| POSTDOCTORAL FELLOWSHIP
The project addresses the shortcoming in musculoskeletal maintenance by examining the current International Space Station (ISS) exercise protocols through computer simulation. Specifically, this project will use the LifeMOD/MD Adams biomechanics simulation software to characterize how Advanced Resistive Exercise Device (ARED)-like exercises impact hip joint contact forces. The hip is a region of the skeleton that experiences the greatest loss in bone mineral density (1.2-1.5% per month) and strength during long-duration missions in microgravity.
This study aims to examine why current exercise countermeasures are not sufficiently maintaining bone health and to characterize the hip-loading forces during ARED-like exercise. Characterizing the hip forces experienced during ISS exercise protocols assigned to crews will provide a baseline from which to adjust exercises to better protect the hip. Ultimately, the study will result in a recommendation of more efficacious exercise protocols with the goal of increasing loading forces to better protect the hip joint based on computer simulations. In addition to ISS exercise, an examination of similar exercises in reduced-gravity environments will also be performed.
1. Characterize the hip joint contact forces that result during ARED-like exercise through computer simulation.
2. Examine how the use of gravity replacement loads affect hip joint forces in microgravity and partial gravity environments.
3. Perform a sensitivity analysis to examine and optimize the contributions of muscle forces to joint forces.
The proposed project fulfills the following anticipated deliverables of the NSBRI Musculoskeletal Alterations Team: 1) ground-based simulation of on-orbit exercise devices; 2) specific exercise prescriptions tailored to individual astronauts; and, 3) designing improved exercise devices.
Additionally, gender-specific models can be developed to address the questions of gender-specific effects of bone loss and exercise countermeasures outlined throughout the NASA Human Research Program's Integrated Research Plan.