NASA EPSCoR: R3 SOMD RFA-070: Use of Velocity Monitoring to Prescribe Appropriate Flywheel-based Inertial Training (FIT) workloads for Exercise in Space Flight

Proposal Summary (abstract) Space flight exposure induces rapid loss of skeletal muscle strength which is a function of loss of muscle size as well as motor unit recruitment which is primarily attributed to muscle unloading. Flywheel-based Inertial Training (FIT) is a non-gravity dependent form of resistance exercise that shows promise in mitigating space flight-induced muscle atrophy and is routinely used by European crew members aboard the ISS. Conventional FIT protocols have inadequately addressed FIT workload on an individualized manner with respect to subject strength. Terrestrial precision health solutions indicate that velocity-based training (VBT) elicits greater gains in muscle size, strength, and physical function than conventional load-based paradigms. Furthermore, use of velocity monitoring has been determined to be an effective means of prescribing appropriate FIT workloads in athletes. This proposal aims to determine how use of velocity-based training domains during FIT exercise affects motor unit recruitment and muscle remodeling during a 30d unilateral lower limb suspension (ULLS) protocol. Furthermore, this proposal explores two candidate biomarkers as potential precision health assessments for future studies. We hypothesize that ULLS will reduce voluntary muscle strength, size, and motor unit recruitment, but that these effects will be prevented in subjects completing FIT. Deliverables from this project include actionable precision resistance training interventions for crew members using established hardware and training protocols from terrestrial settings. Furthermore, our data will provide an advanced understanding of motor unit recruitment and muscle remodeling that occurs with prolonged unloading.