Partial Weight Bearing Does Not Prevent Musculoskeletal Losses Associated with Disuse

• DOI: 10.1249/mss.0b013e318299c614
• Publication Date: 2013-05-08T11:45:03Z
• Authors: JOSHUA M. SWIFT; FLORENCE LIMA; BRANDON R. MACIAS; MATTHEW R. ALLEN; ELIZABETH S. GREENE; YASAMAN SHIRAZI-FARD; JOSHUA S. KUPKE; HARRY A. HOGAN; SUSAN A. BLOOMFIELD
• Keywords: Weight-bearing; Weightlessness

The purpose of this study was to investigate whether partial weight-bearing activity, at either one-sixth or one-third body mass, blunts the deleterious effects simulated microgravity (0G) after 21 d on muscle mass and quantitative/qualitative measures bone.Using a novel, previously validated suspension device, mice were subjected 16% (G/3, i.e., lunar gravity) 33% (G/6, Martian weight bearing for d. One gravity control (1G, Earth tail-suspended (0G, microgravity) served as controls compare both microgravity.Simulated resulted in an 8% reduction 28% lower total plantarflexor (for both, P < 0.01) compared with 1G controls, but activity attenuated losses. Relative trabecular bone volume fraction (-9% -13%) thickness (-10% -14%) significantly all groups (P 0.01). In addition, cancellous cortical formation rates (BFR) reduced (-46% -57%, BFR; -73% -85%, 0.001). Animals experiencing not exhibited deficits femoral neck mechanical strength associated 0G.These results suggest that (up mass) is sufficient protect against loss observed 0 g does mitigate reductions soleus skeletally mature female mice.