Effects of Simulated Microgravity and Hypergravity Conditions on Arm Movements in Normogravity

Abstract

The human sensorimotor control has evolved in the Earth’s environment where all movement is influenced by the gravitational force. Changes in this environmental force can severely impact the performance of arm movements which can be detrimental in completing certain tasks such as piloting or controlling complex vehicles. For this reason, subjects that are required to perform such tasks undergo extensive training procedures in order to minimize the chances of failure. We investigated whether local gravity simulation of altered gravitational conditions on the arm would lead to changes in kinematic parameters comparable to the full-body experience of microgravity and hypergravity onboard a parabolic flight. To see if this would be a feasible approach for on-ground training of arm reaching movements in altered gravity conditions we developed a robotic device that was able to apply forces at the wrist in order to simulate micro- or hypergravity conditions for the arm while subjects performed pointing movements on a touch screen. We analyzed and compared the results of several kinematic parameters along with muscle activity using this system with data of the same subjects being fully exposed to microgravity and hypergravity conditions on a parabolic flight. Both in our simulation and in-flight, we observed a significant increase in movement durations in microgravity conditions and increased velocities in hypergravity for upward movements. Additionally, we noted a reduced accuracy of pointing both in-flight and in our simulation. These promising results suggest, that locally simulated altered gravity can elicit similar changes in some movement characteristics for arm reaching movements. This could potentially be exploited as a means of developing devices such as exoskeletons to aid in training individuals prior to undertaking tasks in changed gravitational conditions.

Paving the way to better understand the effects of prolonged spaceflight on operational performance and its neural bases

“…The effects of a simulation of weightlessness (0 g) and hypergravity (1.8 g) on the same task parameters have also been investigated on ground (i.e., 1 g). Remarkably, the simulation of gravitational fields different from 1 g applied locally to the effector produced effects that were comparable to immersion in an altered gravitational field 99 . These data demonstrate that the application of simple focal forces is sufficient to reproduce the effects of gravitational changes on relevant task parameters.…”

An all-position type control strategy of the haptic interactive virtual training system based on cable-driven

“…The virtual object is the object in a virtual microgravity environment, which is used to simulate a real object in space. The motion law of the virtual object under the action of the astronaut interaction force F h is shown in equation (2). In the training, by changing the virtual object parameters (m 0 , J 0 ) and the virtual environment parameter (g 0 ), equation ( 2) can realize the motion law of the object with different mass and inertia in any microgravity environment.…”

“…1 The motion properties of objects in space are different from those of the Earth's gravity environment. 2 Due to the inability to feel gravity, the device is prone to collisions during the operation of the device by astronauts such as moving the device and dismantling the device, resulting in device damage. There are even cases of damage to astronauts due to astronauts move heavy loads, such as tearing space suits.…”

Effects of altered gravity on growth and morphology in Wolffia globosa implications for bioregenerative life support systems and space-based agriculture

“…Hypergravity, characterized by gravitational forces greater than Earth’s standard 1 g, is a significant factor in space exploration, affecting humans, and plant life 20 , 21 . Hypergravity is most prominent during the manuvers of take-off and landing phases of spacecraft.…”