The specific objectives of this experiment are:
1. To establish the efficacy of a 10-minute daily in-flight dose of high frequency (30Hz), low magnitude (0.3-G, or 3m s-2) mechanical acceleration to inhibit the loss of bone density in the lower appendicular and axial skeleton.
2. To establish the efficacy of this same stimulus to inhibit the loss of muscle strength and postural stability in the lower appendicular skeleton.
Following flight durations of at least three months, the bone quantity and quality will be evaluated by comparing postflight DXA, QCT and ultrasound measurements to baseline (preflight measurements). The principal areas of interest will be R&L femora, tibia, calcaneus, the spine (L1-4), and non-dominant radius. Assays will evaluate bone density, trabecular and cortical bone density, cortical thickness, apparent bone quality, and bone mineral density. Muscle strength and postural stability will also be evaluated, again comparing pre and post-launch data.
Differences from the baseline will be examined in terms of the ability of extremely low-level mechanical stimulation to inhibit the loss of bone quality and quantity. The preservation of muscle strength and postural stability, as based on these mechanical signals will provide a key to the regulatory stimulus in the maintenance of the musculoskeletal system.
Efficacy will be determined as based on the ability of the signal to inhibit bone loss, prevent loss of muscle power and loss of postural stability as compared to controls. Given the ground-based evidence, we anticipate that treated crewmembers will retain bone density and muscle strength regardless of the deleterious consequences of the absence of gravity. Further, it is anticipated that bone loss in the axial skeleton (spine) will be reduced through exposure to the low-level mechanical signal.
Three clinical studies have been completed (post-menopausal women, children with cerebral palsy, young women w/ osteoporosis), each which supports the hypothesis that low-level mechanical signals can benefit the mass and morphology of the musculoskeletal system.
This investigation has been demanifested; therefore, there are no results available from this experiment.