Crewmembers perform exercise programs during long-duration space flight to counter the detrimental effects of extended microgravity exposure. Training programs include treadmill, resistance, and cycle ergometer exercise. Exercise is performed daily by each crewmember, although volume, duration, and intensity differ across individuals. Comparison of pre- to postflight testing measures indicates that bone, muscle, and metabolic health changes vary between individuals.
This retrospective analysis was conducted using data from NASA and International partner astronauts that have flown long-duration missions onboard the International Space Station (ISS) and have had access to exercise on the Second Generation Treadmill (T2) and the Advanced Resistive Exercise Device (ARED). General exercise summary metrics were developed to quantify exercise intensities, volumes, and durations for each subject. Ground reaction force (GRF) data was used to quantify mechanical loading experienced by each astronaut. These inflight exercise metrics were investigated relative to changes in pre- to postflight medical tests related to bone and muscle health to identify which specific variables were related with improved or degraded physiological outcomes.
This study had the following specific aims:
- Quantify the exercise-related mechanical loading experienced by crewmembers on the T2 and ARED during their mission on the ISS.
- Explore relationships between exercise loading variables, bone, and muscle health changes during the mission.
- Determine if specific mechanical loading variables are more critical than others in protecting physiology.
- Develop a methodology for operational use in monitoring accumulated training loads during crew exercise programs.
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Pre- and postflight medical data including bone mineral content, bone volume, isokinetic and isometric strength was gathered for 25 subjects. Inflight exercise data including self-reported ARED exercise (sets, reps, loads and exercise type) along with automated treadmill and cycle data were collected.
The investigators conducted a variety of analyses using treadmill data to quantify the loading experienced throughout a mission. Total session and mission summary data including total exercise time, total exercise distance, and total time and distance at each speed was collected. Analyses included quantifying the number of footfalls, loading rates, impulses, the average GRF, and the total GRF were computed for each session and over the entire mission.
Summarized results for this experiment aren't available.
Bone mineral density
Exercise distance, total
Exercise resistance force
Exercise time, total
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Exercise, total repetitions performed
Ground reaction forces, average
Ground reaction forces, total
Isokinetic muscular strength
Isometric muscular strength
Number of footfalls
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.