Initial State: Unloading during space flight is certainly a contributing factor to space flight-induced muscle atrophy. Space flight analogs for unloading such as bed rest and unilateral lower limb suspension support this. Nevertheless, it remains feasible that unloading  may not be the sole contributing factor to skeletal muscle atrophy during space flight. Additional space-flight related stimuli could be co-contributors. If this were to be the case, then simply addressing the loading issue alone may be insufficient to protect muscle fitness. Potential factors include inflammation, redox balance, energy balance, hydration, etc.

Interim Stages:
Identification of candidate contributors
Determine the role of each contributor

Approach: Human and animal research will be conducted to address possible loading-independent contributors to space flight-induced atrophy.