Artificial Gravity (AG) substitutes for missing gravitational cues and loading in space and offers significant promise as an effective and efficient countermeasure against virtually all of the identified risks associated with bone loss, muscle weakening, cardiovascular deconditioning, and sensorimotor disturbances. However, the optimal AG load required for maintaining normal physiological function is unknown. Even with an AG capability, exercise is very likely to remain in the countermeasure suite because it provides additional physiological and psychological benefits. It is necessary, in understanding AG, to evaluate how AG interacts with exercise and how this interaction is influenced by partial gravity between 0 and 1 G. Parabolic flight creates the only condition that allows assessment of the effects of partial gravity in humans without the need for launching into space.
On this basis, parabolic flight research, with a range of gravitational loads, will provide a unique model to characterize the relationships among gravitational dose, exercise and the acute physiologic responses of the sensorimotor, cardiovascular, cerebrovascular, and ocular systems. This study will identify the AG dose-physiological response relationship and will involve a multidisciplinary collaboration between investigators at the Johnson Space Center with the collective expertise in cardiovascular physiology, exercise physiology, muscle physiology, sensorimotor function, and statistical analyses. The primary aims are to characterize the effects of varying gravity on VIIP-related outcomes, cardiovascular, cerebrovascular and ocular hemodynamics and pressures, calf muscle activation, neuro/vestibular outcomes associated with dynamic visual acuity, outcomes related to locomotion with body weight replacement and kinematics, and importantly, the co-relations that may exist among these physiological areas.
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Multiple parabolic flights will be used to simulate five different levels of gravity (i.e., 0, .25, .50, .75 and 1.0g), while gathering cardiac, cerebral, and ocular hemodynamics and pressure data generated by exercises on the Advanced Resistive Exercise Device (ARED), cycle ergometer, and treadmill. Kinematic data will be gathered using video (e.g. foot, shank, thigh, trunk, hip, knee, and ankle) providing displacement, velocity, acceleration, as well as contact time, stride time, and step times. Electromyography (EMG) of the calf will be completed using a telemetry system with bipolar surface electrodes placed on the soleus and lateral gastrocnemius. Visual acuity will be assessed during static and dynamic conditions at two target distances during the various g-levels. The difference in these two measures is Dynamic Visual Acuity (DVA), the acuity decrement associated with not being able to maintain gaze while moving. All subjects will participate in each condition for each of the different gravity levels.
This study is in progress. Results will be updated when available.
Crew health and performance is critical to successful human exploration beyond low Earth orbit.
The Human Research Program (HRP) investigates and mitigates the highest risks to human health
and performance, providing essential countermeasures and technologies for human space exploration.
Risks include physiological and performance effects from hazards such as radiation, altered gravity,
and hostile environments, as well as unique challenges in medical support, human factors,
and behavioral health support. The HRP utilizes an Integrated Research Plan (IRP) to identify
the approach and research activities planned to address these risks, which are assigned to specific
Elements within the program. The Human Research Roadmap is the web-based tool for communicating the IRP content.
The Human Research Roadmap is located at: https://humanresearchroadmap.nasa.gov/
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for information of how this experiment is contributing to the HRP's path for risk reduction.