Femur-bending properties as influenced by gravity: III. Sex-related weakness after 4-G mouse growth.

Optimum gravitational intensity for growth stimulation depends upon the type of growth measurement. Although the 4-G field resulted in relatively weaker male bones, relative bone size increased. The more moderate 3-G field is known to stimulate relative bone-strength as well. Femurs from 36 male white mice demonstrated no growth of load-supporting ability Fu after 1 to 8 weeks of chronic centrifugation at 4-G from the fifth week of age. Although measurable with 35 female mice, this growth intended to fall below the control rate. When compared to 82 younger control femurs of the same cross-sectional geometry, experimental female femurs could sustain comparable moments Mu while experimental male femurs could not.