Anthropometric and computed tomographic assessment of the thigh in young and old men.

Anthropometric (AP) and computed tomographic (CT) methods of determining limb and muscle-plus-bone cross-sectional area (CSA) and volume (Vol) were compared in 13 young (M = 24.5 yrs) and 11 old (M = 71.0 yrs) men. CSA of total thigh, muscle-plus-bone, quadriceps, and hamstring muscle compartments and muscle were measured from CT scans. Corresponding muscle Vol were estimated from anthropometric equations. Prediction equations for CT measures were developed from AP measures using multiple linear regression. AP and CT techniques produced different values for thigh component CSA and Vol, especially in the old men. AP overestimated muscle-plus-bone CSA and Vol (4-6%) and underestimated skin and subcutaneous tissue CSA and Vol (17-33%). Prediction equations for quadriceps CSA and Vol (R2 = 80-96%) were more accurate than equations for hamstrings (R2 = 42-65%). Specific thigh muscle CSA and Vol can be predicted from AP measures (SEE 5-15%). These findings may have clinical significance when normalizing strength per unit of muscle size.