the motor behaviour of astronauts, during prolonged weightlessness exposure, by analyzing kinematic and dynamic components of the motor strategies. The employed experimental set-up on the International Space Station consists of the purpose-made optoelectronic system ELITE-S2. Two astronauts were involved, performing sessions pre-flight, in-flight and post-flight. The required motor task was a whole body pointing movement protocol. In this paper, the preliminary results of the first astronaut are reported. A new motor strategy in 0g is developed, with a different management of kinematic variables: longer movement duration and greater curved index trajectory, a different coupling of knee angle in the angular coordination, a different displacement of center of mass. The Principal Component Analysis was applied to quantify the intersegmental coordination: the second component augments its role in 0g coordination, representing the different strategy at lower limbs. The inverse dynamic on a 7 segment biomechanical model was employed to quantify forces and torques at joints: it is supposed that the minimization of the torque exchange at the interface point assumes a key role in the movement planning. Future work would compare the data of the two astronauts, hoping in a further increase of the number of astronauts participating in the project.